• TABLE OF CONTENTS
HIDE
 Management of the western flower...
 Biology and ecology of the western...
 Management of flower thrips in...
 Education and training to increase...
 Assessment of implementation and...
 Shifts in western flower thrips,...
 Evaluation of natural enemies and...
 Description of the mature larva...
 Biology of Stethoconus praefectus...
 Fecundity of Larra bicolor (Hymenoptera:...
 Two new species of Aulacorthum...
 Use of landscape fabric to manage...
 Cytological attributes of sperm...
 Description of a new cicada in...
 Impact of residual insecticide...
 Effects of beetle density and time...
 Identification of fire ants (Hymenoptera:...
 Assimilation efficiency of free...
 Acoustic characteristics of dynastid...
 New species of Merocoris (Merocoris)...
 A new species of Chaenusa (Hymenoptera:...
 Southern highbush blueberries are...
 Suppression of Myllocerus undatus...
 Native North American Azolla weevil,...
 Temporal distribution of egg hatch...
 Effect of irradiation on the incidence...
 Nerthra fuscipes, a toad bug (Hemiptera:...
 Litter-dwelling arthropod abundance...
 Monitoring the small hive beetle...
 Molecular identification of the...
 Anastrepha edentata and other fruit...
 New county and state records for...
 An introduced insect biological...
 New record of thrips species associated...
 Book reviews
 Back Matter














Group Title: Florida Entomologist
Title: The Florida entomologist
ALL VOLUMES CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00098813/00359
 Material Information
Title: The Florida entomologist
Uniform Title: Florida entomologist (Online)
Abbreviated Title: Fla. entomol. (Online)
Physical Description: Serial
Language: English
Creator: Florida Entomological Society
Florida Center for Library Automation
Publisher: Florida Entomological Society
Place of Publication: Gainesville Fla
Gainesville, Fla
Publication Date: March 2009
Frequency: quarterly
regular
 Subjects
Subject: Entomology -- Periodicals   ( lcsh )
Insects -- Periodicals -- Florida   ( lcsh )
Genre: review   ( marcgt )
periodical   ( marcgt )
 Notes
Additional Physical Form: Also issued in print.
System Details: Mode of access: World Wide Web.
Language: In English; summaries in Spanish.
Dates or Sequential Designation: Vol. 4, no. 1 (July 1920)-
Issuing Body: Official organ of the Florida Entomological Society; online publication a joint project of the Florida Entomological Society and the Florida Center for Library Automation.
General Note: Title from caption (JSTOR, viewed Sept. 13, 2006).
General Note: Place of publication varies.
General Note: Latest issue consulted: Vol. 87, no. 4 (Dec. 2004) (JSTOR, viewed Sept. 13, 2006).
 Record Information
Bibliographic ID: UF00098813
Volume ID: VID00359
Source Institution: University of Florida
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Resource Identifier: isbn - 0015-4040
issn - 1938-5102
oclc - 33223434
lccn - sn 95026670
 Related Items
Preceded by: Florida buggist (Online)

Table of Contents
    Management of the western flower thrips (Thysanoptera: Thripidae) in fruiting vegetables
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
    Biology and ecology of the western flower thrips (Thysanoptera: Thripidae): the making of a pest
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
    Management of flower thrips in blueberries in Florida
        Page 14
        Page 15
        Page 16
        Page 17
    Education and training to increase adoption of IPM for western flower thrips, Frankliniella occidentalis (Thysanoptera: Thripidae)
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
        Page 23
    Assessment of implementation and sustainability of integrated pest management programs
        Page 24
        Page 25
        Page 26
        Page 27
        Page 28
    Shifts in western flower thrips, Frankliniella occidentalis (Thysanoptera: Thripidae), population abundance and crop damage
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
        Page 34
    Evaluation of natural enemies and insecticides for control of Pseudacysta perseae (Hemiptera: Tingidae) on avocados in southern California
        Page 35
        Page 36
        Page 37
        Page 38
        Page 39
        Page 40
        Page 41
        Page 42
    Description of the mature larva of the sand wasp Bembix bidentata and its parasitoids.(Hymenoptera: Crabronidae, Chrysididae, Mutillidae)
        Page 43
        Page 44
        Page 45
        Page 46
        Page 47
        Page 48
        Page 49
        Page 50
        Page 51
        Page 52
        Page 53
    Biology of Stethoconus praefectus (Distant) (Heteroptera: Miridae), a newly established predator of the avocado lace bug, Pseudacysta perseae (Heteroptera: Tingidae), in Florida
        Page 54
        Page 55
        Page 56
        Page 57
    Fecundity of Larra bicolor (Hymenoptera: Crabronidae) and its implications in parasitoid: host interaction with mole crickets (Orthoptera: Gryllotalpidae: Scapteriscus)
        Page 58
        Page 59
        Page 60
        Page 61
        Page 62
        Page 63
    Two new species of Aulacorthum (Hemiptera: Aphididae) from Korea
        Page 64
        Page 65
        Page 66
        Page 67
        Page 68
        Page 69
        Page 70
        Page 71
        Page 72
        Page 73
    Use of landscape fabric to manage diaprepes root weevil in citrus groves
        Page 74
        Page 75
        Page 76
        Page 77
        Page 78
        Page 79
    Cytological attributes of sperm bundles unique to F1 progeny of irradiated male Lepidoptera: relevance to sterile insect technique programs
        Page 80
        Page 81
        Page 82
        Page 83
        Page 84
        Page 85
        Page 86
        Page 86a
        Page 86b
    Description of a new cicada in the genus Dilobopyga (Hemiptera: Cicadidae)
        Page 87
        Page 88
        Page 89
        Page 90
    Impact of residual insecticide applied to upper story vegetation on resting adult mosquitoes (Diptera: Culicidae)
        Page 91
        Page 92
        Page 93
        Page 94
        Page 95
        Page 96
        Page 97
        Page 98
    Effects of beetle density and time of day on the dispersal of Gratiana boliviana (Coleoptera: Chrysomelidae)
        Page 99
        Page 100
        Page 101
        Page 102
        Page 103
        Page 104
        Page 105
        Page 106
    Identification of fire ants (Hymenoptera: Formicidae) from Northeastern Mexico with morphology and molecular markers
        Page 107
        Page 108
        Page 109
        Page 110
        Page 111
        Page 112
        Page 113
        Page 114
        Page 115
    Assimilation efficiency of free and protein amino acids by Homalodisca vitripennis (hemiptera: cicadellidae: cicadellinae) feeding on Citrus sinensis and Vitis vinifera
        Page 116
        Page 117
        Page 118
        Page 119
        Page 120
        Page 121
        Page 122
    Acoustic characteristics of dynastid beetle stridulations
        Page 123
        Page 124
        Page 125
        Page 126
        Page 127
        Page 128
        Page 129
        Page 130
        Page 131
        Page 132
        Page 133
    New species of Merocoris (Merocoris) perty from Brazil, with keys to known subgenera and species of the tribe Merocorini (Hemiptera: Heteroptera: Coreidae: Meropachyinae)
        Page 134
        Page 135
        Page 136
        Page 137
        Page 138
    A new species of Chaenusa (Hymenoptera: Braconidae) reared from Hydrellia pakistanae and Hydrellia sarahae laticapsula (Diptera: Ephydridae) infesting Hydrilla verticillata (Alismatales: Hydrocharitaceae) in India and Pakistan
        Page 139
        Page 140
        Page 141
        Page 142
        Page 143
        Page 144
        Page 145
        Page 146
    Southern highbush blueberries are a new host for Scirtothrips citri (thysanoptera: thripidae) in California
        Page 147
        Page 148
        Page 149
    Suppression of Myllocerus undatus (Coleoptera: Curculionidae) in Valencia orange with chlorpyrifos sprays directed at ground and foliage
        Page 150
        Page 151
        Page 152
    Native North American Azolla weevil, Stenopelmus rufinasus (Coleoptera: Curculionidae), uses the invasive old world Azolla pinnata as a host plant
        Page 153
        Page 154
        Page 155
    Temporal distribution of egg hatch for two Homalodisca SPP. (Hemiptera: Cicadellidae) under constant temperatures
        Page 156
        Page 157
        Page 158
    Effect of irradiation on the incidence of mating in Cactoblastis cactorum
        Page 159
        Page 160
    Nerthra fuscipes, a toad bug (Hemiptera: Gelastocoridae) new to the USA, established in Florida
        Page 161
        Page 162
    Litter-dwelling arthropod abundance peaks near coarse woody debris in loblolly pine forests of the southeastern United States
        Page 163
        Page 164
    Monitoring the small hive beetle Aethina tumida (Coleoptera: Nitidulidae) with baited flight traps: effect of distance from bee hives and shade on the numbers of beetles captured
        Page 165
        Page 166
    Molecular identification of the economically important invasive citrus root weevil Diaprepes abbreviatus (Coleoptera: Curculionidae)
        Page 167
        Page 168
        Page 169
        Page 170
        Page 171
        Page 172
    Anastrepha edentata and other fruit flies (Diptera: Tephritidae) detected on Key Largo, Florida
        Page 173
        Page 174
        Page 175
        Page 176
    New county and state records for Tennessee of an exotic pest, Halyomorpha halys (Hemiptera: Pentatomidae), with potential economic and ecological implications
        Page 177
        Page 178
    An introduced insect biological control agent preys on an introduced weed biological control agent
        Page 179
        Page 180
    New record of thrips species associated with soybeans in Puerto Rico
        Page 181
        Page 182
        Page 183
        Page 184
        Page 185
        Page 185a
        Page 185b
        Page 185c
    Book reviews
        Page 186
        Page 187
        Page 188
        Page 189
        Page 190
    Back Matter
        Page 191
        Page 192
Full Text



Funderburk: Thrips Management in Fruiting Vegetables


MANAGEMENT OF THE WESTERN FLOWER THRIPS
(THYSANOPTERA: THRIPIDAE) IN FRUITING VEGETABLES


JOE FUNDERBURK
North Florida Research and Education Center, University of Florida, 155 Research Road, Quincy, FL 32351

ABSTRACT

Feeding by the western flower thrips, Frankliniella occidentalis (Pergande), causes damage
to the fruits of vegetables, and the species is the key vector of Tomato spotted wilt virus.
Frankliniella tritici (Fitch) and Frankliniella bispinosa (Morgan) are not pests of fruiting
vegetables. Both species compete with F occidentalis. Effective management of F occiden-
talis in pepper integrates conservation of natural populations of the predator, Orius insidio-
sus (Say), with the use of reduced-risk insecticides such as spinetoram for the control of
western flower thrips and other pests. Naturally occurring 0. insidiosus are very effective
predators and their effectiveness is predictable based on the number of the predator relative
to the number of thrips prey. Populations of F occidentalis resurge when natural enemies
and competing thrips are killed. Some insecticides especially pyrethroids have beneficial ef-
fects on the development and reproduction ofF. occidentalis. The predator 0. insidiosus does
not prefer tomato, and numbers remain too low in fields to suppress thrips. Tomato growers
primarily rely on the use of ultra-violet reflective mulch combined, if needed, with the use
of effective insecticides. Additional management efforts are needed in the future to manage
F occidentalis and other difficult pests in space and time. Management of the pepper weevil
(Anthonomus eugenii Cano) is proving a challenge to pepper growers in central and southern
Florida trying at the same time to manage F occidentalis. Growers need to emphasize san-
itation and other cultural tactics over the use of broad-spectrum insecticides that kill O. in-
sidiosus and induce F occidentalis in other ways. The identification of thrips in scouting
programs also is critical as the use of broad-spectrum insecticides against populations of the
non-pest flower thrips is inducing F occidentalis to pest status.

Key Words: Frankliniella occidentalis, pepper, eggplant, tomato, IPM

RESUME

La alimentaci6n del trips occidental de las flores, Frankliniella occidentalis (Pergande),
causa dano a los frutos de verduras y a su vez la especie es el vector clave del virus de la mar-
chitez manchada del tomate. Frankliniella tritici (Fitch) y Frankliniella bispinosa (Morgan)
no son plagas de verduras que produce frutos. Ambas species compiten con F occidentalis.
El manejo efectivo de F. occidentalis en chile se integra con la conservaci6n de poblaciones
naturales del depredador, Orius insidiosus (Say) con el uso de insecticides de riesgo reduci-
dos como el "spinetoram" para el control del trips occidental de las flores y otros plagas.
Cuando 0. insidiosus ocurre son depredadores muy efectivos y su efectividad es previsible
basado sobre el numero de depredadores en relaci6n al numero de trips (presa). Poblaciones
de F occidentalis resurgen cuando se matan los enemigos naturales y trips competidores. Al-
gunos insecticides especialmente los piretroides tienen unos efectos ben6ficos sobre el desa-
rrollo y reproducci6n de F. occidentalis. El depredador 0. insidiosus no prefiere el tomate y
el numero de individuos se mantiene demasiado bajo en campos para suprimir los trips. Los
productores de tomate dependent primariamente sobre el uso de mantillo reflectante de ultra
violeta combinado, si es necesario, con el uso de insecticides efectivos. Se necesita esfuerzos
adicionales en un future para manejar F. occidentalis y otras plagas dificiles en un espacio
y un tiempo. El manejo del gorgojo (picudo) de chile (Anthonomus eugenii Cano) esta ha-
ciendo un desaffo para los productores de chile en el centro y sur de la Florida, quienes tra-
tan a la vez de manejar el trips F. occidentalis. Los productores necesitan enfatizar mas la
sanidad y otras tacticas culturales que en el uso de insecticides de amplio espectro que eli-
mina 0. insidiosus e induce F. occidentalis en otras maneras. La identificaci6n de trips en
programs de muestreo tambi6n es crucial puesto que los insecticides de amplio espectro
contra poblaciones de diferentes trips de flores que no son plaga esta induciendo F. occiden-
talis a nivel de plaga.


There are over 5000 described species of thrips deformity, and reduced marketability (Mound
(Thysanoptera). About 87 species of thrips are 1997). Over 20 of these species of thrips are now
pests of commercial crops because they feed on cosmopolitan (Mound 1997), including recent in-
leaves, fruits, and flowers causing discoloration, vasive species in Florida, the chilli thrips, Scirto-







Florida Entomologist 92(1)


thrips dorsalis (Hood), and a legume pest, Mega-
lurothrips mucunae (Priesner) (Diffie et al. 2008).
Global trade in greenhouse plants rapidly spread
the western flower thrips, Frankliniella occiden-
talis (Pergande), around the world in the 1980s.
The species is native to the southwestern US, and
it is the key vector of Tomato spotted wilt virus
(Kirk & Terry 2003). The insect and the virus
emerged as the key pest problems of tomato, pep-
per, peanut, tobacco, and other crops in northern
Florida in 1986. In 2006, the western flower
thrips (but not the virus) emerged as a key pest
problem in fruiting vegetables in central and
southern Florida.
The adults ofF occidentalis inhabit the flowers
of tomato, pepper, and eggplant, where they feed
on pollen and flower tissues. The female lays eggs
individually in the small developing fruit of the
flower. A small dimple sometimes surrounded by
a halo remains in the developing fruit after egg
hatch (Salguero Navas et al. 1991b). The dimple,
but not necessarily the halo, remains on mature
fruits. Direct feeding by larvae also causes aes-
thetic damage referred to as 'flecking' (Ghidiu et
al. 2006). This damage occurs on the parts of the
fruit touching a leaf or stem due to the cryptic
habits of the larvae. Thrips damage can result in
cull-out and lowering of grade of the harvested
fruit, with tolerance based on price and demand
in the marketplace. Plants infected by Tomato
spotted wilt virus display chlorosis, necrosis, ring-
spotting, and other symptoms, and fruits of in-
fected plants are not marketable.
Other species of thrips occur in large numbers
in the flowers of fruiting vegetables in Florida.
The most common species in northern Florida is
Frankliniella tritici (Fitch) (Reitz 2002; Salguero
Navas et al. 1991a). The species does not damage
fruits even in very large numbers (Salguero Na-
vas et al. 1991b), and it is not a capable vector of
Tomato spotted wilt virus (de Assis Filho 2005).
The most common species in central and southern
Florida is Frankliniella bispinosa (Morgan)
(Hansen et al. 2003). The species is a capable vec-
tor of Tomato spotted wilt virus (Avila et al. 2006).
The tobacco thrips, Frankliniella fusca (Hinds),
occurs in low numbers in fruiting vegetables in
northern Florida, and Frankliniella schultzei
(Trybom) occurs in low numbers in central and
southern Florida (Hansen et al. 2003). These spe-
cies are capable vectors of Tomato spotted wilt vi-
rus.
The unusual virus-vector relationship is a par-
ticular challenge in efforts to manage Tomato
spotted wilt virus. The virus is acquired only by
the larvae, and the adults transmit it to host
plants. Usually primary spread of the disease is
due to infections caused by incoming viruliferous
adults to a crop from outside sources that include
uncultivated and cultivated plant hosts. Adults
persistently transmit, and their control with in-


secticides does not prevent transmission due to
the short time of feeding for infection to occur
(Momol et al. 2004). Secondary spread is caused
by viruliferous adults that acquired the virus as
larvae feeding on an already infected plant. For
secondary spread, thrips need to colonize and re-
produce on infected plants within a crop. Control
of the larvae before their development to adults is
effective in preventing secondary spread. Most vi-
ral infections in tomatoes in northern Florida are
the result of primary spread, although some sec-
ondary viral infections occur late in the season
(Momol et al. 2004). The lack of epidemics of to-
mato spotted wilt disease in vegetables in central
and southern Florida suggests that F bispinosa is
not an efficient vector capable of acquiring the To-
mato spotted wilt virus from uncultivated plant
species.
A lack of knowledge of the reproductive host
plants serving as sources of thrips invading crop
fields in northern Florida has hampered manage-
ment efforts, but see Paini et al. (2007) and North-
field et al. (2008). Paini et al. (2007) identified
only 2 uncultivated plant species serving as re-
productive hosts for F occidentalis in the agricul-
tural landscape in northern Florida, while 18 un-
cultivated plant species served as reproductive
hosts for F tritici. Northfield et al. (2008) studied
the population dynamics of Frankliniella species
thrips on 7 common, uncultivated plant species in
northern Florida. Only 1.1% of the thrips col-
lected were F occidentalis, while 75.9% were F
tritici. The invasive F occidentalis apparently is
out-competed by the native F tritici on shared
crop and uncultivated plant hosts (Paini et al.
2008). The adults of F occidentalis are not abun-
dant on uncultivated plant species in central and
southern Florida (J. E. F., unpublished), which
suggests that the abundant F bispinosa is an ef-
fective competitor species with F occidentalis.
The invading populations of F occidentalis
were largely resistant to most organophosphate,
carbamate, pyrethroid, and organochlorine insec-
ticides (Immaraju et al. 1992). Application of
these broad-spectrum insecticides may suppress
F occidentalis populations initially, but their
numbers can increase rapidly a few days after ap-
plication (Funderburk et al. 2000; Ramachandran
et al. 2001; Reitz et al. 2003). Further, insecticidal
control of the viruliferous adults proved ineffec-
tive in preventing primary spread of Tomato spot-
ted wilt virus (Momol et al. 2004). Yet, growers in
northern Florida responded (as have growers in
most other parts of the world) by spraying insec-
ticides on a calendar schedule. This resulted in an
ecological and economic crisis with growers in
northern Florida suffering uncontrollable dam-
age due to high thrips populations and epidemics
of tomato spotted wilt disease. Eventually, inte-
grated pest management programs were devel-
oped for fruiting vegetables, and they proved to be


March 2009







Funderburk: Thrips Management in Fruiting Vegetables


effective, economic, and sustainable. A review of
these programs that are widely implemented in
northern Florida is given, including a discussion
of the mechanisms by which the tactics reduce
thrips populations. Recently populations of E oc-
cidentalis in central and southern Florida have
increased in crops grown during the winter and
spring. Large, damaging populations have oc-
curred in fruiting vegetables. The reasons for the
emergence of Foccidentalis as a key pest of fruit-
ing vegetables in central and southern Florida are
discussed. The need for and the potential benefits
of additional tactics in the integrated pest man-
agement of Foccidentalis are evaluated. A case is
made that there is a need to vertically integrate
management of F occidentalis and other insect
pests of fruiting vegetables.

INTEGRATED PEST MANAGEMENT FOR PEPPER

The naturally occurring minute pirate bugs
Orius insidiosus are very effective predators of
thrips in pepper. Species of Orius in the family
Anthocoridae are commonly referred to as minute
pirate bugs, while the common name for 0. insid-
iosus is the insidious flower bug. Their effective-
ness is predictable based on the number of the
predator relative to the number of thrips prey
(Funderburk et al. 2000; Ramachandran et al.
2001). Suppression occurs when there is 1 preda-
tor for approximately 180 thrips and control oc-
curs when there is 1 0. insidiosus per approxi-
mately 50 thrips.
A conservation biological control program was
implemented in northern Florida beginning in
1997. This integrated pest management program
employs reduced-risk insecticides and natural
populations of 0. insidiosus (Funderburk et al.
2000; Ramachandran et al. 2001; Reitz et al.
2003). There is a lag period once peppers begin
flowering in the spring season in which thrips col-
onize and buildup to large numbers for about a
week before there are enough 0. insidiosus to sup-
press and control thrips populations (Funderburk
et al. 2000; Ramachandran et al. 2001). The num-
ber ofthrips in flowers can exceed 10 per flower in
untreated spring pepper during this lag period,
but there is no damage to the pepper fruits.
Minute pirate bugs are effective predators of
the adults and larvae of each of the Frankliniella
species (Funderburk et al. 2000; Ramachandran
et al. 2001; Reitz et al. 2003), although 0. insidio-
sus has distinct prey preferences. The larvae are
the first to be suppressed, followed by the adults
of F occidentalis (Baez et al. 2003). The adults of
F tritici and F bispinosa are the most mobile and
best able to escape predation (Reitz et al. 2004).
Populations of 0. insidiosus occur in large
numbers in the landscape in northern Florida
from May to Nov, and populations invade spring
and fall pepper in numbers sufficient to control


thrips (Ramachandran et al. 2001). Populations
persist in spring pepper flowers after thrips pop-
ulations have been suppressed in numbers suffi-
cient to prevent re-building of thrips populations
(Funderburk et al. 2000; Ramachandran et al.
2001; Reitz et al. 2003). The numbers of 0. insid-
iosus in pepper flowers are sufficient throughout
the fall production season to prevent population
buildup of thrips (Ramachandran et al. 2001).
The conservation biological control program
has been adapted to local conditions throughout
the world. This integrated pest management pro-
gram employs reduced-risk insecticides, natural
infestations of minute pirate bugs, and cultural
control tactics including ultraviolet-reflective
mulch (Reitz et al. 2003). The ultraviolet-reflec-
tive mulch repels the migrating adults of F occi-
dentalis, and this reduces the primary spread of
Tomato spotted wilt virus (Reitz et al. 2003).
There is a substantial reduction in the population
buildup of thrips. There also is a delay in the
buildup of populations of minute pirate bugs, but
overall the benefits of the ultraviolet-reflective
mulch outweigh the initial reduction in biological
control (Reitz et al. 2003).
Spinosyn insecticides represent a unique mode
of action (Group V insecticides). The spinosyns
spinosad and spinetoram (Dow AgroSciences, In-
dianapolis, IN) are the most effective insecticides
to suppress F occidentalis, and they are reduced-
risk insecticides that do not suppress populations
of 0. insidiosus at labeled rates (Funderburk et
al. 2000; Reitz et al. 2003; Srivastava et al. 2008).
Other reduced-risk insecticides labeled for fruit-
ing vegetables have little or no efficacy against F
occidentalis, although 2 with moderate efficacy
are soon to be labeled (Table 1). Other reduced-
risk insecticides that are not efficacious against F
occidentalis but conserve populations of 0. insid-
iosus, are useful in the control of lepidopterous
and other pests in pepper (Table 1).
A number of insecticides, either alone or in
combination, have been documented to result in a
significant buildup of populations of F occidenta-
lis in pepper compared to untreated pepper (Table
2). This phenomenon is especially consistent
when pyrethroid insecticides are applied, but in-
secticides in other insecticidal classes also induce
populations. The mechanism has been directly re-
lated to suppression of populations of the key
predator, 0. insidiosus (Funderburk et al. 2000;
Ramachandran et al. 2001; Reitz et al. 2003;
Srivastava et al. 2008); however, other mecha-
nisms also are responsible. Populations ofF trit-
ici have been shown to out-compete populations of
F occidentalis in pepper (Paini et al. 2008). Hor-
moligosis also appears to be a mechanism, but
this has not been documented to the author's
knowledge in a refereed journal article.
The management of other insect pests has
been vertically integrated with the conservation







Florida Entomologist 92(1)


TABLE 1. INSECTICIDES LABELED OR UNDER REVIEW FOR FRUITING VEGETABLES THAT ARE COMPATIBLE WITH THE CON-
SERVATION BIOLOGICAL PROGRAM USING O. INSIDIOSUS.

Insecticide (common name) Activity Source

Spinosad thrips and other taxa Funderburk et al. (2000)
Spinetoram thrips and other taxa Srivastava et al. (2008)
Pyridadyl' thrips and other taxa J. E. F., unpublished
RequiemTM (essential oils)' thrips, aphids, whiteflies J. E. F., unpublished
Methoxyfenoxide Lepidoptera A. Weiss, unpublished
Indoxacarb Lepidoptera Reitz et al. (2003)
Bacillus thuringiensis Lepidoptera, Coleoptera J. E. F., unpublished
EcoTrolTM (essential oils) thrips and other taxa J. E. F., unpublished

Registration under review by the U.S. Environmental Protection Agency.


biological control of F occidentalis in pepper in
northern Florida. Various species of stink bugs
are occasional pests in pepper, but the application
of broad-spectrum insecticides for their control
late in the production season has not resulted in
inducing populations of F occidentalis to damag-
ing levels (J. E. F. personal observation). The pep-
per weevil, Anthonomus eugenii Cano, is an occa-
sional pest in sweet pepper especially in the fall
production season that is effectively managed pri-
marily through cultural tactics. The conservation
biological control program for thrips has resulted
in increased biological control of other pests such
as aphids by natural infestations of coccinellid
species (J. E. F., personal observation).

INTEGRATED PEST MANAGEMENT FOR TOMATO

Producers in northern Florida initially re-
sponded to the threat of F occidentalis and To-
mato spotted wilt virus by the calendar applica-
tion of broad-spectrum highly toxic insecticides.
Tomato growers applied insecticides an average
12.3 to 16.4 times per season (Bauske et al. 1998).
Yet research revealed that losses were the result
of primary infections that were not prevented by
such intensive insecticide use (Puche et al. 1995).
Salguero Navas et al. (1994) established a thresh-
old of one half of tomato flowers infested by F oc-
cidentalis to prevent dimpling and flecking. How-
ever, efforts to develop therapeutic strategies


were hampered by a lack of a practical method to
identify the species of thrips in scouting pro-
grams. Usually, most of the thrips in the flowers
were non-pest species that are highly susceptible
to most insecticides.
In laboratory assays against un-exposed feral
populations of Frankliniella species baseline tox-
icities were established for spinosad (Eger et al.
1998). These assays showed that the insecticide
was equally toxic to F occidentalis, F tritici, and F
bispinosa. The adults of F tritici and F bispinosa
are very active and they re-invade insecticide
treated fields very quickly, so that there is an ap-
parent rather than real lack of control when
short-residual insecticides such as spinosad are
applied (Ramachandran et al. 2001). Conversely,
the adults of F occidentalis are much less active,
preferring to stay on a suitable resource.
The benefits of other management tactics were
investigated, and an effective sustainable pro-
gram was developed that was adopted by tomato
growers in northern Florida (Momol et al. 2004).
Ultraviolet-reflective mulch is very effective in re-
ducing colonization of Frankiniella species thrips
onto the tomato plants and in reducing the inci-
dence of tomato spotted wilt. Development of the
larval instars is about 5 d, and weekly applica-
tions of insecticides are sufficient to prevent suc-
cessful larva development and subsequent sec-
ondary spread of Tomato spotted wilt virus. Meth-
amidophos (Monitor, Valent USA Corp. Walnut


TABLE 2. INSECTICIDES AND INSECTICIDE COMBINATIONS KNOWN TO INDUCE POPULATIONS OF FRANKLINIELLA OCCI-
DENTALIS IN PEPPER.

Insecticide (common name) Source

Fenpropathrin Funderburk et al. (2000)
lambda-cyhalothrin J. E. F., unpublished
Dinotefuran J. E. F., unpublished
zeta-cypermethrin & bifenthrin J. E. F., unpublished
Esfenvalerate Funderburk et al. (2000); Hansen et al. (2003); Ramachandran et al. (2001);
Reitz et al. (2003); Srivastava et al. (2008)


March 2009







Funderburk: Thrips Management in Fruiting Vegetables


Creek, CA) and spinosad are in different chemical
classes with different modes of action. Alternat-
ing applications for thrips control during the sea-
son is recommended as an integrated resistance
management strategy. Few other insecticides
with activity against F occidentalis currently are
labeled in tomato. Acibenzolar-S-methyl (Acti-
gard, Syngenta, Inc., Greensboro, NC) is an in-
ducer of systemic resistance and it has some ben-
efit in reducing the incidence of tomato spotted
wilt (Momol et al. 2004). It is especially recom-
mended for the control of bacterial disease as a re-
placement for copper that reduces the ultraviolet
reflection from the mulches.
Over-fertilization above recommended rates of
nitrogen for optimal production results in an in-
crease in the numbers of vector and nonvector
Frankliniella thrips and an increased incidence in
tomato spotted wilt (Stavisky et al. 2002). The in-
creased level of aromatic amino acids in over-fer-
tilized tomato plants results in an increased pref-
erence and performance of the females of F occi-
dentalis (Brodbeck et al. 2001).
Primary spread of Tomato spotted wilt virus
accounts for most of the incidence of the disease in
northern Florida, although secondary spread
must also be managed mid and late season (Mo-
mol et al. 2004). Cultivars resistant to Tomato
spotted wilt virus with acceptable yield and fruit
quality are available, and growers are rapidly
adopting resistant cultivars in northern Florida.
Strains of Tomato spotted wilt virus that have
overcome resistance from the single-gene domi-
nate trait have appeared in other geographical ar-
eas (Rosello et al. 1998). An integrated approach
therefore is necessary to reduce feeding by thrips
and to manage the development of virus strains
that can overcome host plant resistance.

DEVELOPING PROGRAMS FOR CENTRAL
AND SOUTHERN FLORIDA

The problem with F occidentalis in southern
Florida over the past 2 years appears to be in
large measure induced by the use of broad-spec-
trum insecticides, especially pyrethroids (per-
sonal observation). This is the result of a shift in
attitude by some growers to control rather than
manage pests. So, the development and imple-
mentation of integrated pest management pro-
grams for F occidentalis in fruiting vegetables is
a critical issue. Clearly, a therapeutic approach is
hampered by the lack of scouting in which thrips
are identified to species. The identification of spe-
cies is necessary in order to eliminate applica-
tions of insecticides against F bispinosa. The eco-
nomic thresholds established for thrips in pep-
pers and tomatoes are largely nominal thresholds
(i.e., developed from experience). At least 10 adult
thrips of any species can be tolerated in pepper
without damage from feeding. Flecking damage


results from the feeding of the larvae primarily F
occidentalis. An economic threshold of one half of
the flowers of tomato infested with F occidentalis
is very conservative and more can be tolerated
under most market conditions (personal observa-
tion). More than 10 adult F tritici or F bispinosa
can be tolerated in tomato without damage. Most
of the halo-spotting and flecking damage in to-
mato and pepper is due to F occidentalis rather
than F bispinosa (Avila et al. 2006; Ghidhui et al.
2006; Salguero Navas et al. 1991b).
Management efforts in central and southern
Florida also are hampered by inadequate knowl-
edge of the population dynamics of Frankliniella
species and 0. insidiosus. Especially lacking is
knowledge of the reproductive status of 0. insid-
iosus during the winter (the females are present
but they may be in reproductive diapause). It is
possible that there are insufficient numbers of the
predator to invade crop fields during Jan and Feb
(J. E. F. personal observation).
In southern Florida, management of F occi-
dentalis needs to be vertically integrated with the
management of another key pepper pest,A. euge-
nii. This will require growers to emphasize sani-
tation and other cultural tactics over broad-spec-
trum insecticides that kill 0. insidiosus or induce
F occidentalis in other ways. Tomato is a poor re-
productive host for F occidentalis, and 0. insidio-
sus does not prefer tomato. The other key pests of
tomato in central and southern Florida are Bemi-
sia tabaci (Gennadius) and the whitefly-transmit-
ted viruses. Ultraviolet-reflective mulch and re-
duced-risk insecticides are examples of tactics
useful in the management ofB. tabaci and F occi-
dentalis. The invasion and establishment ofF. oc-
cidentalis has de-stabilized existing integrated
pest management programs worldwide (Morse &
Hoddle 2006). The vertical integration of its man-
agement with other pests of fruiting vegetables
will be key to the development of effective, sus-
tainable integrated pest management programs
in central and southern Florida.

REFERENCES CITED

DE ASSIS FILHO, F. M., STAVISKY, J. REITZ, S. R., DEOM,
C. M., AND SHERWOOD, J. L. 2005. Midgut infection
by tomato spotted wilt virus and vector incompe-
tence of Frankliniella tritici. J. Appl. Entomol. 129:
548-550.
AVILA, Y., STAVISKY, J., HAGUE, S., FUNDERBURK, J.,
REITZ, S., AND MOMOL, T. 2006. Evaluation of Fran-
kliniella bispinosa (Thysanoptera: Thripidae) as a
vector of Tomato spotted wilt virus in pepper. Florida
Entomol. 89: 204-207.
BAUSKE, E. M., ZEHNDER, G. M., SIKORA, E. J., AND
KEMBLE, J. 1998. Southeastern tomato growers
adopt integrated pest management. HortTechnology
8: 40-44.
BRODBECK, B. V., STAVISKY, J., FUNDERBURK, J. E.,
ANDERSEN, P. C., AND OLSON, S. M. 2001. Flower ni-
trogen status and populations of Frankliniella occi-











dentalis feeding on Lycopersicon esculentum. Ento-
mol. Exp. Appl. 99: 165-172.
DIFFIE, S., FUNDERBURK, J., GOLDARAZENA, A., AND
MOUND, L. 2008. New North American records for
two oriental thrips (Thysanoptera) species. J. Ento-
mol. Sci. 43: 128-132.
EGER, JR., J. E., STAVISKY, J., AND FUNDERBURK, J. E.
1998. Comparative toxicity of spinosad to Franklin-
iella spp. (Thysanoptera: Thripidae), with notes on a
bioassay technique. Florida Entomol. 81: 547-551.
FUNDERBURK, J., STAVISKY, J., AND OLSON, S. 2000.
Predation of Frankliniella occidentalis (Thysan-
optera: Thripidae) in field peppers by Orius insidio-
sus (Hemiptera: Anthocoridae). Environ. Entomol.
29: 376-382.
GHIDUI, G. M., HITCHNER, E. M., AND FUNDERBURK, J.
E. 2006. Goldfleck damage to tomato fruit caused by
the feeding of Frankliniella occidentalis (Thysan-
optera: Thripidae). Florida Entomol. 89: 279-282.
HANSEN, E. A., FUNDERBURK, J. E., REITZ, S. R., RAM-
ACHANDRAN, S., EGER, J. E., AND MCAUSLANE, H.
2003. Within-plant distribution of Frankliniella spe-
cies (Thysanoptera: Thripidae) and Orius insidiosus
(Heteroptera: Anthocoridae) in field pepper. Envi-
ron. Entomol. 32: 1035-1044.
IMMARAJU, J. A., PAINE, T. D., BETHKE, J. A., ROBB, K.
L., AND NEWMAN, J. P. 1992. Western flower thrips
(Thysanoptera: Thripidae) resistance to insecticides
in coastal California greenhouses. J. Econ. Entomol.
85:9-14.
KIRK, W. D. J., AND TERRY, L. I. 2003. The spread of the
western flower thrips Frankliniella occidentalis
(Pergande). Agric. For. Entomol. 5: 301-310.
MOMOL, M. T., OLSON, S. M., FUNDERBURK, J. E.,
STAVISKY, J., AND MAROIS, J. J. 2004. Integrated
management of tomato spotted wilt in field-grown
tomato. Plant Dis. 88: 882-890.
MORSE, J. G., AND HODDLE, M. S. 2006. Invasion biology
of thrips. Annu. Rev. Entomol. 51: 67-89.
MOUND, L. A. 1997. Biological diversity, pp. 197-215 In
T Lewis [ed.], Thrips As Crop Pests. CAB Interna-
tional, New York. 740 pp.
NORTHFIELD, T. D., PAINI, D. R., FUNDERBURK, J. E.,
AND REITZ, S.R. 2008.Annual (:.. I.. .. F, .., .. ......
spp. Thrips (Thysanoptera: Thripidae) abundance on
North Florida uncultivated reproductive hosts: pre-
dicting possible sources of pest outbreaks. Ann. En-
tomol. Soc. America 101: 769-778.
PAINI, D. R., FUNDERBURK, J. E., JACKSON, C. T., AND
REITZ, S. R. 2007. Reproduction of four thrips species
(Thysanoptera: Thripidae) on uncultivated hosts. J.
Entomol. Sci. 42: 610-615.
PAINI, D. R., FUNDERBURK, J. E., AND REITZ, S. R. 2008.
Competitive exclusion of a worldwide invasive pest


March 2009


by a native. Quantifying competition between two
phytophagous insects on two host plant species. J.
Anim. Ecol. 77: 184-190.
PUCHE, H., BERGER, R. D., AND FUNDERBURK, J. E.
1995. Population dynamics of Frankliniella thrips
and progress of tomato spotted wilt virus. Crop Prot.
14: 577-583.
RAMACHANDRAN, S., FUNDERBURK, J., STAVISKY, J., AND
OLSON, S. 2001. Population abundance and move-
ment of Frankliniella species and Orius insidiosus in
pepper. Agric. For. Entomol. 3: 1-10.
REITZ, S. R. 2002. Seasonal and within-plant distribu-
tion of Frankliniella thrips (Thysanoptera: Thripi-
dae) in northern Florida. Fla. Entomol. 85: 431-439.
REITZ, S. R., YEARBY, E. L., FUNDERBURK, J. E.,
STAVISKY, J., MOMOL, M. T., AND OLSON, S. M. 2003.
Integrated management tactics for Frankliniella
thrips (Thysanoptera: Thripidae) in field-grown pep-
per. J. Econ. Entomol. 96: 1201-1214.
ROSELLO, S., DIEZ, M. J., AND NUNEZ, F. 1998. Genetics
of tomato spotted wilt virus resistance coming from
Lycopersicon peruvianum. European J. Plant Pathol.
104: 499-509.
SALGUERO NAVAS, V. E., FUNDERBURK, J. E., BESHEAR,
R. J., OLSON, S. M., AND MACK, T. P. 1991a. Seasonal
patterns ofFrankliniella spp. (Thysanoptera: Thrip-
idae) in tomato flowers. J. Econ. Entomol. 84: 1818-
1822.
SALGUERO NAVAS, V. E., FUNDERBURK, J. E., OLSON, S.
M., AND BESHEAR, R. J. 1991b. Damage to tomato
fruit by the western flower thrips (Thysanoptera:
Thripidae). J. Entomol. Sci. 26: 436-442.
SALGUERO NAVAS, V. E., FUNDERBURK, J. E., OLSON, S.
M., AND BESHEAR, R. J. 1994. Aggregation indices
and sample size curves for binomial sampling of
flower-inhabiting Frankliniella species (Thysan-
optera: Thripidae) on tomato. J. Econ. Entomol. 87:
1622-1626.
STAVISKY, J., FUNDERBURK, J., BRODBECK, B. V., OL-
SON, S. M., AND ANDERSEN, P. C. 2002. Population
dynamics of Frankliniella spp. and tomato spotted
wilt incidence as influenced by cultural management
tactics in tomato. J. Econ. Entomol. 95: 1216-1221.
SRIVISTAVA, M., BOSCO, L., FUNDERBURK, J., OLSON, S.,
AND WEISS, A. 2008. Spinetoram is compatible with
the key natural enemy of Frankliniella species
thrips in pepper. Plant Health Progress doi:10.1094/
PHP-2008-0118-02-RS.
STAVISKY. J., FUNDERBURK, J., BRODBECK, B. V., OL-
SON, S. M., AND ANDERSEN, P. C. 2002. Population
dynamics of Frankliniella spp. and tomato spotted
wilt incidence as influenced by cultural manage-
ment tactics in tomato. J. Econ. Entomol. 95: 1216-
1221.


Florida Entomologist 92(1)







Reitz: Biology and Pest Status of Western Flower Thrips


BIOLOGY AND ECOLOGY OF THE WESTERN FLOWER THRIPS
(THYSANOPTERA: THRIPIDAE): THE MAKING OF A PEST

STUART R. REITZ
USDA-ARS-CMAVE, 6383 Mahan Dr., Tallahassee, FL 32308-1410 USA

ABSTRACT

In the past 30 years, western flower thrips, Frankliniella occidentalis (Pergande) (Thysan-
optera: Thripidae), has become one of the most important agricultural pests worldwide. Cer-
tain biological attributes of this insect predispose it to be a direct pest across a wide range
of crops. In addition to the direct damage it can cause, this species is an efficient vector of To-
mato spotted wilt virus and other Tospoviruses. This review addresses questions regarding
the biological and ecological attributes of western flower thrips that have enabled it to be-
come a significant pest and make it so difficult to manage. These important life history traits
include western flower thrips polyphagy and a tendency to reside and feed in concealed ar-
eas of flowers and fruits. Consequently, large populations can develop and disperse into a
wide range of crops. The larvae and adults feed in a similar manner and can share the same
host plant resources. The relatively short generation time and haplodiploid sex determina-
tion also contribute to the pest status of this species. These life history traits interact in com-
plex ways to make western flower thrips one of the most significant and difficult to manage
pests in the world.

Key Words: Frankliniella occidentalis, Tospovirus, behavioral ecology, pest status

RESUME

En los pasados 30 aios, el trips occidental de las flores, Frankliniella occidentalis (Pergande)
(Thysanoptera: Thripidae), se ha convertido en una de las plagas mas importantes de la
agriculture mundial. Ciertos atributos biol6gicos de este insecto lo predispone para ser una
plaga direct por un rango amplio de cultivos. Ademas del daio director que causa, esta es-
pecie es un vector eficiente del virus de la marchitez manchada del tomatey otros Tospovirus.
Este resume se dirije a las preguntas sobre los atributos biol6gicos y ecol6gicos del trips oc-
cidental de las flores que le han permitido llegar a ser una plaga significant y hacerla tan
dificil de controlar. Estas importantes caracteristicas de su historic de vida incluyen la poli-
fagia del trips occidental de las flores y su tendencia para morar y alimentarse en areas ocul-
tas de flores y frutos. Por consiguiente, grandes poblaciones pueden desarrollarse y
dispersarse en un rango amplio de cultivos. Las larvas y adults se alimentan en una ma-
nera similar y pueden compartir los recursos de la misma plant. El period de generaci6n
relativamente corto y la determinaci6n haplodiploide de los sexos tambi6n contribuyen al es-
tatus de plaga de esta especie. Estas caracteristicas de su ciclo de vida se relacionan de una
manera compleja para hacer que el trips occidental de las flores sea una de las plagas mas
significantes y dificiles para manejar en el mundo.


Over the past 30 years, western flower thrips,
Frankliniella occidentalis (Pergande) (Thysan-
optera: Thripidae), has become one of the most
important agricultural pests worldwide. It is ar-
guably the most studied thrips in the world today.
The increasing importance of western flower
thrips is clearly reflected by the increasing num-
ber of publications on this species relative to the
proportion of publications on all Thysanoptera
(Fig. 1). There are over 5,000 species of thrips, yet
western flower thrips alone has accounted for one
third of the publications on all Thysanoptera in
the past 30 years.
This increasing interest in western flower
thrips is a result of its significance as an agricul-
tural pest, which raises the question of what has
enabled it to become such a pest. Its pest status
can be attributed to several factors, including its


reproductive potential, invasiveness, range of
host crops, ability to transmit plant viruses, and
insecticide resistance. All of these factors are in-
terrelated, and all are related to the basic life cy-
cle and life history strategy of the species. This re-
view addresses the biological and ecological at-
tributes of western flower thrips that have en-
abled it to become a significant, difficult to
manage pest. Many other species of Thripidae
share these attributes of western flower thrips
and therefore could emerge as significant pests.

Biology of Western Flower Thrips

The general life cycle of western flower thrips
is similar to that of other species in the family
Thripidae, consisting of an egg, 2 active feeding
larval instars, 2 relatively quiescent pupal in-







Florida Entomologist 92(1)


S *
)U









O0 I- -
5 +





0 ....mw*m"
1974 1978 1982 1986 1990 1994 1998 2002 2006


* Thrips
, Western Flower Thrips


Year
Fig. 1. Trends in the number of peer-reviewed journal publications on thrips in general and the western flower
thrips in particular since 1974. Data are derived from searching the Web of Science@ (http://apps.isiknowl-
edge.com). A search for publications with the topic "thrips" or "Thysanoptera" was conducted to find publications on
thrips in general. A second search for publications with the topic "Frankliniella occidentalis" or "western flower
thrips" was conducted to locate publications specifically addressing F occidentalis.


stars, and the adult. Adults and larvae aggregate
in flowers or other concealed areas on plants, such
as developing fruits, foliage, and floral buds
(Hansen et al. 2003). This preference for residing
in tightly enclosed and concealed spaces of plants
is termed thigmotactic behavior. Females have a
saw-like ovipositor, which they use to deposit eggs
into leaves, petioles, flower bracts and petals, and
developing fruit.
Sex determination in the western flower thrips
is through haplodiploidy. The haploid males are
produced from unfertilized eggs, whereas the dip-
loid females are produced from fertilized eggs (ar-
rhenotoky) (Moritz 1997). Although sex ratios of
adults from field samples are often biased to-
wards 1 sex or the other, mated females do not ap-
pear to allocate the sex of their progeny (Terry &
Kelly 1993). Therefore, biases found in those
adult sex ratios are likely a function of differences
between the sexes in their dispersal, distribution
in response to host quality, and longevity.
Development is temperature and host depen-
dent but can be quite rapid, allowing multiple
generations to occur in a single cropping season.
Western flower thrips does not have an obligatory
developmental or reproductive diapause (Ishida
et al. 2003). Therefore, development occurs when-
ever temperatures exceed a minimum threshold
of 8-10C (Katayama 1997; McDonald et al. 1998).
At the most favorable temperatures of 25-30C,
egg to adult development time can be as brief as
9-13 d (Lublinkhof & Foster 1977; Robb 1989;
Gaum et al. 1994; Katayama 1997; Reitz 2008).


The duration of the egg stage is relatively long,
with hatching in 2-4 d at optimal temperatures.
The first stadium is typically about half the
length of the second (Gaum et al. 1994; Reitz
2008), after which feeding stops and pupation be-
gins. Thrips often drop to the soil to pupate, but
significant numbers can remain on host plants,
especially if hosts have complex floral architec-
ture (Broadbent et al. 2003; Buitenhuis & Shipp
2008). The first pupal instar is termed the prop-
upa, a non-feeding stage that is followed by the
pupa, another non-feeding pupal stage. Winged
adults then emerge from the pupal stage in 1-3 d.
Under laboratory conditions, adult lifespan is
relatively long compared with immature develop-
ment time. For example, at 28C, median egg to
adult development time is 12 d, whereas median
longevity for females is 26 d (Reitz 2008), with
some females living up to 5 weeks (Trichilo &
Leigh 1988; Hulshof & Vanninen 2002; Zhi et al.
2005; Reitz 2008). The relevance of these data to
actual longevity in the field is unclear, but over-
lapping, continuous generations are likely to oc-
cur in the field. Although determining longevity
in the field is problematic with such small vagile
insects, mark-recapture studies indicate that
adults can survive for over 5 d following release in
pepper and tomato plantings (unpublished data).
Western flower thrips feed by piercing plant
cells with their mouthparts and sucking out the
contents (Hunter & Ullman 1989; Harrewijn et
al. 1996). Adults and larvae feed in a similar man-
ner, so both stages contribute to plant damage. In-


March 2009







Reitz: Biology and Pest Status of Western Flower Thrips


dividuals tend to feed in localized areas, which re-
sults in silvered or necrotic patches on foliage,
flowers and fruit. Feeding within developing buds
leads to deformation of leaves or flowers (Childers
1997). Western flower thrips also feeds on pollen
(Trichilo & Leigh 1988), which can stimulate ovi-
position, reduce larval development time, and in-
crease female fecundity (Hulshof & Vanninen
2002; Hulshof et al. 2003; Zhi et al. 2005; Riley et
al. 2007). Although primarily phytophagous,
adults and larvae will prey on spider mite eggs
(Trichilo & Leigh 1986).
Western flower thrips fits the classic definition
of an r-selected species (Pianka 1970; Reitz 2008).
All studies of reproduction in western flower
thrips have reported high fecundity for females.
After an initial preoviposition period, a female
can oviposit throughout her lifetime (Reitz 2008).
With optimal temperatures and diets, females
can produce up to 7 progeny per day and have av-
erage total lifetime fecundities exceeding 200 per
female (Robb & Parrella 1991). This high level of
fecundity leads to high intrinsic rates of popula-
tion increase, so uncontrolled populations can
multiply rapidly (Gaum et al. 1994; Gerin et al.
1994; Hulshof et al. 2003).
One of the most important aspects of western
flower thrips biology is its polyphagy. This species
is known to feed on over 250 different crop plants
from more than 60 plant families (Robb 1989;
Tommasini & Maini 1995; Lewis 1997). In addi-
tion, it occurs on many uncultivated plants
(Chellemi et al. 1994; Paini et al. 2007). However,
it is critical to distinguish between plant species
that support successful reproduction and those on
which adults feed but do not support successful
breeding populations (Mound 2005). Paini et al.
(2007) found that the range of adult feeding hosts
in northern Florida is broader than the range of
reproductive hosts, emphasizing the need to look
beyond static records of plant associations to un-
derstand the ecology and population dynamics of
western flower thrips. To avoid misunderstand-
ings and misinterpretations, it is clear that the
term "host plant" must be applied in the proper
context.
Because of its polyphagous feeding and breed-
ing behavior, western flower thrips is exposed to a
broad diversity of plant allelochemicals (Feyere-
isen 1999). Therefore, it must be able to metabo-
lize a broad range of allelochemicals, as well as
produce inducible enzymes in response to specific
compounds (Li et al. 2007). Unfortunately, there
is little basic ecophysiology information on the re-
sponse of western flower thrips to host plant
chemistry. Based on pesticide resistance studies,
western flower thrips has various metabolic
detoxification enzyme systems that could help it
to overcome secondary plant defenses (Jensen
2000; Espinosa et al. 2005). Chief among these
systems are cytochrome P-450 monooxygenases,


esterases, and glutathione S-transferases. Ap-
parently, this generalist herbivore has many alle-
lochemical-metabolizing genes to enable it to cope
with the diversity of allelochemicals that it is
likely to encounter (Li et al. 2007).

Western Flower Thrips as a Pest

Beginning in the late 1970s, western flower
thrips began to spread widely from its native
range in western North America (Kirk & Terry
2003). The exact cause for its spread is uncertain
but increased global trade in floricultural and
horticultural products has been implicated. A
highly insecticide resistant strain originated in
California as a result of intensive insecticide use
in greenhouse crops in the 1970s and 1980s (Robb
1989; Immaraju et al. 1992). Western flower
thrips is now established throughout North
America, and many countries of Europe, Asia,
South America, Africa, and Australia (Kirk &
Terry 2003).
Whereas human assisted movement is un-
doubtedly responsible for many of the introduc-
tions of western flower thrips to new geographic
areas, this species is also able to spread by other
means within new areas (Kirk & Terry 2003).
Thrips can move long distances on wind currents
(Mound 1983). Spread is further enhanced by
polyphagy and the ability of small founder popu-
lations to succeed. Several biological factors make
western flower thrips an ideal invasive species to
be spread by human activity. The small size and
thigmotactic behavior of larvae and adults make
detection difficult. In addition, because eggs are
deposited within plant tissue, they are even less
readily detected, and are less susceptible to fumi-
gation than are other life stages (MacDonald
1993; Janmaat et al. 2002; Simpson et al. 2007).
The polyphagous nature of western flower thrips
increases the number of crops on which it may be
exported from a country, and then enhances the
probability of introduced individuals finding suit-
able hosts in new areas (Morse & Hoddle 2006).
The high fecundity of females makes it possible
for small founder populations to become estab-
lished and grow rapidly. Further, the haplodiploid
sex determination leads to strong selection
against deleterious alleles in the haploid males
(Denholm et al. 1998). Consequently, some small
founder populations may readily adapt to new en-
vironments and be relatively resistant to the det-
rimental effects of inbreeding (Schmid-Hempel et
al. 2007). Also, because of their potentially long
adult lifespan, rapid immature development rate,
and haplodiploid sex determination, unmated
founder females could produce male progeny ini-
tially and survive long enough to mate with those
males, thus making introduced populations as
small as one potentially viable (Immaraju et al.
1992).







Florida Entomologist 92(1)


The sheer number of crops that western flower
thrips attacks is astounding. It is a significant
pest of virtually all crops, including fruiting vege-
tables, leafy vegetables, ornamentals, tree fruits,
small fruits, and cotton (Lewis 1997). The range of
crops damaged by western flower thrips is simply
a reflection of its inherent polyphagy. Direct crop
damage results from both feeding and oviposition
(Childers 1997). In addition, high fecundity and
reproduction on a broad range of hosts enables
large numbers to disperse into crop fields from
many sources. Consequently, attempting to man-
age the sources of thrips is virtually impossible.
In many floral and horticultural crops, western
flower thrips populations are virtually guaran-
teed to exceed the low to non-existent damage
thresholds (Robb & Parrella 1991).
Adult and larval feeding causes considerable
aesthetic damage to ornamental and fruiting
crops (Parrella & Jones 1987). Extensive feeding
can also result in flower and fruitlet abortion,
which is a direct yield loss (Childers 1997). Be-
cause of their thigmotactic behavior, feeding dam-
age is often inflicted on developing tissue, which
then goes undetected until flowers or fruit mature
(Welter et al. 1990; Pearsall 2000; Steiner &
Goodwin 2005; Ghidiu et al. 2006). Not all crops
damaged by western flower thrips are reproduc-
tive hosts for the species. Those that only serve as
adult feeding hosts, for example tomato (Brod-
beck et al. 2001), can still be adversely affected by
adult feeding.
Further complicating management, western
flower thrips feeding damage can be confused
with damage caused by other pests or diseases
(Steiner & Goodwin 2005). Such incorrect diag-
noses may result from the small size and cryptic
habits of western flower thrips and the fact that
damage is not immediately apparent and associ-
ated with the causal organism. Unfortunately,
misdiagnoses often lead to inappropriate pesti-
cide application.
Female oviposition causes another type of
damage to developing fruits. Females insert eggs
under plant epidermis with their saw-like ovipos-
itor. This wounding elicits a physiological wound
response in some plants that produces spotting on
fruits. Extensive spotting can lead to downgrad-
ing of quality in tomatoes (Salguero-Navas et al.
1991), grapes (Jensen 1973) and apple (Terry &
De Grandi-Hoffman 1988), among other crops.
By far the greatest damage caused by western
flower thrips is its ability to transmit Tospovi-
ruses. Western flower thrips is known to vector 5
Tospovirus species, 2 of which, Tomato spotted
wilt virus (TSWV) and Impatiens necrotic spot vi-
rus, occur in the United States (Whitfield et al.
2005). Although accurate data are difficult to ob-
tain, an estimate that TSWV alone causes over $1
billion in losses annually has been reported (Gold-
bach & Peters 1994).


Over 1,000 species of plants in 84 families are
susceptible to TSWV (Parrella et al. 2003), giving
it one of the broadest host ranges of any plant
pathogen. In 2 ways, this broad host range is
clearly related to the distribution of its main vec-
tor, western flower thrips. First, because western
flower thrips can reproduce on many different
plants, viruliferous adults arise from many differ-
ent sources. Given the fecundity of western flower
thrips, large numbers of viruliferous individuals
can be present in the environment at any time.
Further, different source plants can harbor vari-
ous strains of the virus, which further complicates
the development of effective disease management
programs (Ullman et al. 2002). Second, suscepti-
ble crops do not need to be reproductive hosts for
the thrips because adults retain and transmit the
virus throughout their lives (Ullman et al. 1993)
and can feed on a wider range of plants than they
use for reproduction (Paini et al. 2007). For exam-
ple, most tomato spotted wilt in field grown to-
mato is a result of primary spread of the pathogen
from viruliferous adults dispersing into the fields
(Puche et al. 1995). Tomato is a poor reproductive
host for western flower thrips (Brodbeck et al.
2001; Reitz 2002). In fact, it may be possible for
epidemics of tomato spotted wilt to be greater in
less preferred hosts if viruliferous individuals are
more likely to feed briefly, but long enough for
transmission to occur, and then move from plant
to plant (Reitz 2005). Western flower thrips has
an intimate, complex relationship with these vi-
ruses. For a western flower thrips to transmit
TSWV, it must acquire the virus as a larva, pri-
marily as a first instar (Tsuda et al. 1996; van de
Wetering et al. 1996). Western flower thrips may
acquire TSWV as an adult, but such individuals
do not become competent vectors (de Assis Filho
et al. 2004). Second instars are physiologically ca-
pable of transmitting the virus (Wijkamp & Pe-
ters 1993), but as they do not readily move from
plant to plant, transmission is essentially re-
stricted to vagile adults. Transmission can occur
quite rapidly, in as little as 5 min of feeding
(Wijkamp et al. 1996). The short time needed for
transmission contributes to the ineffectiveness of
insecticides to limit the spread of TSWV.
Because of the severe threat posed by western
flower thrips, there has been a heavy reliance on
insecticides for its management. However, the
thigmotactic nature of this species limits its di-
rect exposure to insecticides. For open field crops,
the numerous reproductive hosts, high fecundity
and rapid generation time of western flower
thrips result in a constant influx of new immi-
grants which even repeated insecticide applica-
tions cannot successfully control (Bauske 1998).
Perhaps the most important problem with in-
secticide use is the ability of western flower thrips
to develop resistance to insecticides. The first re-
ported insecticide failure against western flower


March 2009







Reitz: Biology and Pest Status of Western Flower Thrips


thrips was in 1961 and, since then, there have
been numerous documented cases of resistance to
most classes of insecticides around the world
(Jensen 2000). The extensive resistance found in
California greenhouse populations (Immaraju et
al. 1992) has been implicated as a contributing
factor in the worldwide spread of western flower
thrips (Kirk & Terry 2003).
The polyphagous nature of western flower
thrips plays a key role in its ability to develop re-
sistance to insecticides. Because it is a pest of
many crops, populations are often under constant
insecticide pressure, which increases selection for
resistance. Enclosed greenhouse environments
also place populations under intense selection for
resistance because they provide constant expo-
sure to insecticides and limit immigration of sus-
ceptible individuals (Robb & Parrella 1991; Im-
maraju et al. 1992; Denholm et al. 1998).
The haplodiploid sex determination system in
western flower thrips greatly accelerates the evo-
lution of insecticide resistance (Denholm et al.
1998). In haplodiploid species, resistance genes
are exposed to selection from the outset in haploid
males, regardless of whether resistance alleles
are dominant or recessive. Thus, resistance alle-
les can become fixed much more rapidly than if
western flower thrips were diploid. Not only can
western flower thrips evolve resistance rapidly,
resistance can persist over many generations in
the absence of selection (Robb 1989; Br0dsgaard
1994; Bielza et al. 2008b). Even more troubling
for resistance management programs is recent ev-
idence that resistance to certain insecticides (i.e.,
acrinathrin and spinosad) does not come with a
fitness cost to western flower thrips (Bielza et al.
2008a). Consequently, resistance could evolve
faster and be maintained in populations longer,
which would greatly affect the development and
viability of insecticide rotation schemes and resis-
tance management programs. As a polyphagous
herbivore, western flower thrips has evolved nu-
merous metabolic detoxification pathways to con-
tend with diverse plant allelochemicals that it en-
counters. These versatile enzymatic systems pre-
dispose it to be able to metabolize many insecti-
cides (Jensen 2000) and often confer cross-
resistance to other insecticides (Br0dsgaard 1994;
Espinosa et al. 2002). Metabolic detoxification en-
zymes such as cytochrome P450 monooxygenases,
glutathione S-transferases, and esterases have
been implicated as contributing to insecticide re-
sistance in various western flower thrips popula-
tions (Jensen 2000). The major detoxification
pathway appears to be through metabolism of
toxicants by cytochrome P450 monooxygenases
(Espinosa et al. 2005). These enzymes are known
to confer resistance and cross-resistance to pyre-
throids, organophosphates, and carbamates.
Western flower thrips is clearly a formidable
pest because of the range of crops it attacks


throughout the world, the ever increasing amount
of damage caused by its feeding, oviposition and vi-
rus transmission, and the propensity with which it
develops insecticide resistance. While much has
been learned about this species and how to manage
it (see the other papers in this symposium), there is
a clear need to continue development of more eco-
nomically and environmentally sustainable man-
agement strategies for this devastating pest. To
better manage this species, a greater understand-
ing is needed of its biological and ecological at-
tributes especially its biology, ecology and popula-
tion dynamics outside of cropping systems. As for-
midable a problem as the western flower thrips has
become, other thrips with similar biological and
ecological attributes exist and could, likewise, rap-
idly emerge as serious global pests (Kirk & Terry
2003). Thus, increased knowledge about western
flower thrips will help to avoid or mitigate damage
due to other pest thrips.

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VAN DE WETERING, F., GOLDBACH, R., AND PETERS, D.
1996. Tomato spotted wilt tospovirus ingestion by
first instar larvae of Frankliniella occidentalis is a
prerequisite for transmission. Phytopathol. 86: 900-
905.
WHITFIELD, A. E., ULLMAN, D. E., AND GERMAN, T. L.
2005. Tospovirus-thrips interactions. Annu. Rev.
Phytopathol. 43: 459-489.
WIJKAMP, I., AND PETERS, D. 1993. Determination of the
median latent period of two tospoviruses in Fran-
kliniella occidentalis, using a novel leaf disk assay.
Phytopathol. 83: 986-991.
ZHI, J., FITCH, G. K., MARGOLIES, D. C., AND NECHOLS,
J. R. 2005. Apple pollen as a supplemental food for
the western flower thrips, Frankliniella occidentalis:
Response of individuals and populations. Entomol.
Exp. Appl. 117: 185-192.
WIJKAMP, I., VAN DE WETERING, F., GOLDBACH, R., AND
PETERS, D. 1996. Transmission of tomato spotted
wilt virus by Frankliniella occidentalis: median ac-
quisition and inoculation access period. Ann. Appl.
Biol. 129: 303-313.







Florida Entomologist 92(1)


March 2009


MANAGEMENT OF FLOWER THRIPS IN BLUEBERRIES IN FLORIDA


H. ALEJANDRO AREVALO1, AIMEE B. FRAULO1 AND OSCAR E. LIBURD
Entomology and Nematology Department, University of Florida/IFAS, Gainesville, FL

'Current Address: Entomology and Nematology Department. University of Florida/IFAS, Southwest Florida
Research and Education Center, Immokalee, FL

ABSTRACT

Flower thrips are considered key pests in southern highbush (Vaccinium corymbosum L.
x V darrowi Camp) and rabbiteye (Vaccinium ashei Reade) blueberry fields in Florida.
During 2005 and 2006, we evaluated the effectiveness of selected natural enemies (pre-
ventative and curative releases) for control of flower thrips in blueberries. Experimental
designs were randomized complete blocks with 4 treatments and 4 replicates in 2005 and
3 treatments and 4 replicates in 2006. In 2005, treatments were evaluated as a preven-
tative tactic and included the following biological control agents: (1) Thripor-I [Orius in-
sidiosus Say (Hemiptera: Anthocoridae)], (2) Thripex-plus [Amblyseius cucumeris
(Oudemans) (Acari: Phytoseiidae)], (3) combination of both 0. insidiosus and A. cucum-
eris in 50% of standard dosages, and (4) untreated control (no natural enemies). Orius.
insidiosus (Thripor-I) was released at 0.5 insects per m2 andA. cucumeris (Thripex-Plus)
at 0.5 sachets of 1000 mites per m2. For the combination treatment, 50% of each standard
dosage was released. In 2006, treatments were evaluated as a curative technique and in-
cluded (1) Thripor-I (0. insidiosus) released at 10 insects per m2, (2) Thripex-Plus, and
(3)control [no natural enemies were released]. In 2005, the results indicated that thrips
populations in the control were on average significantly lower than in treatments of O.
insidiosus and A. cucumeris alone, implicating the potential for intraguild predation
among natural enemies. In 2006, there were no significant differences among the treat-
ments evaluated probably due to the short duration of time during which flower thrips
are present in blueberry fields.

Key Words: Frankliniella tritici, Frankliniella occidentalis, southern highbush, rabbiteye
blueberries, natural enemies, Orius insidiosus, Amblyseius cucumeris, biological control

RESUME

Se consideran los trips de las flores como una plaga clave de los arandanos "southern hig-
hbush" (Vaccinium corymbosum L. x V darrowi Camp) y rabbiteyee" (Vaccinium ashei
Reade) en los campos de arandano en la Florida. Durante los anos 2005 y 2006, nosotros
evaluamos la efectividad de enemigos naturales seleccionados (liberaciones preventivas
y curativas) para el control de trips de las flores en arandano. Los disehos experimenta-
les fueron bloques completamente aleatorizados con 4 tratamientos y 4 replicas en el aio
2005 y 3 tratamientos y 4 replicas en el ano 2006. En 2005, los tratamientos fueron eva-
luados como una tactica preventive e incluyeron los agents de control biol6gicos si-
guientes: (1) Thripor-I [Orius insidiosus Say (Hemiptera: Anthocoridae)], (2) Thripex-
plus [Amblyseius cucumeris (Oudemans) (Acari: Phytoseiidae)], (3) una combinaci6n de
ambos 0. insidiosus yA. cucumeris en 50% de la dosis estandar, y (4) un control no tra-
tado (sin enemigos naturales). Orius. insidiosus (Thripor-I) fue liberado al 0.5 insects
por m2 yA. cucumeris (Thripex-Plus) al 0.5 sobrecitos con 1000 mites por m2. Para el tra-
tamiento de combinaci6n, 50% de cada dosis estandar fue liberada. En el 2006, los tra-
tamientos fueron evaluados como una t6cnica curativa e incluyeron (1) Thripor-I (0.
insidiosus) liberado unos 10 insects por m2, (2) Thripex-Plus, y (3) el control [sin enemi-
gos naturales liberados]. En el 2005, los resultados indicaron que la poblaci6n de los
trips en el control por lo general fue mas baja que en los tratamientos con solo 0. insi-
diosus yA. cucumeris, que implica el potential de depredaci6n entire los miembros de es-
tos enemigos naturales asociados. En el 2006, no habian diferencias significativas entire
los tratamientos evaluados probablemente debido a la corta duraci6n del tiempo durante
lo cual los trips de las flores estan presents en los campos de arandano.


Flower thrips belong to the family Thripidae within the floral structures of cultivated and wild
within the order Thysanoptera. The majority of plants and are pests of cultivated berries in Flor-
flower thrips belong to the genera Franklinella ida. To date, there is no evidence that flower
and Thrips. Flower thrips feed and reproduce thrips vector any viruses to berry crops in Florida,







Arevalo et al.: Management of Flower Thrips in Florida Blueberries


but they are known to reduce the quality and
quantity of the fruit produced. The small size and
cryptic nature of the eggs and larvae make thrips
difficult to monitor and control in an agricultural
system. The transportation of agricultural prod-
ucts such as whole plants, cut flowers, fruits, and
vegetables facilitates regional and international
dispersal of flower thrips. In addition, Parrella &
Lewis (1997) explain that small insects such as
thrips use the convective upper wind currents to
disperse long distances. Natural dispersal occurs
when plant quality decreases or local weather
conditions are not conducive for population
growth.
Flower thrips are considered key pests in
southern highbush (Vaccinium corymbosum L. x
V darrowi Camp) and rabbiteye (Vaccinium ashei
Reade) blueberry fields in Florida and southern
Georgia (Arevalo 2006; Liburd et al. 2006) and a
secondary pests in strawberries in Florida (Price
et al. 2006; Rondon et al. 2005). In blueberries,
flower thrips prefer to oviposit on the petals, but
the damage to the berry occurs when they oviposit
and feed on the ovaries (Arevalo & Liburd 2007a).
In Florida, the dominant species attacking blue-
berries is Frankliniella bispinosa (Morgan), ac-
counting for ~93% of the thrips captured on sticky
traps or collected from within blueberry flowers
(Arevalo & Liburd 2007a). In strawberries, an as-
semblage of species, F bispinosa and F occiden-
tallis feed on the floral tissues causing Type 1
bronzing on the fruit (Rondon et al. 2005; Zalom
et al. 2008).
In many crops, thrips populations are regulated
by natural enemies including Orius insidiosus
(Say), Geocoris spp, and Chalcidoidae parasitoids
among others (Mossler & Nesheim 2007; Rondon
et al. 2005). Fraulo et al. (2008) found that Chalci-
doidae wasp populations were higher in plots with
high numbers of thrips. Here we evaluate the po-
tential ofO. insidiosus andA. cucumeris alone, and
in combination as biological control tactics to pre-
vent or to reduce flower thrips populations in
southern highbush blueberries in Florida.

MATERIALS AND METHODS

In 2006, we evaluated the natural enemies as a
curative technique for the control of flower thrips
because attempts at preventative control for
flower thrips were not effective in 2005. A new
randomization of all 4 treatments was evaluated
during the 2006 trials. In addition, we increased
the release rates in an attempt to increase treat-
ment effectiveness. The following treatments
were evaluated in 2006: (1) Thripor-I (0. insidio-
sus) released at 10 insects per m2, (2) Thripex-
Plus (A. cucumeris) evaluated at 1.3 sachets of
1000 mites per m2, (3) combination of both O. in-
sidiosus andA. cucumeris in 50% of curative dos-
ages, and (4) control in which no natural enemies


were released. All treatments were released on 15
Feb when the number of thrips on sticky traps
was above 100 thrips per trap. Biological control
trials were located at a commercial farm in north-
central Florida (N 28054' W 8214). This farm is
planted with southern highbush blueberries,
which consist of mixed varieties of Star, Jewel,
Emerald, and Millennia. Bushes were ~1.5 m tall
and spaced ~1 m apart. The experimental design
to evaluate the effectiveness of selected natural
enemies was a randomized complete block with 4
treatments and 4 replicates in 2005 and 3 treat-
ments and 4 replicates in 2006. The farm was di-
vided in 16 plots (each plot ~70 m2) arranged in 4
blocks (283 m2 per block) in 2005. In 2006, only 12
plots (same size as 2005) were used. There were
buffer zones of 17 m between blocks and 5 m be-
tween plots within a block. During 2005, treat-
ments were evaluated as a preventative tactic
and included the following biological control
agents that were obtained from Koppert Biologi-
cal Systems Romulus, MI: (1) Thripor-I [Orius in-
sidiosus Say (Hemiptera: Anthocoridae)],(2)
Thripex-plus [Amblyseius cucumeris (Oudemans)
(Acari: Phytoseiidae)], (3) combination of both O.
insidiosus and A. cucumeris in 50% of standard
dosages, and (4) untreated control. All dosages
were recommended by the supplier (Koppert Bio-
logical Systems Romulus, MI). Orius insidiosus
(Thripor-I) was released at 0.5 insects per m2 and
A. cucumeris (Thripex-Plus) at 0.5 sachets of 1000
mites per m2. For the combination treatment, we
released 50% of each standard dose. In 2005, nat-
ural enemies were released preventatively 1 week
after flowering began and before thrips popula-
tion begin to increase to form "hot-spots" (Arevalo
& Liburd 2007b). Orius insidiosus and A. cucum-
eris are known to be able to survive in the absence
of prey by feeding on pollen, mites, insects, and
eggs and other secondary prey before thrips ar-
rive to the system (Kiman et al. 1985; Van Rijn et
al. 1993; Van Rijn et al. 1999).
During both years, SpinTor@ 2SC (spinosad)
(DowAgrosciences. Indianapolis, IN) was sprayed
at 105 g a.i. / ha (using a backpack sprayer) in the
buffer zones to discourage the movement of natu-
ral enemies between plots. Since the objective was
to manage thrips populations and encourage nat-
ural enemy activity inside the research plots,
these were not sprayed with insecticides. A white
sticky trap (Great Lakes IPM, Vestaburg, MI) was
placed in the center of each plot to monitor thrips
activity. Each week the traps were collected from
the field and brought to the University of Florida,
Small Fruit and Vegetable IPM laboratory in
Gainesville to count the number of thrips cap-
tured. In addition, a sample of 5 flower-clusters
was collected weekly from each plot and processed
by the "shake and rinse" method described in
Ar6valo & Liburd (2007b) to assess thrips popula-
tion inside the flowers.







Florida Entomologist 92(1)


Statistical Analysis

In 2005, we compared the population of flower
thrips on each of the sampling dates using one-
way ANOVA (SAS Institute Inc. 2002). Treatment
means were separated by LSD (a = 0,05) to deter-
mine differences (SAS Institute Inc. 2002). In
2006, we analyzed the growth rate (r) by compar-
ing the increment of thrips population 1 week af-
ter the release, and 2 weeks after the release of
natural enemies, with the initial population of
thrips before the release.

RESULTS AND DISCUSSION

The trials conducted in 2005 (preventative re-
lease), indicated that releases of 0. insidiosus or
A. cucumeris, as well as the combination of both
treatments as a preventative tactic did not reduce
thrips populations in blueberries during the flow-
ering period (Fig. 1). Data collected from sticky
traps indicated that thrips populations in the con-
trol were on average significantly lower than in
treatments of 0. insidiosus or A. cucumeris alone.
However, no significant differences were detected
between the control and the combination treat-
ment during the first and second weeks after re-
lease (Fig. 1).
During the last week of sampling we captured
significantly fewer thrips in sticky traps in the
control treatment than in any of the other treat-
ments (F = 7.95; df= 3, 9; P = 0.0067). The reasons
why the control had less thrips than the areas
treated with natural enemies is unclear; however,
it may be related to the release of natural enemies
before there was an abundance of thrips (< less
than 10 thrips per trap or flower) in the field. The


300

1 20 4

150

z 00


28-Jan 4-Feb I-Feb I8-Feb 25-Feb
Dte
Fig. 1. Average number of thrips captured per week
after the release of natural enemies, as a preventive
measure, in white sticky traps located inside the blue-
berry bush in 2005. Treatments followed by the same
letter are not significantly different when compared by
LSD (a = 0.05). The arrow represents the date of re-
lease. 4 Feb 2005 (F = 1.52; df = 3, 9; P = 0.62), 11 Feb
2005 (F = 7.13; df = 3, 9; P = 0.016), 18 Feb 2005 (F =
2.83; df = 3, 9; P = 0.0988), 25 Feb 2005 (F = 7.95; df =
3, 9; P = 0.0067)


lack of prey (thrips) may have encouraged some
level of intraguild predation, as well as feeding on
other natural predators in the system and subse-
quently allowing for the increase of thrips popula-
tions in the treated area. Due to the low popula-
tion of thrips in 2005, we were not able to collect
enough thrips from inside the flowers to make a
statistically robust analysis.
Data from the curative releases of 0. insidio-
sus, and A. cucumeris did not show a significant
effect on thrips population (Fig. 2). These results
are consistent with observations made by Mound
& Teulon (1995) and by Parella & Lewis (1997).
These authors concluded that the biological char-
acteristics of thrips overcome the attributes of
natural enemies in such a way that the participa-
tion of natural enemies in the regulation of field
populations of thrips is minor. Other authors ar-
gue that the use of natural enemies is enough to
control thrips populations (Shipp & Wang 2003;
Van de Veire & Degheele 1995). Our preliminary
laboratory observations and other related studies
published showed that Orius spp. and A. cucum-
eris are efficient in controlling flower thrips (Ja-
cobson 1997; Shipp et al. 2003; Van de Veire et al.
1995). However, the observations related to the
success of natural enemies controlling thrips have
been conducted under greenhouse or laboratory
conditions.
One of the few successes in control of flower
thrips under field conditions was reported by
Funderburk et al. (2000), who showed that field
peppers that were untreated or treated with spi-
nosad had a significantly higher population of
Orius spp. and lower population of flower thrips
than fields treated with acephate and fenopro-
pathrin, which excluded predators, mainly O. in-


0-
8-Feb 15-Feb 22-Feb 1-Mar
Date
Fig. 2. Average number of thrips captured per week
after the release of natural enemies, as curative mea-
sure, on white sticky traps located inside the blueberry
bush in 2006. The arrow indicates the date of the re-
lease of natural enemies. No significant differences
among treatments when compared by LSD (a = 0.05).
15 Feb 2006 (F = 0.95; df= 3, 9;P = 0.4549), 22 Feb 2006
(F = 0.54; df= 3, 9;P = 0.6639), 1 Mar 2006 (F = 1.79; df
= 3, 9;P=0.2185).


March 2009







Arevalo et al.: Management of Flower Thrips in Florida Blueberries


sidiosus. However, in these studies the reduction
in the thrips population due to the presence of
natural enemies was observed from 55 and 60 d
after transplanting, approximately 10 d after the
first sampling. These periods of time allowed the
natural enemies to build-up their population, and
have a significant effect on the thrips population.
The situation in blueberries is different. Flower
thrips arrive to the fields after the winter when
the flowers are opening and insect activity in the
foliage is limited. Thrips are only present for an
average for 20 to 25 d, which correspond to the
flowering period in blueberries. This short period
of time may not be long enough for the natural en-
emies to establish and reach a significant level of
control.
Under these experimental conditions we found
that inundative releases of 0. insidiosus, A. cu-
cumeris, both preventatively and curatively, do
not appear to play a significant role in regulating
flower thrips populations in the blueberry system
in Florida. The use of trade names in this publica-
tion is to provide specific information. UF/IFAS
does not guarantee or warranty the products
names, and the references in this publication do
not signify our approval and exclusion of other
products of suitable composition, nor the endorse-
ment of any of the products here included.

ACKNOWLEDGMENTS

We thank Donna Miller for allowing us to use her
farm to conduct biological control studies. We thank the
staff at the Small Fruit and Vegetable IPM Laboratory
at the University of Florida for assistance in processing
samples. We thank Howard Frank for reviewing earlier
drafts of this manuscript. The study was supported by
EPA project X8-964244050 and SARE RD309055 /
9820107.

LITERATURE CITED

AREVALO, H. A. 2006. A Study of the Behavior, Ecology,
and Control of Flower Thrips in Blueberries towards
the Development of an Integrated Pest Management
(IPM) Program in Florida and Southern Georgia.
MS Thesis/PhD dissertation. University of Florida.
Gainesville, FL
AREVALO, H. A., AND LIBURD, O. E. 2007a. Flower
thrips, oviposition and dispersion behavior in early
season blueberries. J. Insect. Sci. 7: 28
AREVALO, H. A., AND LIBURD, O. E. 2007b. Horizontal
and vertical distribution of flower thrips in south-
ern highbush and rabbiteye blueberry plantings,
with notes on a new sampling method for thrips in-
side blueberry flowers. J. Econ. Entomol. 100: 1622-
1632.
FRAULO, A. B., MCSORLEY, R., AND LIBURD, O. E. 2008.
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fornicus (acari: phytoseiidae) on arthropod commu-
nity structure in north Florida strawberry fields.
Florida Entomol. 98: 436-445.
FUNDERBURK, J., STAVISKY, J., AND OLSON, S. 2000.
Predation of Frankliniella occidentalis (Thysan-


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29: 376-382.
JACOBSON, R. J. 1997. Integrated pest management
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KIMAN, Z. B., AND YEARGAN, K. V. 1985. Development
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LIBURD, O. E., AREVALO, H. A., MCAUSLANE, H. J., AND
KREWER, G. 2006. Thrips and gall midge control.
Proceedings for the Georgia Blueberry Conference,
Georgia-South Carolina Muscadine Conference,
North American Bramble Growers Association Con-
ference 135-138.
MOSSLER, M. A., AND NESHEIM, O. N. 2007. Strawberry
pest management strategic plan (PMSP). Food Sci-
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Agricultural Sciences, University of Florida. EDIS
CIR1443: 17. Gainesville, FL.
MOUND, L. A., AND TEULON, D. A. J. 1995. Thysan-
optera as phytophagous opportunists, pp. 2-19 In B.
L. Parker, M. Skinner, T. and Lewis, T. [eds.], Thrips
Biology and Management. Plenum. New York, NY.
PARRELLA, M. P., AND LEWIS, T. 1997. Integrated pest
management (IPM) in field crops, pp. 595-614 In T
Lewis [ed.], Thrips as Crop Pests, CAB Internation-
al. Wallingford, UK.
PRICE, J. F., CHANDLER, C. K., DUVAL, J. R., RONDON, S.
I., AND CANTLIFFE, D. J. 2006. Thirty years of ad-
vances in arthropod management in Florida's com-
mercial strawberries. Acta Hort. 708: 151-154.
RONDON, S. I., PRICE, J. F., AND CANTLIFFE, D. J. 2005.
Strawberries: Main Pests and Beneficials in Florida.
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sidiosus (Hemiptera: Anthocoridae) for control of
Frankliniella occidentalis (Thysanoptera: Thripi-
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VAN DE VEIRE, M., AND DEGHEELE, D. 1995. Compara-
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native food always enhance biological control? The
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Florida Entomologist 92(1)


March 2009


EDUCATION AND TRAINING TO INCREASE ADOPTION OF IPM FOR
WESTERN FLOWER THRIPS, FRANKLINIELLA OCCIDENTALIS
(THYSANOPTERA: THRIPIDAE)


JENNIFER L. GILLETT-KAUFMAN1, NORMAN C. LEPPLA1, AMANDA C. HODGES2 AND JOYCE L. MERRITT1
1Entomology and Nematology Department, University of Florida, IFAS, IPM Florida, Gainesville, FL 32611
E-mail: gillett@ufl.edu, ncleppla@ufl.edu, joycem@ufl.edu

2Entomology and Nematology Department, University of Florida, IFAS,
Southern Plant Diagnostic Network, Gainesville, FL 32611
E-mail: achodges@ufl.edu

ABSTRACT

The University of Florida, IFAS, IPM Florida and Southern Plant Diagnostic Network
(SPDN) are cooperatively developing education and training to increase integrated pest
management (IPM) of western flower thrips (WFT), Frankliniella occidentalis (Pergande).
Management of WFT is exacerbated by difficulty in identifying thrips species and by their
development of insecticide resistance. Education and training will emphasize workshops on
identification of thrips; insecticide resistance management protocols; description of the ef-
fects of insecticides on natural enemies, i.e., Orius spp., and use of the "Grower's IPM Guide
for Florida Tomato and Pepper Production". Thrips identification aids, such as a national
field-based identification deck currently under development by the SPDN and the North
Central IPM Center (NCIPMC), will be useful to Florida growers. This kind of information
will be delivered through Extension programs, including workshops, in-service training,
field days, and classroom education. A section of the IPM Florida website is devoted to thrips
in several Florida crops (blueberry, cotton, greenhouse and nursery grown ornamentals, pep-
per, strawberry, tomato) and contains general information, such as (1) F occidentalis biology
and ecology, (2) management tactics incorporated into an IPM program that is crop and lo-
cation specific, (3) identification of thrips and natural enemies, (4) practices that reduce
damaging pest populations in space and time, (5) problems with managing F. occidentalis
and other pests, (6) updated, crop and location specific information on population levels, and
(7) resistance monitoring. Future needs for specific in-service or other educational programs,
including advanced diagnostic training sessions, will be determined by clientele groups.
Adoption of IPM for WFT will benefit growers by minimizing insecticide resistance and max-
imizing benefits of cultural practices and biological controls.

Key Words: western flower thrips, IPM, education, training, identification, extension.

RESUME

La Universidad de Florida, el program de MIP de IFAS en Florida y la Red de Diagnostico
de Plantas del Sur de los EEUU (SPDN) estan desarrollando cooperativamente un pro-
grama de educaci6n y entrenamiento para aumentar el manejo integrado de plagas (MIP)
sobre el trips occidental de flores (WFT), Frankliniella occidentalis (Pergande). El manejo de
WFT es agravado por la dificultad en identificar species de trips y por su desarrollo de re-
sistencia hacia los insecticides. La educaci6n y entrenamiento enfatizara talleres sobre la
identificaci6n de trips; protocolos de manejo de resistencia de insecticides; descripci6n de los
efectos de los insecticides sobre los enemigos naturales, i.e., Orius spp., y el uso de la "Guia
de MIP de los Productores para la Producci6n de Tomate y Chile". Las ayudas para la iden-
tificaci6n de los trips, como la baraca de cartas basada en la identificaci6n de trips en el
campo al nivel national que el SPDN y el Centro de MIP de Norte central de los EEUU (NCI-
PMC) estan desarrollandose actualmente, seran muy tiles para los productores en la Flo-
rida. Esta clase de informaci6n sera entregada por medio de programs de Extensi6n,
incluyendo talleres, entremiento en servicio, dias de campo y educaci6n de aula. Una secci6n
de la pagina web de MIP de Florida es dedicado a trips en various cultivos en la Florida (aran-
dano, algod6n, ornamentales en los invernaderos y viveros, chile, fresa, tomate) y contiene
informaci6n general, como (1) la biologia y ecologia de F. occidentalis, (2) tacticas de manejo
incorporadas en programs de MIP que son especificas al cultivo y la localidad, (3) identifi-
caci6n de trips y enemigo naturales, (4) practices para reducir las poblaciones daninas de la
plaga en espacio y tiempo, (5) problems en el manejo de F occidentalis y otras plagas, (6)
informaci6n especifica y actualizada sobre el nivel de la poblaci6n en diferentes cultivos y lo-
calidades, y el monitoreo de resistencia. Las necesidades en el future para programs en ser-
vio especificos y otros programs educativos, incluyendo sesiones avanzadas de entremiento







Gillett-Kaufman et al.: Extension to Increase IPM for WFT


de diagnostic, sera determinadas por los grupos de clients. La adopci6n de MIP para WFT
beneficiary a los productores en minimizar la resistencia hacia los insecticides y maximizar
los beneficios de practices culturales y de control biol6gico.


The development of sustainable approaches for
managing western flower thrips (WFT), Franklin-
iella occidentalis (Pergande) (Thysanoptera:
Thripidae), and the tospoviruses they vector, re-
quires accurate species identification and under-
standing of the behavior and ecology of thrips
(Funderburk 2002). WFT is the most efficient vec-
tor of tomato spotted wilt virus (TSWV). Although
WFT is a common species in Florida and the U.S.,
specimens can be confused with other species in
the field, partly due to the wide variation of color
morphs. As Florida and the U.S. are constantly at
risk from the potential introduction of non-indig-
enous species and limited taxonomic information
is available for thrips, correct identification is a
key component of any integrated pest manage-
ment (IPM) program.
Knowledge of the geographic distribution and
movement of thrips can be used to prevent out-
breaks and minimize damage to crops. Due to
trade and travel routes, storm patterns, and cli-
mate, Florida is highly suitable to establishment
of exotic thrips. Many of the non-indigenous
thrips detected in Florida within the last 20 years
have become important pest species (Edwards
1995; Edwards 1996; Edwards 2000; Hamon &
Edwards 1994). Of the 275 known species of
thrips from Florida, 55 are not believed to be in-
digenous to North America (Diffie et al. 2008). Ad-
ditionally, 10 non-indigenous species have been
reported in Georgia but have not yet been de-
tected in Florida. Unfortunately, the number of
species occurring in Florida and North America is
not completely known or described in the litera-
ture due to limited faunistic studies (Diffie et al.
2008).
A multi-tactic IPM program for thrips man-
agement is especially critical due to the potential
development of insecticide resistant thrips popu-
lations. Resistance of WFT to pyrethroids in Flor-
ida has been reported by Leibee & Capinera
(1995). As a consequence, information on resis-
tance management has been included in our edu-
cation and training programs. Insecticides for
thrips control and the exclusive use of resistant
crop varieties for management of plant patho-
genic viruses do not have long-term sustainability
(Funderburk 2002). These single tactic ap-
proaches, as well as other non-chemical manage-
ment alternatives, can be useful components in
an IPM program that incorporates a knowledge-
base of thrips behavioral and ecological informa-
tion for sustainable crop production (Momol et al.
2002).
Funderburk et al. (2000) described non-chemi-
cal management alternatives and documented


the ability of the minute pirate bug, Orius insid-
iosus (Say), to suppress WFT under natural con-
ditions of rapid colonization and population
growth. These findings indicate that natural ene-
mies play a more important role in regulating
thrips populations than initially suspected.
Funderburk (2002) reported that expansion of
thrips populations can be suppressed by natural
enemies other than the minute pirate bug. Adop-
tion of IPM for WFT will benefit the growers by
minimizing insecticide resistance and maximiz-
ing the use of cultural practices and biological
controls. Thus, conservation of all natural ene-
mies is an important aspect of this education and
training program.
Several methods of information delivery have
been developed or planned to educate Florida ag-
ricultural producers about available IPM strate-
gies. Mayfield et al. (2003) stated that future
thrips extension efforts in Florida should focus on
educating clientele about various IPM tech-
niques, including selection of appropriate culti-
vars, use of reflective mulch, and conservation of
natural enemies. Several factors influence crop
protection decisions in Florida. An education and
training framework is being provided to assist
Florida growers in determining the impact on
overall crop health of the many aspects of produc-
tion. Additionally, with training, the University of
Florida, Institute of Food and Agricultural Sci-
ences (UF/IFAS), Distance Diagnostic and Identi-
fication System (DDIS) can be used by extension
specialists and clientele groups to communicate
pest information more rapidly via remote diag-
nostic technology.
Delivery of IPM information based on a foun-
dation of thrips identification can be accom-
plished with several different venues to encom-
pass the wide variety of clientele needs in Florida.
Extension programs occur through in-service
training workshops for extension faculty and sev-
eral activities open to agricultural producers in-
cluding workshops, field days, formal and infor-
mal classroom education, and advanced diagnos-
tic training. Extension education for agricultural
producers is the primary goal of this program and
intensive diagnostic training for land grant uni-
versity extension specialists, county educators,
and researchers is a secondary objective.
Using predominantly UF/IFAS published ma-
terial, we have collected the most up-to-date con-
tent for these educational programs. Some con-
tent for current and future traditional workshops
with face to face training, includes information on
the following: (1) life history and virus vector po-
tential, (2) signs and symptoms of damage, (3)







Florida Entomologist 92(1)


sampling techniques, (4) field identification of
thrips with a hand lens, (5) thrips slide-mounting
techniques, (6) dissecting and/or compound mi-
croscope identification of thrips, (7) use of a dis-
secting and/or compound microscope with a cam-
era attachment for digital sample submission,
and (8) developing a thrips IPM plan. Specific con-
tent for individual workshops is adapted to the
needs of different clientele groups.
Training sessions based on the outline above
would usually include both laboratory and field-
based hands-on components; educational mate-
rial delivered would include 5 to 8 separate train-
ing exercises or sessions. The first session would
typically cover life history and virus vector poten-
tial, including information on TSWV and impa-
tiens necrotic spot virus because their vectors in-
clude WFT, Florida flower thrips (F bispinosa),
and tobacco thrips (F fusca). Because symptoms
vary depending on host species, cultivar, develop-
mental stage, and environmental conditions,
workshop participants are urged to base control
recommendations on insects collected, not dam-
age recorded. Signs and symptoms of suspect
thrips damage are covered as the second topic
during many training sessions, but it is empha-
sized that damage alone is not indicative of thrips
feeding if the insects cannot be found. Scouting
and sampling technique recommendations are
covered in the fourth session of most workshops.
Details on collection include either use of an aspi-
rator or a white paint board. Field identification
of WFT can be difficult due the small size of adults
(~less than 1 mm) (Jensen 2000). Although field
viewing of thrips is often inadequate to identify
them at the species level, this topic is often cov-
ered during training. The identification compo-
nent of training workshops in some instances fo-
cuses on common species that may be confused
with WFT, as well as species currently not occur-
ring in Florida.
Land grant university extension specialists as
well as state and federal (USDA, APHIS, PPQ)
identifiers are the primary target audience for ad-
vanced thrips training. These advanced diagnos-
tic training sessions familiarize students with
slide-mounting procedures for confirmatory diag-
nosis, more details in terms of thrips morphology,
and the use of dichotomous and LUCID keys
(Moritz et al. 2004) for identification. Advanced
diagnostic training often includes information re-
garding rapid screening for thrips species via a
stereoscope, but the use of more detailed keys to
identify thrips species is a major emphasis. Ad-
vanced diagnostic training requires hands-on in-
teractions with instructors and cannot currently
be conducted effectively through distance educa-
tion.
Training increases the comfort level of the stu-
dents with thrips identification, but confirma-
tions may still be requested for identified speci-


mens. Because of this, training on the use of a dis-
secting and/or compound microscope with a cam-
era attachment often is included to prepare
students for digital sample submission. The UF/
IFAS Distance Diagnostic and Identification Sys-
tem (DDIS) is an excellent point source of identi-
fication communication. This online sample sub-
mission system (http://ddis.ifas.ufl.edu/ddisx/
home.jsp) allows the user to receive assistance
with identification. In training sessions, partici-
pants are taught how to take photographs of sam-
ples, login to DDIS, and upload images to the
DDIS website. Specialists in thrips identification
are notified by DDIS of the submitted sample.
Specialists login to the DDIS system, and the sub-
mitter is notified once a sample has been re-
viewed. The time interval for the confirmation of
identification may be within hours or days, de-
pending upon specialist availability and image
quality. In some cases, a physical sample will be
requested by the specialists if the identification
cannot be confirmed from the photo. Due to this
occasional request, training is provided on preser-
vation techniques for thrips specimens.
Hands-on training is not always convenient for
clientele, so capability has been developed to de-
liver information electronically. The website on
thrips in Florida crops includes information on
several cropping systems impacted by WFT, in-
cluding blueberry, cotton, greenhouse and nurs-
ery grown ornamentals, pepper, strawberry, and
tomato. The site, called the Thrips Pest Manage-
ment site, is located online at (http://
ipm.ifas.ufl.edu/agriculture/vegetables/thrips/in-
dex.shtml). Plans for the Thrips Pest Manage-
ment site of the IPM Florida website include the
addition of new material that has been delivered
in the hands-on training sessions. Thrips 101 is
the first section on the Thrips Pest Management
site, and it offers general information on the life
cycle and habits of thrips species. Web-users also
have links available to the Thrips Specialists
Working Group (TSWG), a collection of Florida
based thrips specialists who can help answer
questions or assist with identification and man-
agement recommendations (Table 1). The site also
lists the hands-on education and training activi-
ties available in Florida. These lists are updated
often and usually include two or three upcoming
training opportunities.
The Thrips Pest Management site has many
links to thrips management and identification re-
sources available for free. There is a direct link to
the "Grower's IPM Guide for Florida Tomato and
Pepper Production" (Gillett et al. 2006). This on-
line production guide outlines several of the IPM
techniques used to manage WFT. Additional links
are available on the Thrips Pest Management site
for quick access to information on other thrips
species that may be of interest to agricultural pro-
ducers. Material is being added as it is modified or


March 2009







Gillett-Kaufman et al.: Extension to Increase IPM for WFT


TABLE 1. THE THRIPS SPECIALISTS WORKING GROUP
(TSWG) IS A COLLECTION OF FLORIDA-BASED
SPECIALISTS WHO ARE WILLING TO ASSIST
WITH THRIPS IDENTIFICATION, MANAGEMENT
AND EDUCATIONAL PROGRAMMING. MEMBERS
OF THE TSWG ARE DIVIDED BY PRIMARY AREA
OF RESPONSIBILITY.

Number
Primary area of responsibility of specialists

Identification and Management 15
Extension 15
Industry Management 9
Education 3


developed to several sections on the Thrips Pest
Management site. These include: scouting, identi-
fication of thrips, identification of natural ene-
mies of thrips, general IPM practices that reduce
thrips populations, thrips management in specific
crops, challenges of thrips management, and
tracking thrips resistance to insecticides. Most of
the information being modified for these sections
is currently available in the "Grower's IPM Guide
for Florida Tomato and Pepper Production" and in
UF/IFAS Electronic Data Information Source
(EDIS) documents. Our goal is to make quick
links to the most up-to-date information available
to encourage its use by agricultural producers.
The educational goal of this program is to
teach extension faculty members and agricultural
producers how to design crop-specific IPM sys-
tems based on correct identification and multi-
tactic management of WFT The effort will build
on four highly successful thrips identification and
training courses that have been conducted in re-
cent years, including chilli thrips Polycom train-
ing (Dec 2005), thrips identification and sampling
training (Mar 2006), a Florida landscape and or-
namental thrips workshop (Aug 2007), and a
Polycom meeting of statewide thrips specialists
(Jun 2008). At least 85 participants attended
these thrips-related courses in Florida. Thrips
identification, management, and regulatory ex-
pertise was provided by Joe Funderburk (UF/
IFAS, North Florida Research and Education
Center (REC)), Lance Osborne (UF/IFAS, Mid-
Florida REC), Dak Seal (UF/IFAS Tropical REC),
G.B. Edwards (Florida Department of Agriculture
and Consumer Services, Division of Plant Indus-
try), Stuart Reitz (USDA, Agricultural Research
Service), Richard Clark (retired, formerly
FDACS, DPI), and Scott Ludwig (Texas A&M
AgriLife Extension). The chilli thrips Polycom
training was designed specifically to provide
rapid information about chilli thrips as a new pest
to Florida. At the request of county Extension fac-
ulty, Joe Funderburk also conducted several in-
formal thrips identification sessions during the
last few years.


Additional training sessions conducted by the
Southern Plant Diagnostic Network (SPDN) in-
cluded an invasive arthropod meeting (May 2007) in
Clemson, South Carolina that offered an optional
advanced training session for thrips identification.
Instructors for the course included Joe Funderburk
and Stan Diffie (University of Georgia). The supple-
mental training at Clemson, along with the previ-
ous 3-day thrips workshop in Gainesville, Florida
(Mar 2006), were the only 2 sessions that provided
advanced diagnostics training for participants from
Florida. Approximately 20 participants attended
each session. For the advanced taxonomic training
in Gainesville, Florida, most of the attendees repre-
sented laboratory staff, statewide extension special-
ists or researchers with UF or USDA, ARS. Some
participation from Florida statewide extension spe-
cialists occurred at the 2007 SPDN regional train-
ing, but most of the audience included extension di-
agnosticians from other states or USDA, APHIS,
PPQ identifiers.
The advanced diagnostic training for thrips,
and other arthropods, continues to be a priority
activity for entomologists in the National Plant
Diagnostic Network (NPDN). Following advanced
diagnostic training, participants are more capa-
ble to use keys for initial species-level identifica-
tions. Workshop participants often are in commu-
nication with instructors post-conference, for both
initial identifications and final confirmations.
Surveys were distributed to determine the effec-
tiveness of this training and the responses were
extremely favorable for 3 aspects of the training:
instructors, learning environment, and workshop
design. Many participants requested brief video-
conference updates for new pest information.
Agricultural producers have special needs for
education and training on thrips IPM. To meet
these needs, educational materials have been or
are being developed, including thrips identification
aids, i.e., I.D. deck, and insecticide resistance man-
agement protocols. Product rotation is an impor-
tant aspect of WFT management because this pest
is resistant to almost all insecticides (Jensen
2000). Moreover, IPM can be difficult with multiple
pests in a crop. For example, chemical control of
pepper weevil, Anthonomus eugenii, and sweetpo-
tato whitefly, Bemisia tabaci, can disrupt the natu-
ral enemy complex that naturally manages WFT
(Funderburk et al. 2000; Gillett et al. 2006). Use of
the "Grower's IPM Guide for Florida Tomato and
Pepper Production" and other online resources,
such as the Thrips Pest Management site, can help
producers create a comprehensive crop manage-
ment plan to maintain high populations of natural
enemies and minimize pest problems. The Thrips
Pest Management site was developed in the sum-
mer of 2008 and has already become a well-used
resource. Web statistics collected from Jul to Nov
20, 2008 show the number of "hits" for these thrips
specific resources (Table 2).







Florida Entomologist 92(1)


TABLE 2. NUMBER OF "HITS" FOR THE THRIPS PEST MAN-
AGEMENT SITE ON THE IPM FLORIDA WEBSITE
(JUL 1 TO NOV 20, 2008).

Number
Sources of thrips educational information of hits

Entire Thrips Website 5,016
Thrips Pest Management Home Page 1,192
Thrips Education and Training Activities 259
Thrips Specialists 206
Thrips Management in Specific Crops 221
Insecticides 209
News Releases 177
Links 173
Thrips Identification 192
Biology of Thrips 112
General IPM Practices 143
Scouting 143
Natural Enemies 138
Western Flower Thrips 8-29-08 Workshop 118



The "Grower's IPM Guide for Florida Tomato
and Pepper Production" is based on IPM princi-
ples that emphasize pest prevention, rather than
reaction, and up front planning to reduce the
risks and costs of pest management. It presents
options for tomato and pepper production in Flor-
ida, including management of soil nutrients,
pests, diseases and weeds, as well as cultural,
physical, biological, and chemical controls. The
guide outlines several of the IPM techniques used
to manage WFT and contains specific information
about 4 thrips species in Florida and their man-
agement: Florida flower thrips, F bispinosa; to-
bacco thrips, F fusca; melon thrips, Thrips palmi;
and WFT. Web statistics collected in the first 11
months of 2008 indicate the usefulness of this ed-
ucational guide (Table 3). These statistics do not
take into account the number of times the refer-
ence has been used offline, since 750 copies were
distributed on CD and 60 as hard bound copies to
key growers, scouts, and faculty members.

DISCUSSION

Demand will increase for WFT IPM training
and associated materials as this pest spreads to
new agricultural production areas in Florida.
Consequently, plans are underway for more work-
shops on WFT identification and management. A
"Thrips Identification Deck" is being developed by
the SPDN and North Central IPM Center to as-
sist scouts and growers who are learning how to
distinguish between thrips species. Assistance
will be provided by members of the TSWG to de-
velop and implement crop and location specific in-
secticide resistance management programs. As a
follow-up to these extension efforts, post training
surveys of educational needs will be conducted.


TABLE 3. NUMBER OF "HITS" FOR THRIPS IPM EDUCA-
TIONAL INFORMATION IN THE ONLINE RE-
SOURCE "GROWER'S IPM GUIDE FOR FLORIDA
TOMATO AND PEPPER PRODUCTION" (JAN 1 TO
Nov 20, 2008).

Number
Sources of thrips educational information of hits

Entire Guide 50,131
Chapter 4-Pest Management 2,284
Florida Flower Thrips 397
Tobacco Thrips 286
Melon Thrips 293
Western Flower Thrips 320
Chapter 8-Biological Control 452
Chapter 7-Cultural and Physical Controls 460
Mulches 240
Planting Dates and Times 174
Field Sanitation 184
Off-Season Management and Cover Crops 248
Off-Season Management and Double Cropping 162
Windbreaks 184
Chapter 9-Chemical Control 559
Biorational Insecticides 413
Pest Resistance 179
Restricted Use Pesticides 150
Appendix 8-Tospovirus 286


These surveys will assure that future efforts have
the maximum benefit for Florida's agricultural
community.

ACKNOWLEDGMENTS

We gratefully acknowledge the assistance of the fol-
lowing individuals who gave generously of their time to
make these educational training materials available:
Jerry Bartz, Eileen Buss, Lyle Buss, Carlene Chase, Matt
Ciomperlik, Richard Clark, Kent Cushman, G.B. Ed-
wards, Jason Ferrell, Fred Fishel, Howard Frank, Ronald
French-Monar, Joe Funderburk, Phyllis Gilreath, Heidi
HansPetersen, Tyler Harp, Pingsheng Ji, Jeff Jones,
Waldy Klassen, Barbra Larson, Michael Mahovic, Gene
McAvoy, Bob McGovern, Cindy McKenzie, Jane Medley,
Tim Momol, Mark Mossler, Joe Noling, Lance Osborne,
Steve Olson, Monica Ozores-Hampton, Ken Pernezny,
Jane Polston, Pam Roberts, Jim Price, David Schuster,
Dak Seal, Eric Simonne, Tom Skarlinksy, Phil Stansley,
Bill Stall, Charles Stuhl, and Denise Thomas. We thank
Denise Thomas for help collecting website information.
The UF/IFAS, IPM Florida program is funded by the
USDA, Cooperative State, Research, Education, and Ex-
tension Service (CSREES). The Southern Plant Diagnos-
tic Network is funded by USDA, CSREES Cooperative
Agreement 2007-37620-18196. Funding for production
and printing of the thrips identification deck was pro-
vided by USDA, CSREES Award No. 2007-41530-03984.
Material development for the "Grower's IPM Guide for
Florida Tomato and Pepper Production" was supported
by a grant from the USDA, CSREES Pest Management
Alternatives Program (PMAP) 2003-34381-13593, "In-
corporating Alternative, Multi-tactic IPM into the Crop
Planning Process of Florida Vegetable Growers."


March 2009







Gillett-Kaufman et al.: Extension to Increase IPM for WFT


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DIFFIE, S., EDWARDS, G. B., AND MOUND, L. A. 2008.
Thysanoptera of Southeastern U.S.A: A checklist for
Florida and Georgia. Zootaxa. 1787: 45-62.
EDWARDS, G. B. 1995. Thrips (Thysanoptera) New to
Florida: II. Thripidae: Thripinae (Psydrothrips, As-
prothrips). Fla. Dept. Agric. Consumer Serv., Div.
Plant Indus. Entomol. Circ. 371: 1-2.
EDWARDS, G. B. 1996. Thrips (Thysanoptera) New to
Florida: III. Thripidae: Thripinae (Chaetanapho-
thrips, Danothrips). Fla. Dept. Agric. Consumer
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EDWARDS, G. B. 2000. Thrips (Thysanoptera) New to
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lacothrips). Fla. Dept. Agric. Consumer Serv., Div.
Plant Indus. Entomol. Circ. 398: 1-2.
FUNDERBURK, J. E. 2002. Ecology of thrips. Thrips and
Tospoviruses, pp. 121-128 In R. Marullo and L. A.
Mound [eds.], Proc. 7th Intl. Symp. on Thysanoptera,
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FUNDERBURK, J. E., STAVISKY, J., AND OLSEN, S. 2000.
Predation of Frankliniella occidentalis (Thysan-
optera: Thripidae) in field peppers by Orius insidio-
sus (Hemiptera: Anthocoridae). Environ. Entomol.
29:376-382.
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AND THOMAS, D. D. [EDS.]. 2006. Grower's IPM
Guide for Florida Tomato and Pepper Production.


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T&PGuide/index.shtml (Last accessed September
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anoptera) New to Florida: I. Thripidae: Panchaeto-
thripinae. Fla. Dept. Agric. Consumer Serv., Div.
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Florida Entomologist 92(1)


March 2009


ASSESSMENT OF IMPLEMENTATION AND SUSTAINABILITY OF
INTEGRATED PEST MANAGEMENT PROGRAMS

ANTHONY WEISS', JAMES E. DRIPPS2 AND JOE FUNDERBURK3
'Dow AgroSciences, 804 River Hammock Blvd., Brandon, FL 33511

2Dow AgroSciences, 9330 Zionsville Rd., Indianapolis, IN 46268

3North Florida Research and Education Center, University of Florida, 155 Research Road, Quincy, FL 32351

ABSTRACT

All parties involved in growing the world's food, including growers, crop consultants, univer-
sity researchers, extension personnel, national and regional regulatory agencies, and the
agrochemical and seed industry, spend significant time, money, and effort to solve the prob-
lems associated with growing food. The needs of these parties are varied and sometimes in
conflict, which is not always conducive to developing and implementing integrated pest
management (IPM) systems that are both sustainable and economical. IPM encompasses si-
multaneous management of multiple pests, regular monitoring of pests and their natural
enemies and antagonists, use of economic or treatment thresholds when applying pesticides,
and integrated use of multiple, suppressive tactics. IPM components with the greatest im-
pact on resistance management are rotating classes of chemistry, use of recommended rates,
not exceeding label restrictions, and avoiding sequential treatments of products with the
same mode of action. The best way to insure that these components are followed is to have
pesticide record keeping and reporting. However, pesticide use record keeping and reporting
are not currently required in all areas. Other activities that can be integrated include edu-
cational workshops on IPM, resistance monitoring of pests to pesticides, proper identifica-
tion of pests and natural enemies, real time scouting reports on the pests that are being
found, maintenance of a data base on the effects of various products on natural enemies, and
field validation of IPM use.

Key Words: Frankliniella occidentalis, pepper, eggplant, tomato, strawberries, integrated
pest management, resistance management, implementation, assessment, sustainability

RESUME

Todos los grupos envueltos en la siembra de alimentos para el mundo, incluyendo los pro-
ductores, asesores de cultivos, investigadores universitarios, personal de extension, agen-
cias regulatorias nacionales y regionales y las industries de agroquimica y de semilla,
gastan tiempo, dinero y esfuerzo significativos para resolver problems asociados con la
siembra de alimentos. Las necesidades de estos grupos son diversos y a veces estan en con-
flicto, lo cual a veces no es bueno para el desarrollar e implement de sistemas de manejo in-
tegrado de plagas (MIP) que son sostenibles y econ6micos. El MIP abarca el manejo
simultaneo de plagas multiples, el monitoreo con regularidad de plagas y sus enemigos na-
turales y antagonistas, el uso de umbrales econ6micos o de tratamiento cuando aplican pes-
ticidas, y el uso integrado de tacticas supresivas multiples. Los components de MIP de
mayor impact sobre el manejo de resistencia son el alternar diferentes classes de quimicos,
el uso de la cantidad recomendada del product, no exceder las restricciones de etiqueta, y
evitar tratamientos secuenciales de products con la misma moda de acci6n. La mejor ma-
nera para asegurar que estos components son seguidos es mantener un registro de los pes-
ticidas usados y reportarlos. Sin embargo, el mantenimiento de un registro y el report de
los pesticides usados no es requerido actualmente en todas las areas. Otras actividades que
pueden ser integrados incluyen talleres educativos sobre MIP, el monitoreo de resistencia de
las plagas hacia los pesticides, la identificaci6n correct de plagas y enemigos naturales, in-
formes en tiempo real de los inventarios de cultivos sobre las plagas que se encuentran, el
mantenimiento de un base de datos sobre los efectos de various products sobre los enemigo
naturales, y la validaci6n del uso de MIP en el campo.


Many parties, including growers, crop consult- of food crops. "Pest management stakeholders"
ants, university researchers, extension personnel, spend significant time, money, and effort to solve
the federal and state regulatory agencies, and the the technical, economic, and social issues associ-
agrochemical and seed industry are involved in ated with growing food crops. The needs of stake-
managing pests that reduce the yield and quality holders are varied and sometimes in conflict.







Weiss et al.: Assessment of IPM Programs


Growers want simple, effective, and inexpensive
solutions to pest problems and they expect new
products with better attributes to replace older
products. Crop consultants need to balance the
cost or scheduling demands of the grower with
what the consultant knows is the best prescrip-
tion for the problem. University researchers want
to develop science-based and holistic IPM solu-
tions and extension personnel want to success-
fully implement these programs. The agrochemi-
cal industry strives to develop products that are
IPM-compatible, with a long effective life
(20+ years), competitive with alternative prod-
ucts, and to provide an economic return to the
company's shareholders. To meet their individual
needs, the pest management stakeholders must
look for common ground and work together to de-
velop and implement IPM systems that are sus-
tainable and economical.
To successfully develop and implement sustain-
able and economical IPM systems, the stakehold-
ers must first agree on the scope of the desired out-
comes. Ehler et al. (2006) state that for the IPM
practitioner, IPM encompasses the simultaneous
management of multiple pests, regular monitoring
of pests and their natural enemies and antago-
nists, use of economic or treatment thresholds
when applying pesticides, and integrated use of
multiple suppressive tactics. Integration of IPM
tactics may be vertical or horizontal. "Vertical"
IPM refers to the integration of multiple, compati-
ble tactics to control one group of pests (insects/ar-
thropods or pathogens or weeds). "Horizontal" IPM
refers to the integration of multiple, compatible
tactics to control more than 1 group of pests (in-
sects/arthropods, pathogens, and weeds). Although
full horizontal integration is clearly the ideal re-
sult to strive for, in practice, achieving vertical in-
tegration of IPM tactics for a single pest takes sig-
nificant effort. Pest management stakeholders
should start with realistic expectations about the
scope of their efforts to assess the implementation
and sustainability. We recommend starting at a
relatively small level of integration, namely a sin-
gle insect pest across a range of crop systems. With
the scope of IPM established, stakeholders can as-
sess the implementation and sustainability of IPM
programs.
Our analysis and discussion will relate to as-
sessing the implementation and sustainability of
IPM tactics for western flower thrips (WFT),
Frankliniella occidentalis, in Florida tomatoes,
peppers, eggplant, blueberries, and strawberries.
A number of specific IPM tactics have been devel-
oped and are recommended for managing WFT in
fruiting vegetables (Reitz et al. 2003; Momol et al.
2004; Funderburk et al. 2008). Among these tac-
tics are thrips identification, use of treatment
thresholds, use of Orius:WFT population ratios,
conservation of biological control, natural enemy
refugia, use of ultraviolet-reflective mulches, inte-


grated resistance management, use of selective
insecticides that have minimal effects on natural
enemy populations, care to not overuse pesticides
and especially those that induce WFT, and good
sanitation. Thrips identification is important be-
cause thrips species other than F occidentalis
generally do not cause economic damage. The use
of treatment thresholds and use of Orius:WFT
population ratios are important because if Orius
parasitoids are in sufficient numbers, they will
keep WFT under control. Conservation biological
control, natural enemy refugia, and the use of ul-
traviolet-reflective mulches, reduces initial WFT
immigration into a field. Integrated resistance
management includes the rotation of insecticides
from different chemical classes, thus preventing
the overuse of pesticides. The use of selective in-
secticides that have minimal effects on natural
enemy populations, is vital in the control of WFT.
The primary selective insecticide used for WFT
management is spinosad. Spinosad insecticide
products were first introduced in the late 1990s and
have been highly effective in controlling western
flower thrips and widely used for this purpose (Eger
et al. 1998). There have been isolated incidents of re-
sistance to spinosad in several insect pest species.
In these cases, resistance has been recessive and re-
ducing spinosad use to reduce selection for resis-
tance has resulted in regaining susceptibility in
most cases. Spinetoram, a new and more active in-
secticide, was registered for use in 2008.

CASE STUDY WESTERN FLOWER THRIPS
RESISTANCE, PALM BEACH FL

In 2006, a grower in Palm Beach County FL re-
ported that spinosad was not providing the ex-
pected level of WFT control in his bell pepper
fields. Spray timing, use rate, product quality, ap-
plication quality, and application equipment were
examined and eliminated as possible factors in
lack of performance. WFT were collected from the
grower's field and bioassayed by the method de-
veloped by Eger et al. (1998) to determine if sus-
ceptibility to spinosad had changed. This WFT
strain was exposed to 11 PPM and 123 PPM, the
LCg, and LC99 values established for spinosad
from baseline susceptibility testing (Eger et al.
1998). Mortality was less than 20% at each con-
centration, indicating that tolerance to spinosad
had developed in this population.
The initial perception of the grower was that
any thrips present would threaten the quality of
his high-value pepper crop. However, WFT was
not always among the thrips species present in
the field, so the grower was making many unnec-
essary insecticide applications to control non-
threatening thrips. In late 2006 and early 2007,
Glades Crop Care consulted with the grower to
identify the thrips species present and to make
recommendations on when to treat and what






Florida Entomologist 92(1)


other IPM tactics to follow. The result was accept-
able WFT management for a full crop season
avoiding the re-development of a highly resistant
population during that period (Fig. 1). During this
time, however, spinosad-resistant populations
were detected in fields belonging to other growers
in the same area.
As a mitigation effort, workshops to make
growers aware of WFT resistance were held in
Homestead and Palm Beach, FL in May 2007. The
objectives of these workshops were to explain ef-
fective IPM practices, and to emphasize the need
to implement these practices in order to maintain
effective chemical control options. Additional
meetings and visits to individual growers oc-
curred between Oct 2007 and Jan 2008 to further
educate growers and to monitor WFT population
dynamics and spinosad susceptibility levels. In
Jan 2008, a meeting was held to train consultants
and extension agents in the area to identify thrips
species. The result of all of these efforts was that
several growers in the area adopted IPM tactics to
varying degrees. On the other hand, several grow-
ers did not adopt any IPM tactics and continued
to rely primarily on chemical control. Western


flower thrips susceptibility to spinosyns was
maintained in those fields where IPM tactics were
adopted while it did not improve in those fields
where control was relied only on chemical control
(Figs. 2 and 3). This data suggests that in areas
where resistance is present, the level of WFT re-
sistance on a farm can be directly related to the
level of IPM practiced by the grower.
Integrated resistance management (IRM) pro-
grams are closely related to IPM programs but
IRM programs are focused only in the chemical
component of IPM programs. A successful IRM
program involves the following concepts: rotation
of several classes of chemistry with different
mode of action (MoA), the use of recommended
rates, the limitation of maximum number of ap-
plications and product per acre per year or sea-
son, and to avoid sequential treatments within a
single planting and across sequential crops/plant-
ings.
Mandatory pesticide use record keeping and
reporting is needed to determine the level of adop-
tion of IPM and IRM programs by growers. These
records should include the products used, the
rates applied, the frequency and timing of appli-


. LC90 conc

. LC99 conc


05-May-06 JanO7N Mar07S 06-Mar-07 21-Mar-07
End of No Spinosad Spinosad WFT Managed based
2006 crop Sprayed to sprayed on thresholds
season This Date twice


Fig. 1. Bioassays of Spinosad toxicity of adult western flower thrips collected from a farm in Palm Beach Co.,
Florida.


100-

90-

80-

70-

60-

50-

40-

30-

20-

10-

0-


March 2009







Weiss et al.: Assessment of IPM Programs


100- Spinetoram spray tank
90- conc. = 44-150 pgI/mL
80-

70-
60-
50-oil
X 8 pglml
= 40- X "
E 30-
20-

0-


IPM Non-IPM
Grower Grower
Fig. 2. Effect of IPM vs no IPM. Bioassay of Spinetoram toxicity to WFT collected from a pepper farm where the
grower employed IPM and another pepper farm where the grower relied on calendar sprays of insecticides, Palm
Beach Co., Florida.


cations, and the sequences of pesticide treat-
ments. State-wide pesticide record keeping and
reporting is currently not a legal mandate in Flor-
ida.
So, what else can be done to measure IPM im-
plementation? We must first start with education
efforts with the objectives to scout, identify thrips
species, and to implement IPM tactics. State wide
educational efforts are targeted at extension
agents, consultants, industry, growers, and oth-
ers. Measurement on the success of this would be
in the form of Continuing Education Units (CEU)
or Certified Crop Advisor (CCA) credits at each
session. Tracking of attendance and results of a
pre and post workshop test also should be
tracked. This will encourage participants to learn
and retain the information about the various IPM
tactics. The trainers should compare pre- and
post-test scores to measure the effectiveness of
training.
An indirect way to assess the effectiveness of
these workshops will be to monitor for resistance
with the objective to have each company work
with university researchers to set up monitoring
procedures and to evaluate the extent of resis-
tance development. University researchers would
be in charge of maintaining the data base to as-
sess progress.
University extension specialists need to de-
velop specific management recommendations for


fruiting vegetables, strawberries, and blueberries
that are vertically integrated and that are specific
to different locations. This will help educate on
the tactics and tools needed to practice IPM and
IRM effectively. Use of the National Distance Di-
agnostic & Identification System (DDIS) will fa-
cilitate the proper identification of thrips.
Real-time scouting information available on a
website that is crop and location specific will be an
important component to continuously connect with
consultants, extension agents, growers, and indus-
try. The reports will include county location, the
proportion of each thrips species in field, the effects
of management tactics, and the susceptibility of
western flower thrips populations to insecticides.
This information will allow everyone to know in
real time when population shifts are occurring to
enable effective changes in tactics to be utilized.
Another important component of this program
will be development of a database for the effects of
pesticides on natural enemies. The University of
Florida will create a database that would include
all pesticides (fungicides, herbicides, and insecti-
cides) to determine the effects of these pesticides
on beneficial insects. To develop the database the
University of Florida will start evaluating the ef-
fect of chemicals commonly used in these crop sys-
tems on natural enemies of thrips.
Field validation of IPM implementation is a
must. County extension will be responsible for as-







Florida Entomologist 92(1)


IPM
Grower


Non-IPM
Growers


Fig. 3. Effect of IPM vs no IPM. Bioassay of spinetoram toxicity to WFT collected on strawberries.


sessing IPM implementation of individual grow-
ers and for educating individual growers in the
principles and practice of IPM.
To make the whole process user friendly, an in-
teractive website containing educational materi-
als, current recommendations, and real-time pop-
ulation information is needed. The University of
Florida has taken on the project and will continue
to manage this system.

CONCLUSION

Enforceable reporting of pesticide use would
provide a clear measure of IPM and IRM use by
showing long-term trends in the use of chemical
control measures. Chemical control tends to be
over-used where IPM is not being practiced. Thus,
a reduction in pesticide use while maintaining
crop yield and quality should be expected to occur
when IPM is being practiced. Additional ways to
assess implementation and sustainability of IPM
programs involve measuring the use and effec-
tiveness of specific program components. The in-
clusion of tools that record attendance and profi-
ciency at educational sessions, requests for IPM
education documents, use of systems such as the
University of Florida's Distance Diagnostic Iden-
tification System (DDIS), measuring use of com-
puter-accessible real-time pest scouting reports,
the use of a database for pesticide effects on nat-
ural enemies, and surveys to validate IPM use in
the field will serve as a way to document progress.


An indirect way to measurement sustainable IPM
implementation will come from resistance moni-
toring and evaluation of resistance development.
In the example of western flower thrips manage-
ment in Florida previously described, the level of
insecticide resistance was a very clear indicator of
the adoption and use of IPM and IRM programs.
ACKNOWLEDGMENTS
We thank Charles Mellinger, Glades Crop Care, for
help, and M. Srivistava for bioassays.
REFERENCES CITED
EHLER, L. E. 2006. Perspective integrated pest manage-
ment (IPM): definition, historical development and im-
plementation, and the other IPM. Pest Man. Sci.
62:787-789.
REITZ, S. R., YEARBY, E. L., FUNDERBURK, J. E.,
STAVISKY, J., MOMOL, M. T., AND OLSON, S. M. 2003.
Integrated management tactics for Frankliniella
thrips (Thysanoptera: Thripidae) in field-grown pep-
per. J. Econ. Entomol. 96: 1201-1214.
EGER, JR., J. E., STAVISKY, J., AND FUNDERBURK, J. E.
1998. Comparative toxicity of spinosad to Franklin-
iella spp. (Thysanoptera: Thripidae), with notes on a
bioassay technique. Florida Entomol 81: 542-551.
FUNDERBURK, J. E., STAVISKY, J., AND OLSON, S. 2000.
Predation ofFrankliniella occidentalis (Thysanoptera:
Thripidae) in field peppers by Orius isidiosus (Hemi-
ptera: Anthocoridae). Environ. Entomol. 29: 376-382.
MOMOL, M. T., S. M. OLSON, J. E. FUNDERBURK, AND
J. STAVISKY. 2004. Integrated Management of toma-
to spotted wilt on field-grown tomatoes. Plant
Dis.88: 882-890.


100

90

80

70

60

50

40

30
20

10
0


March 2009


ISpinetorarn spray tank
-Loo:-- 44-1 50 Cgg/mL









1.6 pg/ml III I~







Frantz & Mellinger: Western Flower Thrips Abundance and Damage



SHIFTS IN WESTERN FLOWER THRIPS,
FRANKLINIELLA OCCIDENTALIS (THYSANOPTERA: THRIPIDAE),
POPULATION ABUNDANCE AND CROP DAMAGE

GALEN FRANTZ AND H. C. MELLINGER
Glades Crop Care, Inc., 949 Turner Quay. Jupiter, FL 33458

ABSTRACT

Since the first report of Florida establishment in 1982, the western flower thrips (WFT),
Frankliniella occidentalis (Pergande), has caused economic damage to vegetable crops, no-
tably peppers, Capsicum annuum L. A survey of thrips infesting peppers in Palm Beach
County, FL in 2006-07 showed that WFT populations were more prevalent than in a survey
conducted in 1995-96, and exceeded economic thresholds for much of the growing season.
The possible contribution of pyrethroid insecticide use to damaging populations of WFT is
discussed.

Key Words: Frankliniella occidentalis, Frankliniella bispinosa, pepper, pyrethroid, Orius in-
sidiosus

RESUME

Desde el primer informed de su establecimiento en la Florida en 1982, el trips occidental de
flores (WFT), Frankliniella occidentalis (Pergande), ha causado daio econ6mico a los culti-
vos de hortalizas, notablemente en chile, Capsicum annuum L. Un reconocimiento de los
trips que infestan chile en el Condado de Palm Beach en la Florida durante 2006-07 mostr6
que las poblaciones de WFT fueron mis prevalentes que en el reconocimiento realizado en
1995-96, y fue en exceso del umbral econ6mico por much de la temporada de crecimiento del
cultivo. Se comenta sobre la possible contribuci6n del uso de insecticides piretroides hacia po-
blaciones daninas de WFT.


The western flower thrips (WFT), Franklin-
iella occidentalis, became established in Florida
in 1982 (Kirk & Terry 2003) and quickly adapted
to local farming environments. By 1985, signifi-
cant damage and economic losses had occurred in
vegetable crops. The largest economic loss to this
pest resulted from the transmission of Tomato
Spotted Wilt Virus (TSWV) in tomato crops in
north Florida and south Georgia. Additional dam-
age resulted from WFT oviposition and feeding
(Frantz & Mellinger 1990; Funderburk & Sal-
guero 1989; McRitchie 1986).
WFT numbers have exploded in Palm Beach
County, FL (PBC), resulting in severe feeding
damage to peppers and less so in tomatoes. The
rapid change in WFT abundance in Palm Beach
County has been attributed to resistance develop-
ment to spinosad (Spintor, Dow AgroScience),
with the population increase exacerbated by fre-
quent applications of pyrethroid insecticides
(GCC, unpublished data). The development of
high WFT populations is noteworthy because the
Florida flower thrips (FFT), Frankliniella bispi-
nosa (Morgan), historically the prevalent species,
has not caused significant feeding damage to the
pepper and tomato crops in PBC. In this paper we
discuss the scope and dynamics of the WFT popu-
lation shift in Palm Beach County and factors
that contributed to the change.


MATERIALS AND METHODS

Thrips populations were monitored in surveys
during the 1995-96 and 2006-07 pepper growing
seasons at 3 different sites in Palm Beach County,
Boynton Beach (1995-96), Delray Beach (2006-07)
and Jupiter (both seasons). The Delray and Boyn-
ton Beach sites are separated by approximately 8
km, and are located about 48 km south of Jupiter.
Populations of thrips and a major predator, the
minute pirate bug (MPB), Orius insidiosus (Say),
were monitored by collecting samples of 15-25
pepper blooms into self-sealing plastic bags. The
number of samples collected during a sample in-
terval ranged from 1 (Boynton Beach) to 10 (Del-
ray Beach). Two samples per interval were col-
lected during both surveys in Jupiter. Sampled in-
sects were killed with 70% isopropyl alcohol.
Thrips were separated from blooms by agitating
the sample with water and pouring the contents
through a coarse screen to remove flower parts,
followed by a fine (120-mesh) filter. The filtrate
was transferred to Syracuse dishes for examina-
tion under 20-40 X magnification to count and
separate adult thrips by species. Larval thrips
were counted, but not identified to species. All
samples collected within approximate weekly in-
tervals were pooled and are reported as thrips per
bloom.







Florida Entomologist 92(1)


To explore causes of the explosive WFT popula-
tion increases observed in the PBC survey of
2006-07, a trial was conducted in Fort Pierce, FL,
with candidate insecticides. Subsamples of thrips
infesting pepper blooms were collected from plots
treated with methoxyfenozide (Intrepid, Dow
AgroScience), an insect growth regulator, per-
methrin (Pounce, FMC Corporation) and gamma-
cyhalothrin (Proaxis, Loveland Products, Inc.),
alone and in combination (Table 1). Test materials
were applied at labeled rates on 05/08, 05/14 and
05/21/2007. The total number of MPB and thrips
including adults and larvae, collected on each
sampling date in each treated area was deter-
mined by the survey methods described above.

RESULTS

The results of the 1995-96 survey in Boynton
Beach are shown in Fig. 1. FFT made up over 99%
of the population with a fall and spring popula-
tion peak of 5 thrips per bloom. During this pe-
riod, no crop damage was detected. Fig. 2 shows
the results of the 2006-07 survey in Delray Beach.
Following an early season peak of 7 thrips/bloom
during Nov, FFT declined to 0-0.3 thrips/bloom,
and did not rebound until Apr, 4 months later. The
WFT population was low from Sep through Dec,
but increased rapidly as FFT declined, and con-
tinued to rise, reaching a peak of over 50 thrips/
bloom in Mar. A rapid decline followed and contin-
ued through the end of the crop. The ratio of
thrips to MPB for each sampling date is shown in
Fig. 3 (the MPB numbers have been multiplied by
100 for improved readability). MPB were present
in fall and spring samples, but were absent from
winter samples.
During both seasons in Jupiter, FFT were most
numerous, although WFT were detected at the
low level of 0.2 thrips/bloom in 1996. FFT popula-
tions peaked at 17 thrips/bloom in 1996 and in
2007 peaked at 34 and 46 thrips/bloom (Figs. 4
and 5).
Insecticides applied to peppers affected thrips
populations, resulting in average numbers over
the 3-week sampling period between approxi-
mately 200 thrips per sample in the untreated


check and 600 in the gamma-cyhalothrin treated
plots (Fig. 6). Total thrips populations in plots
treated with permethrin were intermediate be-
tween these extremes (~350 per sample). Methox-
yfenozide applications did not significantly affect
numbers of thrips or MPB. Average numbers of
MPB per sample ranged from approximately 1
per sample in gamma-cyhalothrin treatments to
4.6 in the permethrin treatments to approxi-
mately 7 in the untreated plot. Methoxyfenozide
did not significantly affect MPB numbers.

DISCUSSION

The results show that WFT was virtually ab-
sent from Boynton Beach pepper crops in 1995-
96. Eleven years later, in the intensively farmed
area around Delray Beach, the WFT population
increased rapidly following the Dec-Jan decline in
FFT. Growers were surveyed and reported thrips
feeding damage to pepper pods and tomato fruits
from Jan 2007 through May, the end of the grow-
ing season (GCC, unpublished data). WFT popu-
lations during this entire period exceeded the eco-
nomic threshold of 2-3 thrips per bloom, recom-
mended by the University of Florida, Institute of
Food and Agricultural Sciences (Gillett et al.
2006). By comparison, FFT populations exceeded
this level on only 1 sample date in Oct, and no
thrips feeding damage to pods was reported by
the growers.
Several important differences exist between
Jupiter and the 2 southern survey sites. While the
southern sites are intensively farmed by numer-
ous large vegetable-growing interests, the Jupiter
site is the only vegetable farm in the vicinity and
is immediately adjacent to several large citrus
groves. Dispersal of large numbers of FFT from
citrus during the late winter blooming period is a
common event, which is reflected in both surveys
from the Jupiter site.
The Dec 2006 FFT decline in Delray Beach oc-
curred when MPB numbers were adequate to con-
trol the thrips population through predation dur-
ing the Oct-Dec period. Gillett et al. (2006) indi-
cates biological control occurs when there is at
least 1 predator per 180 prey. MPB undergo a


TABLE 1. AVERAGE NUMBER OF THRIPS, INCLUDING ADULTS AND LARVAE OF ALL SPECIES, AND MINUTE PIRATE BUGS
(MPB) COLLECTED FROM PEPPERS IN FORT PIERCE, FL DURING MAY 2007.

TOTAL THRIPS/SAMPLE MPB/SAMPLE
TREATMENT (ALL DATES (ALL DATES)

UTC 202.3 7.1
Methoxyfenozide 206.4 7.3
Permethrin 342.7 4.6
Permethrin + Methoxyfenozide 362.4 4.6
Gamma-cyhalothrin 600.1 1.1
Gamma-cyhalothrin + Methoxyfenozide 536.4 1.6


March 2009








Frantz & Mellinger: Western Flower Thrips Abundance and Damage


Fig. 1. Number of adult and larval thrips collected from pepper blooms, Boynton Beach, FL 1995-96.





30


---- Frankliniella bispinosa
25 ----- Frankliniella occidentalis


0 i 0 0 0 0 0 0 0a 0 0 0 0 0 0 p0 0 0 0 0 0 0 0 0 0
00 0 0 0 0 0 0 0 0 0 0 0 00 0 00 0 0 00 0 0 0




Fig. 2. Number of adult and larval thrips collected from pepper blooms, Delray Beach, FL 2006-07.







Florida Entomologist 92(1)


ICO(
ror


0o0
00
C) C


ME


irch 2009



120.0



1000


-Total Thnps

A -n-OriusX100
SThrips/Orius








A


/AV







/ pU-


rl- r- rl-
o o
o o


C) (N
Si ?


Fig. 3. Incidence of MPB, Orius insidiosus, in pepper blooms in Delray Beach, FL 2006-07. MPB counts are mul-
tiplied by 100.


winter reproductive diapause and were absent
from Dec through Apr, both in Delray Beach and
in Jupiter.
The distribution ofthrips larvae throughout the
crop cycle has economic importance. Larval num-
bers were low when FFT were abundant, yet larval
numbers nearly equaled WFT adult numbers dur-
ing the latter part of the season. The rapid increase
in WFT adults and especially the abundance of lar-
vae from Dec to Mar may be due in large part to the







E


1 /, 1 \


absence of MPB. Baez et al. (2004) found that lar-
vae of WFT are significantly more susceptible to
predation by MPB than adults.
Further contributing to the WFT population
explosion is frequent pyrethroid use. The explo-
sion occurred during a period of intense insecti-
cide use throughout the farming area, and many
applications of several pyrethroid insecticides
registered for use in peppers were made (GCC,
unpublished data). Economically damaging popu-










r A
10 ..,


Dr2O. OmoN W'WIm OQ3OVY


03'l7W N42om7


Fig. 5. Number of adult and larval thrips collected
from pepper blooms, Jupiter, FL 2006-07.


80.0



60 0



40.0



20 0


o I,3'O:S oD;14fl6 o[,i.,r ObItf iCA)36 0M'. fl.

Fig. 4. Number of adult and larval thrips collected
rom pepper blooms, Jupiter, FL 1996.







Frantz & Mellinger: Western Flower Thrips Abundance and Damage


1200



1000


41)
a. 800
E
(UI
(0
a 600
CL
M.
a.
.. 400
I--


05/08/07 05/10/07 05/14/07 05/16/07 05/21/07 05123/07 05/29/07


o UTC
* Permethrnn
c Gamma-cyhalothrin


o Methoxyfenozide
a Permethrin + Methoxyfenozide
s Gamma-cyhalothrin + Methoxyfenozide


Fig. 6. The impact of insecticides on adult and larval thrips infesting peppers, Fort Pierce, FL May 2007.


nations of the melon thrips, Thrip
have been observed in pepper crops
larly with pyrethroids, compared t
ing populations where pyrethroid us
(GCC, unpublished data). Similar e
throid insecticides on thrips number
reported from vegetable insect cor
Virginia (Kuhar et al. 2007).


S nsss
altr


.. .. .. .0 5o
Average MPB per sample

Fig. 7. Impact of minute pirate bugs (I
populations in peppers treated with in
Pierce, FL May 2007.


s palmi, also The most likely way that pyrethroid applications
treated regu- increase thrips populations is their toxicity to bene-
o non-damag- ficial organisms, specifically MPB. The average
*e is restricted numbers of thrips and MPB over all sampling dates
effects of pyre- in the Fort Pierce insecticide trial were clearly af-
ers have been fected by the pyrethroid insecticides, permethrin
itrol trials in and gamma-cyhalothrin (Table 1 and Fig. 7). The
most favorable ratio of thrips to MPB occurred in
the untreated check and methoxyfenozide treat-
ment (~28:1), followed by the permethrin treat-
ments (~75:1). The ratio in plots treated with
gamma-cyhalothrin was over 340 thrips per MPB,
clearly too high to allow biological control to occur.
The possible stimulation of WFT reproduction, hor-
moligosis, by pyrethroid insecticides must also be
considered, although such increased fecundity has
Been demonstrated among Thysanoptera only in
the citrus thrips, Scirtothrips citri (Morse & Zareh
1991). Considering the obvious impact of pyre-
throids on MPB, any significant hormoligotic im-
pact on WFT reproduction would synergistically ac-
M....C celebrate the rate of population increase.
In summary, WFT populations during the 2006-
07 survey in Delray Beach increased as popula-
tions of FFT and MPB declined, resulting in signif-
icant economic crop damage. Strategies to avoid
MPB) on thrips such losses in the future must focus on preserving
secticides, Fort MPB while minimizing the potentially detrimental
frequent use of pyrethroid insecticides.







34 Florida Ento



LITERATURE CITED

BAEZ, I., REITZ, S. R., AND FUNDERBURK, J. E. 2004. Pre-
dation by Orius insidiosus (Heteroptera: Anthoc-
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flower thrips (Thysanoptera: Thripidae) in pepper
flowers. Environ. Entomol. 33: 662-670.
FRANTZ, G., AND MELLINGER, H. C. 1990. Flower thrips
(Thysanoptera: Thripidae) collected from vegeta-
bles, ornamentals and associated weeds in south
Florida. Proc. Florida State Hort. Soc. 103: 134-
137.
FUNDERBURK, J. E., AND SALGUERO, V. E. 1989. Biology
and management of thrips and tomato spotted wilt
virus. Proc. Florida Tomato Inst., Vegetable Crops.
Special Series SS-VEC-901, 34-41.
GILLETT, J. L., HANSPETERSEN, H. N., LEPPLA, N. C.,
AND THOMAS, D. D. 2006. (EDS.) Grower's IPM Guide


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for Florida Tomato and Pepper Production. Univ. of
Florida, Institute of Food and Agricultural Sciences.
Gainesville, FL.
KIRK, W. D. J., AND TERRY, L. I. 2003. The spread of the
western flower thrips Frankliniella occidentalis
(Pergande). Agricultural and Forest Entomol. 5: 301-
310.
KUHAR, T. P., DOUGHTY, H., HITCHNER E. M., AND CAS-
SELL, M. 2007. Arthropod Pest Management Re-
search on Vegetables in Virginia-2007. Virginia
Polytechnic Institute & State University, Eastern
Shore AREC Report # 306
MCRITCHIE, J. J. 1986. Tomato Spotted Wilt. Florida
Dept. of Agr. and Consumer Services, Plant Path.
Circ. No. 287, 2 pp.
MORSE, J. G., AND ZAREH, N. 1991. Pesticide-induced
hormoligosis of citrus thrips (Thysanoptera: Thripi-
dae) fecundity J. Econ. Entomol. 84: 1169-1174.







Humeres et al.: Control of Avocado Lace Bug


EVALUATION OF NATURAL ENEMIES AND INSECTICIDES
FOR CONTROL OF PSEUDACYSTA PERSEAE (HEMIPTERA: TINGIDAE)
ON AVOCADOS IN SOUTHERN CALIFORNIA


EDUARDO C. HUMERES1, JOSEPH G. MORSE1'2, RICHARD STOUTHAMER'2, WILLIAM ROLTSCH3 AND MARK S. HODDLE'2
1Department of Entomology, University of California, Riverside, CA 92521 USA

2Center for Invasive Species Research, University of California, Riverside, CA 92521, USA

3 Biological Control Program, California Department of Food and Agriculture, Sacramento, CA 95832, USA

ABSTRACT

Three natural enemies naturally present in southern California avocado groves were eval-
uated against different stages of the avocado lace bug, Pseudacysta perseae (Heidemann), in
the laboratory. The natural enemies tested were adult females of a predatory thrips, Fran-
klinothrips orizabensis, second instar green lacewing larvae, Chrysoperla rufilabris, and a
predaceous mite, Neoseiulus californicus. The most promising natural enemy from labora-
tory and subsequent greenhouse evaluations was C. rufilabris. In addition to natural ene-
mies, insecticides were evaluated for P. perseae control. The contact impact of less persistent
materials on nymphs in the laboratory was assessed. The most effective insecticides based
on residual impact studies were carbaryl, imidacloprid, and fenpropathrin, and 2 materials
commonly used on avocados in California, abamectin and spinosad, which were ineffective.
Among the insecticides evaluated based on contact activity, a pyrethrin mixture was the best
treatment followed by petroleum oil and potash soap. The contact insecticides were evalu-
ated for their impact on second instars of C. rufilabris. The pyrethrin mixture was less toxic
to C. rufilabris, and because of its low mammalian toxicity this insecticide may be suitable
for use with natural enemy releases for homeowners to manage P. perseae populations on
backyard avocados.

Key Words: biological control, Chrysoperla rufilabris, Franklinothrips orizabensis, insecti-
cides, IPM, Neoseiulus californicus, Persea americana

RESUME

La eficiencia de tres enemigos naturales, naturalmente presents en huertos de aguacate en
el sur de California, para el control de diferentes estadios de desarollo (primer instar tardio
o segundo instar temprano ninfal, tercer instar ninfal y adults) de la chinche de encaje del
aguacate, Pseudacysta perseae (Heidemann), fueron evaluados sobre condiciones de labora-
torio y casa de vegetacion. Los enemigos naturales evaluados en laboratorio fueron hembras
adults de trips predadores, Franklinothrips orizabensis, larvas del segundo instar de criso-
pas verdes, Chrysoperla rufilabris, y hembras adults del fitoseido, Neoseiulus californicus.
El enemigo natural mas prometedor evaluado en laboratorio y subsequentemente en casa de
vegetacion fue C. rufilabris. Ademas del studio de enemigos naturales, fueron evaluados in-
secticidas en laboratorio para el control de P. perseae, el cual consistio en la experimentation
del impact residual de insecticides persistentes y de contact de insecticides menos persis-
tentes en ninfas. Los insecticides mas efectivos basados en los studios de impact residual
fueron carbaryl, imidacloprid y fenpropatrin. Abamectin y spinosad, dos products comun-
mente usados en aguacate en California, fueron ineficaces. Entre los insecticides investiga-
dos basados en su actividad de contact, una mezcla de piretrinas fue el mejor tratamiento
entire aquellos evaluados seguidos del aceite de petroleo yjab6n de potasio. Los insecticides
de contact tambien fueron evaluados por su impact sobre el segundo instar larval de C. ru-
filabris. La mezcla de piretrinas fue compatible con el uso de C. rufilabris y devido a su baja
toxicidad mamifero; este insecticide podria ser adecuado para ser usado en conjunto con li-
beraciones de enemigos naturales para proprietarios de vivienda con poblaciones significa-
tivas de chinche de ancaje del aguacate en aguacates en la propriedad.

Translation provided by the authors.


The avocado lace bug, Pseudacysta perseae ocados, Persea americana Miller (Lauraceae), in
(Heidemann) (Hemiptera: Tingidae), was first de- Florida. Pseudacysta perseae nymphs and adults
scribed in 1908 from specimens collected from av- feed in dense aggregated colonies on the under-







Florida Entomologist 92(1)


side of predominantly mature leaves, resulting in
development of large necrotic areas (Hoddle et al.
2005a). The exact impact of P perseae on produc-
tivity is not known, but fruit yields are likely re-
duced because of lower photosynthetic rates and
defoliation events that result from feeding dam-
age. Until recently, P perseae was considered a
pest of sporadic and minor economic importance
(Mead & Pena 1991). Population outbreaks of P.
perseae on avocados have been observed since the
mid 1990s in Florida and several countries in the
Caribbean, and P perseae has now emerged as a
serious foliar pest of avocados in the Caribbean
(Pena 2003). The known geographic range for P.
perseae in the Caribbean includes Jamaica, Pu-
erto Rico, the Dominican Republic, St. Lucia, St.
Thomas, St. John, St. Croix, and Cuba (Hoddle,
unpublished surveys). It has been recorded from
the states of Chiapas, Michoacan, Nayarit, Ver-
acruz, and Yucatan in Mexico, and in Escuintla
Guatemala (Hoddle, unpublished surveys). In
South America, P. perseae is known from Venezu-
ela and French Guyana (Mead & Pena 1991; Me-
dina-Gaud et al. 1991; Abreu 1995; Diaz 2003;
Hernandez et al. 2004; Hoddle et al. 2005a; Mo-
rales 2005; Sandoval & Cermeli 2005; Streito &
Morival 2005).
In the U.S., P perseae has been recorded from
the southeastern states of Florida, Georgia, Loui-
siana, and Texas (Hoddle et al. 2005b). In Sep
2004, P perseae was detected for the first time in
California on 2 residential backyard avocado
trees in Chula Vista and National City in San Di-
ego County. The trees were heavily infested and
exhibiting premature leaf drop because of feeding
damage (Bender & Witney 2005; Hoddle et al.
2005b). Subsequent surveys conducted by the San
Diego County Department of Agriculture,
Weights & Measures and the California Depart-
ment of Food and Agriculture during 2004-05
(winter) and 2006 (spring and fall) indicated that
this pest was restricted to residential areas in
southern San Diego County and had not estab-
lished in commercial avocado orchards in this
area or spread beyond San Diego County.
Three natural enemies that are common in
commercial avocado groves in southern California
are the predatory thrips, Franklinothrips oriza-
bensis Johansen (Thysanoptera: Aeolothripidae);
the green lacewing, ('C., .y-... Ii. rufilabris (Bur-
meister) (Neuroptera: Chrysopidae); and the pre-
daceous mite, Neoseiulus californicus (McGregor)
(Acari: Phytoseiidae) (Yee et al. 2001; Oevering et
al. 2003, 2005). These 3 species are commercially
available and are used augmentatively by some
growers in California for biological control of ei-
ther avocado thrips, Scirtothrips perseae Naka-
hara (Thysanoptera: Thripidae), or persea mite,
Oligonychus perseae Tuttle, Baker, and Abatiello
(Acari: Tetranychidae) (Kergulen & Hoddle 1999;
Hoddle et al. 2000b, 2004; Hoddle & Robinson


2004). It is unknown how readily these 3 natural
enemies might attack P. perseae and thus, 1 objec-
tive of this research was to evaluate the predation
activity of these 3 natural enemies against vari-
ous life stages ofP. perseae.
Pena (1992) conducted pesticide tests under
both laboratory and field conditions to determine
the efficacy of several insecticides for controlling
nymphs and adults of P perseae in Florida. Under
laboratory conditions, chlorpyrifos, permethrin,
malathion, and methomyl were effective in killing
adult P perseae. Field tests indicated that chlo-
rpyrifos, permethrin, malathion, and methomyl
significantly reduced adult P perseae populations.
Further studies by Pena et al. (1998) showed that
soap salts (M-Pede Insecticide Fungicide, 49% po-
tassium salts of fatty acids, Mycogen Corp., San
Diego, CA), citrus oil, and Mycotrol (Beauveria
bassiana conidia, Laverlam International Corpo-
ration, Butte, MT) all significantly reduced P per-
seae densities compared to levels on untreated
control trees.
To build upon this work by Pena (1992) and
Pena et al. (1998), the efficacy of an additional 5
residual and 6 contact insecticides registered for
home and commercial use in California were
tested against P perseae. The compatibility of
these insecticides was also tested against C. rufi-
labris, the most promising natural enemy evalu-
ated from the studies reported here. Conse-
quently, the objective of these studies was to iden-
tify efficacious natural enemies and insecticides
for use against P perseae that could form the
foundation for an IPM program for this pest in
California.

MATERIALS AND METHODS

Sources of Natural Enemies

Franklinothrips orizabensis larvae were pur-
chased from Buena Biosystems (Ventura, CA)
and were reared at the University of California,
Riverside, by procedures established by Hoddle et
al. (2000a) until bioassays were performed.
C'i .. y.... I i. rufilabris larvae were obtained from
Beneficial Insectary (Redding, CA) andN. califor-
nicus adults were purchased from Sterling Insec-
tary (Delano, CA). Upon receipt, C. rufilabris and
N. californicus were temporarily stored at 10.0-
13.0C for 24-48 h until used in bioassays.

Pseudacysta perseae Colony

Pseudacysta perseae was reared in 2 green-
houses (24.5 m3 each) at 25 + 5C, 60% RH, and
14:10 (L:D) lighting provided by 10 fluorescents
lights in each greenhouse (1.2 m long, 40 Watt,
3,200 lumen output per light; Phillips Homelight
Cool White Plus bulb, Philips Lighting Company,
Somerset, NJ). They were reared on potted avo-


March 2009







Humeres et al.: Control of Avocado Lace Bug


cado trees, with Bacon variety scions grafted to ei-
ther Duke 7 or Toro Canyon rootstock that were
approximately 1.5 years of age. Avocado trees
grown in the greenhouse in 57-L pots were in-
fested with P. perseae that had been field collected
from 5 different sites around San Diego County,
CA.

Natural Enemy Laboratory Bioassays

Franklinothrips orizabensis, C. rufilabris, and
N. californicus used in laboratory bioassays were
confined individually in small plastic vials (4.8 x
2.9 cm) with screened mesh lids and held at 25 +
5C and 80% RH without food for 24 h prior to use
in bioassays. After this starvation interval, natu-
ral enemies were transferred to modified Munger
cells (Munger 1942; Morse & Brawner 1986),
which contained a clean, fully expanded, Hass av-
ocado leaf as the foraging substrate. For the F.
orizabensis and C. rufilabris trials, each Munger
cell was inoculated with 1 of 3 lace bug life stages
1 h prior to the introduction of either a single
adult female predatory thrips or a single second
instar lacewing. The 3 life stages evaluated were
5 late first or early second instars ofP. persea, 5
third instars, or 5 adults. For studies with N. cal-
ifornicus, only eggs and 2 nymphal lace bug
stages (early first instars and early second in-
stars) were tested due to the small size of this
predator. One adult female N. californicus was
placed in each Munger cell with 5 early first in-
stars, early second instars or a mass of 14.9 + 0.7
(SD) eggs. Leaves with eggs were collected from
the P. perseae colony and were used in the Mu-
nger cells. Each treatment was replicated 10
times for each predator and P. perseae life stage
evaluation, a paired control was set up to mea-
sure naturally-occurring mortality, and the con-
trol treatment consisted only of the P. perseae life
stage that was being evaluated.
Munger cells were held at 25 5C, 80% RH,
and 14:10 L:D in a temperature controlled cabi-
net. After 24 h, the number of dead and live P per-
seae was recorded. Pseudacysta perseae test mor-
tality was corrected for control mortality by Ab-
bott's formula (Abbott 1925) after pooling data for
the 10 Munger cell replicates from each natural
enemy and prey treatment.
A second study was conducted to evaluate the
efficacy ofN. californicus against P perseae eggs.
Fully expanded avocado leaves (variety Bacon)
with P perseae eggs were removed from the
greenhouse colony, the number of eggs counted,
and an average of 34.9 6.8 eggs were set up in
each Munger cell. Predatory mites were starved
for 24 h and then 1 adult female was transferred
to the Munger cell containing the P perseae egg
mass. Munger cells with P. perseae egg masses
and predatory mites were held in a temperature
cabinet (25 5C, 80% RH, 14:10 L:D) and were


visually assessed for predation events immedi-
ately after the last Munger cell was prepared (60
min after the first cell was set up). Predaceous
mite behavioral events were recorded as follows:
(1) making contact and investigating the egg
mass with the forelegs; (2) feeding on eggs; (3)
resting (predator was stationary for >15 s);
grooming (predator was engaged in cleaning ac-
tivities), and (4) searching (predator walked
around the experimental arena). Altogether, 20
replicates were completed, at a rate of 5 replicates
per day over 4 consecutive days. Predator behav-
iors were recorded during 60 min of observing
each of the 5 Munger cells one at a time for 2 min,
and returning to observe each cell every 10 min.
Six-observation intervals were produced per cell
per day. Observations were pooled and percent-
ages for each behavior of interest were calculated.

Statistical Analyses for Laboratory Natural Enemy Bio-
assays

SAS Version 8.2 for Windows (SAS Institute
Inc., Cary, NC) was used in all analyses, test mor-
tality was corrected for control mortality with Ab-
bott's formula (Abbott 1925), and all tests were
performed at the 0.05 level of significance. In the
F orizabensis bioassay, Fisher's exact test was
used to compare the mortality between medium
size nymphs and adults of P perseae. Student's t-
test was used to compare P. perseae mortality be-
tween late first or early second instars and third
instars in the same bioassay. With the C. rufila-
bris bioassay, a logistic regression model with the
Bonferroni adjustment was used to compare P.
perseae mortality among the 3 lace bug develop-
mental stages. In the N. californicus bioassay
with the 3 P. perseae life stages (eggs, early first
instars, and early second instars), proportional
mortality inflicted on the life stages was com-
pared with Fisher's exact test. In the test observ-
ing N. californicus behaviors when exposed to P.
perseae eggs, a multinomial proportion test was
used to compare behaviors but excluded "feeding
on eggs" because proportions equal to zero oc-
curred with high frequency (Agresti 2002). There-
fore, the comparison of "feeding on eggs" against
all other behaviors was performed by Fisher's ex-
act test.

Evaluation of C. rufilabris for P. persea Control on Small
Potted Avocado Trees

The Munger cell bioassays indicated that the
most effective commercially available natural en-
emy evaluated for control of P perseae was the
larval stage of C. rufilabris (see Results and Dis-
cussion). Consequently, this life stage was used in
the next tier of evaluation, testing efficacy against
P perseae on 20 small potted "Bacon" avocado
trees in a greenhouse. Second instars ofC. rufila-







Florida Entomologist 92(1)


bris were starved for 24 h prior to use in these tri-
als. Each of the 20 uncaged trees was infested
with 10-15 medium-sized P. perseae, which were
transferred to a single leaf and then left for 1 h to
acclimate and commence feeding. Following accli-
mation, the number of live P perseae nymphs suc-
cessfully transferred to each leaf was recorded
(the pre-count). At this time, 10 randomly se-
lected trees were each inoculated with 3 second
instars ofC. rufilabris with 1 larva placed individ-
ually on each of 3 randomly selected leaves on the
test plant. The remaining 10 trees served as con-
trols without predators. Uncaged experimental
trees were separated so that leaves of adjacent
plants did not touch. Two white foam boards
(Royal Brites Foam Board with Grid, Office De-
pot, Delray Beach, FL, size 51 x 76 cm) were
placed underneath each tree to collect any C. rufi-
labris larvae and P. perseae nymphs that fell from
experimental trees. Part of each board was re-
moved so the 2 boards could be joined around the
tree trunk and held together with binder clips.
Tanglefoot (The Tanglefoot Co., Grand Rapids,
MI), a sticky insect barrier, was applied liberally
along the edges of the foam boards to prevent the
escape of any insects that dropped onto the
boards. Predators were left to forage for 48 h. This
greenhouse trial was replicated 2 times (Nov 15
and 22, 2006) for a total of 20 predator inoculated
trees and 20 control trees.
After 48 h, all leaves were stripped from each
experimental tree and the total number of dead
and live P. perseae nymphs and C. rufilabris lar-
vae per tree was recorded. Pseudacysta perseae
test mortality was corrected with Abbott's for-
mula with control mortality pooled across the 10
control trees and with pooled nymphal mortality
data for the 10 trees with lacewing larvae within
each trial.
Student's Standardized t-test was used to de-
termine if treatment and control mortality were
significantly different between replicated green-
house trials in order to allow us to pool the data
for statistical analysis. No statistically significant
differences were observed, and Logistic Regres-
sion was used to analyze pooled data.
Removed leaves were photocopied and the to-
tal leaf area for each experimental tree was deter-
mined with a leaf area meter (LI-COR area meter,
model LI-3100, LI-COR, Inc., Lincoln, NE). Aver-
age leaf area for control and treated avocado trees
for each greenhouse trial were compared with
Student's Standardized t-test. All statistical tests
on data from the greenhouse experiment were
conducted at the 0.05% level of significance.

Pesticides Used in Bioassays

In the pesticide screening research with P per-
seae, we evaluated the residual impact of several
persistent pesticides and the contact effect of sev-


eral less persistent and less toxic materials. The
pesticides evaluated in the residual impact trial
were commercial formulations of the following
materials applied at label rates: (1) carbaryl at
8.34 g active ingredient (AI) per L of water (Gar-
denTech-Sevin Concentrate Bug Killer, 22.5%
carbaryl (0.237 kgAI per L) TechPac LLC, Lexing-
ton, KY); (2) soil-applied imidacloprid at 1.01 g AI
per pot mixed with 378.5 mL of water and applied
uniformly over the soil surface of each pot (Bayer
Advanced Tree and Shrub Insect Control Concen-
trate, 1.47% (15.28 g AI per L) imidacloprid,
Bayer Advanced LLC, Birmingham, AL; the label
rate is 29.57 mL per 2.54 cm of trunk circumfer-
ence; the 10 seedlings used for this treatment had
an average trunk circumference of 5.66 + 0.53 cm
(SD); (3) spinosad at 0.375 g AI per L of water
(Success 2SC, suspension concentrate), 239.7 gAI
per L, Dow AgroSciences LLC, Indianapolis, IN;
(4) abamectin at 0.014 g AI per L of water (Agri-
Mek 0.15 EC, emulsifiable concentrate), 18.0 g AI
per L, Syngenta Crop Protection, Inc., Greens-
boro, NC); (5) 15% petroleum oil (1.5 mL Loveland
415 spray oil per L of water, Loveland Products
Inc., Greeley, CO); and (6) fenpropathrin at 0.479
g AI per L of water (Danitol 2.4EC Spray, emulsi-
fiable concentrate), 287.6 g AI per L, Valent USA
Corp., Walnut Creek, CA). In the spinosad and ab-
amectin treatments, petroleum oil was added at a
rate of 1% to improve their performance as per
manufacturer recommendations. The efficacy of
insecticide treatments was compared to water
treated control plants.
The contact insecticides evaluated included:
(1) 0.156 mL pyrethrins per L of water (PyGanic
EC 1.4 II, 1.4% pyrethrins, MGK Corp., Minneap-
olis, MN); (2) 0.391 mL pyrethrins + potash soap
per L of water (SAFER BRAND Yard & Garden
Insect Killer II Concentrate, 0.012% pyrethrins
and 1.015% potassium salts of fatty acids, Safer
Inc., Lilitz, PA); (3) 0.025 mL pyrethrins + roten-
one per L of water (Pyrellin E.C., 0.6% pyrethrins
+ 0.5% rotenone + 0.5% associated resins, Webb
Wright Corp., Ft. Myers, FL); (4) 0.078 mL neem
oil per L (Green Light Neem Concentrate, 70%
clarified hydrophobic extract of neem oil, Green
Light Co., San Antonio, TX); (5) 1.5 mL petroleum
oil per L of water (Loveland 415 spray oil); and (6)
0.391 mL potash soap per L of water (M-Pede In-
secticide Fungicide, 49% potassium salts of fatty
acids, Mycogen Corp., San Diego, CA). This sec-
ond set of insecticides was used at the same rates
to test the contact impact on C. rufilabris. The ef-
ficacy of tested contact insecticides was compared
to water treated control plants.

Residual Impact Effect of Insecticides on P. perseae

In this trial, each of the foliar insecticides and
a water control were sprayed with a hand sprayer
(Prime Line Sprayer Model N100-S, B&G Equip-


March 2009







Humeres et al.: Control of Avocado Lace Bug


ment Co., Jackson, GA) to apply ca. 0.7 L of spray
to 10 avocado Hass seedlings. Plants were
sprayed to runoff and were then left exposed to
outside weather conditions. The exception was
the imidacloprid treatment, which was applied to
the soil after the pesticide was diluted in 3.8 L of
water and applied in equal amounts to the 10 ex-
perimental avocado seedlings. The plants were
1.0 to 1.5 m tall and soil volume in the pots was
approximately of 0.0092 m3. New flush leaves
were trimmed off the seedlings as they appeared
so they would not be later confused with treated
leaves (i.e., all leaves on the tree at the time of
treatment). Leaves were sampled to evaluate P.
perseae mortality 3, 7, 14, 28, 49, 77, and 112 d af-
ter treatment (2 treatments were dropped from
evaluation after d 7 as P perseae mortality
dropped below 10%). Bioassays were conducted
by placing each of 10 treated leaves per treatment
into a Munger cell, transferring 10 medium size P.
perseae nymphs into the cell, and evaluating their
mortality after 72 h.
Fisher's exact test was used to analyze pesti-
cide data to test if the proportional mortality be-
tween treatments was significantly different. On
d 3, six treatments: carbaryl (T2), imidacloprid
(T3), spinosad + oil (T4), abamectin + oil (T5), pe-
troleum oil (T6), and fenpropathrin (T7), were
subjected to pairwise comparisons and significant
differences between treatments comparisons
were determined with the Bonferroni adjustment
at the 0.05 level of significance.

Contact Impact of Insecticides on P. perseae and C. rufi-
labris

Two separate bioassays were performed to de-
termine the contact effect of insecticides, 1 bioas-
say each with P perseae nymphs and second in-
star C. rufilabris. The insecticides were applied
directly to avocado leaves with 10 P. perseae
nymphs or a single C. rufilabris larva with a
118.3-mL fine plastic mist spray bottle (Sally
Beauty Supply, Marianna, Denton, TX). Approxi-
mately 5.8 mL of spray was applied to the 10
leaves per treatment in aggregate. After each
spray, the 10 P perseae or single lacewing larva


were transferred to a Munger cell with a clean av-
ocado leaf. Ten or 15 replicate Munger cells were
used for the P perseae or lacewing bioassays, re-
spectively (100 P. perseae or 15 lacewings in total).
Excess P perseae nymphs were placed in the Mu-
nger cells for the C. rufilabris larva to feed on.
Mortality was evaluated 72 h after treatment for
both P perseae and C. rufilabris bioassays. The P.
perseae bioassay was conducted once and the C.
rufilabris bioassay was replicated on 2 dates.
Two analyses were used with P perseae data to
determine statistical separation between control
mortality and mortality observed with the contact
pesticides. Logistic Regression was used to test
for significant differences between control mortal-
ity and mortality with the pyrethrins + potash
soap, petroleum oil, and potash soap treatments
(i.e., the 2 treatments resulting in 100% and 0%
mortality were excluded). Fisher's exact test was
used for testing differences between the pyre-
thrins + potash soap and pyrethrins + rotenone
treatments.
In the C. rufilabris bioassay, analyses failed to
detect significant differences between the tests
done on the 2 bioassay dates and data were pooled
with final analyses using a Two Factor Logistic
Regression with the Bonferroni Adjustment.

RESULTS AND DISCUSSION

Second instar C. rufilabris were the most effi-
cacious natural enemy tested in the laboratory
and caused the highest mortality of third instars
of P. perseae (Table 1). The predatory thrips F
orizabensis successfully attacked and killed 60%
of late first or early second instars of P perseae
but had limited impact on third instars and failed
to kill adults (Table 1). The least effective natural
enemy was the predaceous mite N. californicus,
and it showed little ability to inflict substantial
mortality against any of the P perseae life stages
tested (Table 2). A second predatory mite study
with P perseae eggs was designed because evalu-
ating the number of unhatched eggs after 24 h in
the first study was inconclusive as it was difficult
to determine whether or not predators had fed on
and killed eggs. The second study indicated lim-


TABLE 1. MORTALITY OF VARIOUS LIFE STAGES OF PSEUDACYSTA PERSEAE (ALB) AFTER EXPOSURE TO CHRYSOPERLA
RUFILABRIS OR FRANKLINOTHRIPS ORIZABENSIS.

Corrected % mortality Corrected % mortality
Treatment after exposure to C. rufilabris' after exposure to F orizabensis1

Late first or early second ALB instars 60.0 b 60.0 a
Third ALB instars 96.0 a 6.0 b
ALB adults 71.4 b 0.0 b

Means followed by the same letter within a column are not significantly different (P = 0.05).







Florida Entomologist 92(1)


TABLE 2. MORTALITY OF PSEUDACYSI
NYMPHS AFTER EXPOSURE
CALIFORNICUS.

Treatment Corrected

Unhatched eggs
ALB first stage nymphs
ALB small stage nymphs

1Means followed by the same letter are
ferent (P > 0.05)
Mortality of eggs was not statistically
other treatments because of high control
trial was designed for this life stage.


ited predator mite responses to
masses with mites observed in the
only 2.5% of the time and with
feeding (Fig. 1). Because second
bris attacked all P perseae life st;
predator was selected for furt
against P. perseae on small potte
in the greenhouse.
In the greenhouse study, the
of P perseae nymphs artificially
experimental trees (pre-count)
control trees and on those in whicl
ing second instars were released (
tal leaf area for the first and secor
the green lacewing treatment sh
cant difference between both lea
and 3,608.1 cm2 for the first and s
respectively) and mortality. Their
pooled for further analysis. Mort
star P perseae on potted avocado
nificantly different between cont
ing C. rufilabris and those treated


2.5d


Exploring egg Feeding on Resing
mass eggs
Behavioral Eveni
Fig. 1. Behavior ofNeoseiulus calif
sented with Pseudacysta perseae eggs
Means followed by the same letter ar
ferent (P > 0.05).


'A PERSEAE (ALB) bris larvae (W = 42; df = 1; P < 0.005). The com-
TO NEOSEIULUS bined mortality (dead and missing, Table 3) for
third instar P. perseae for the lacewing treatment
was 14.9, 2.2 times higher than that observed for
% mortality' the control treatments (6.9 dead P persea
nymphs).
11.C32. *. .'..' ,/.I rufilabris has been demonstrated
0.0 a previously as an effective natural enemy against
1.7 a azalea lace bug, Stephanitis pyrioides (Scott)
not significantlydif (Hemiptera: Tingidae), a serious cosmopolitan
not significantly dif-
pest of ornamental landscape azaleas (Shrews-
Sanalyzed with the bury & Smith-Fiola 2000; Stewart et al. 2002). In
mortality. A second nursery trials, augmentative releases ofC. rufila-
bris onto potted azalea bushes reduced damaging
S. pyrioides densities by 97%. This level of control
P. perseae egg was comparable to standard industry insecticide
e vicinity of eggs treatments (i.e., acephate) and lacewing larvae
no observed egg could thus be considered a potential control tactic
instar C. rufila- for use within an IPM framework for S. pyrioides
ages tested, this management (Shrewsbury & Smith-Fiola 2000).
her evaluation Many homeowners and commercial avocado
d avocado trees growers in California are interested in non-chem-
ical control measures for avocado pests, especially
average number the use of natural enemies. Results from labora-
infested on the tory assays and small potted plant trials in the
was similar on greenhouse indicated that commercially available
h 3 green lacew- C. rufilabris may have potential for reducing P.
Table 3). The to- perseae densities on small avocado trees. How-
nd replication of ever, more comprehensive tests across a variety of
owed no signifi- tree sizes, pest infestation levels, and climates
if area (4,166.6 (i.e., arid interior avocado growing areas of Cali-
econd replicate, fornia vs. cooler more humid coastal zones) that
before, data were approximate more realistic field conditions are
ality of third in- needed before recommendations for the use of this
plants was sig- predator can be made.
rol plants lack- The residual impact of 6 relatively persistent
d with C. rufila- insecticides on P perseae nymphs is shown in Ta-
ble 4. Carbaryl, imidacloprid, and fenpropathrin
were the strongest treatments evaluated. Car-
baryl was effective from 3 to 112 d post-treat-
ment. Mortality of P perseae on imidacloprid
a treated seedlings increased from 75 to 97 to 100%
after 1, 2, and 4 weeks post-treatment as the soil-
applied material was taken up by the small potted
trees. This treatment remained effective through
the 112-d post-treatment evaluation. Fenpropath-
rin was effective early in the trial but mortality of
lace bugs declined following the 77-d post-treat-
ment evaluation. Spinosad plus oil and abamectin
plus oil were eliminated as candidate treatments
11.2 after P perseae mortality dropped below 10% with
the 7-d post-treatment bioassay. These 2 materi-
als are widely used on California avocados for
control of pest thrips and mites, and our results
Grooming Exploing contradict the suggestion by Bender & Witney
arena (2005) that these materials would be effective on
Is avocado lace bug. The reason for lack of activity by
rnicus when pre- spinosad and abamectin is not understood but
in the laboratory. could be due to the feeding behavior of P perseae,
e significantly dif- or the mode of action of these pesticides may be
ineffective against this pest.


March 2009







Humeres et al.: Control of Avocado Lace Bug


TABLE 3. MORTALITY OF PSEUDACYSTA PERSEAE (ALB) NYMPHS ON SMALL POTTED AVOCADO TREES INOCULATED
WITH CHRYSOPERLA RUFILABRIS LARVAE.

Live Dead Total Individuals
Treatment Pre-count (L) (D) (L + D) not recovered

ALB on lacewing release seedlings 36.4 0.9 21.5 1.6 4.1 0.8 25.6 1.3 10.8 1.1
Number of green lacewing larvae 3.0 0.0 0.6 0.2 0.0 0.0 0.6 0.2 2.4 0.2

ALB control seedlings 42.0 1.8 35.1 2.3 1.0 0.3 36.0 2.4 5.9 1.4



TABLE 4. RESIDUAL IMPACT OF PERSISTENT INSECTICIDES ON PSEUDACYSTA PERSEAE NYMPHS.

Corrected % mortality'

Number of days after treatment

Treatment 3 7 14 28 49 77 112

Carbaryl 100 a 100 a 100 a 100 a 100 a 100a 100 a
Soil applied imidacloprid 23.0 b 75.0 b 97.1 a 100 a 100 a 100 a 100 a
Fenpropathrin 100 a 100 a 100 a 100 a 100 a 97.5 a 36.3 b
Abamectin + oil 36.0 b 9.9 c -
Spinosad + oil 9.0 c 1.0 d
Petroleum oil2 0.0 d 0.0 d

Means followed by the same letter within a column are not significantly different (P > 0.05).


The contact effects of the 6 less persistent and
less toxic insecticides on P. perseae nymphs and C.
rufilabris are shown in Table 5. For P. perseae
nymphs, the pyrethrin mixture was the most ef-
fective treatment of those evaluated followed by
potash soap, petroleum oil, and pyrethrins + pot-
ash soap. The pyrethrins + rotenone and neem oil
had little impact on P perseae nymphs. Petroleum
oil had no effect as a residual pesticide as shown
in our residual impact bioassay, but the contact
impact on P perseae was high. The results for the
insecticide-predator bioassay showed that the pe-
troleum oil treatment caused the highest C. rufi-
labris mortality. No significant difference was ob-
served among results for contact mortality of C.
rufilabris with potash soap, pyrethrins + potash
soap, pyrethrins, pyrethrins + rotenone, neem oil,
and the water control (Table 5).
In conclusion, experimental results presented
here suggest that of the 3 commercially available
natural enemies tested against P. perseae, the lar-
val stages of C. rufilabris were the most effica-
cious. However, field experiments are needed to
confirm the efficacy and cost effectiveness of C.
rufilabris larvae against P perseae. Of the persis-
tent insecticides evaluated for P perseae control,
imidacloprid and carabaryl were the most effec-
tive. For the less persistent insecticides, products
with pyrethrins were among the most effective
evaluated and these showed high compatibility
with C. rufilabris larvae. Results of work reported
here have helped develop the foundation of an


TABLE 5. ACTIVITY OF CONTACT INSECTICIDES ON PSEU-
DACYSTA PERSEAE AND CHRYSOPERLA RUFILA-
BRIS 72 H AFTER TREATMENT.

Percent mortality'

Treatment P. perseae C. rufilabris

Pyrethrins 100 a 23.3 b
Petroleum oil 74.0 b 70.0 a
Potash soap 73.7 b 26.7 b
Pyrethrins + potash soap 66.1 b 26.7 b
Pyrethrins + rotenone 41.2 c 20.0 b
Neem oil 0.0 d 13.3 b
Water control 6.7 b

Means followed by the same letter within a column are not
significantly different (P > 0.05).


IPM program should P. perseae emerge as a sig-
nificant avocado pest in California.

ACKNOWLEDGMENTS

We thank David Kellum, Ha Dang, Linda Feeley (all
in the San Diego Co. Ag. Commissioner's Office); Gary
Bender (University of California [UC] Cooperative Ex-
tension, San Diego Co.); and Guy Witney (California Av-
ocado Commission) for assistance with our avocado lace
bug research. Javier Suarez Espinosa (Doctoral student
in Applied Statistics, UC Riverside) provided help with
statistical analyses. This research was supported in
part by grants provided by the UC Exotic Invasive Pests











and Diseases Research Program (funding via USDA CS-
REES), the UC Hansen Trust Research Competitive
Grant Program, California Department of Food and Ag-
riculture, and the California Avocado Commission.

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Florida Entomologist 92(1)







Tormos et al.: Mature Larvae of Bembix bidentata and its Parasitoids



DESCRIPTION OF THE MATURE LARVA OF THE
SAND WASP BEMBIX BIDENTATA AND ITS PARASITOIDS
(HYMENOPTERA: CRABRONIDAE, CHRYSIDIDAE, MUTILLIDAE)


JOSEP TORMOS, JOSEP DANIEL Asis, AMPARO BENEITEZ AND S. F. GAYUBO
Unidad de Zoologia, Facultad de Biologia, Universidad de Salamanca, 37071-Salamanca, Spain
E-mail: tormos@usal.es

ABSTRACT

The mature larvae ofBembix bidentata and one of its chrysidid and mutillid parasitoids are
described and illustrated, and structures of phylogenetic value are discussed. The mature
larva of B. bidentata is characterized by an integument with short setae (< 40 im) and
scanty microspinules. The ratio between the length of the antennal papilla and the width of
the antennal orbit is a character state that can be used in the separation of the final instar
of European Bembix species. The mature larva of Chrysidea disclusa is characterized by a
combination of two character states: (1) an atrium without asperities or weak lines on the
circumference, and (2) antennal papillae longer than broad; the larval morphology of
Chrysidea previously was unknown. The mature larva of Chrysura hybrida is characterized,
within the genus Chrysura, by the autapomorphy maxillaryy palpus with 4 sensilla at apex."
The range of hosts of Chrysura spp. is broadened to the Crabronidae. The mature larva of
Smicromyrme rufipes is characterized, within the Mutillinae, by having more than 8 apical
setae and no apical papillae on the labium.

Key Words: Preimaginal stages, Bembix, Chrysidea, Chrysura, Smicromyrme

RESUME

Se described e ilustran, a la vez que se discuten estructuras de valor filogen6tico, la larva
madura de Bembix bidentata y las de sus crisididos y mutilidos parasitoides. La larva ma-
dura de B. bidentata se caracteriza por presentar el tegumento con setas cortas (< 40 im) y
escasas microespinulas. La relaci6n entire la longitud de la papila antenal y la anchura de la
6rbita antenal es un estado de caricter que podria utilizarse en la separaci6n de los estados
larvarios de las species europeas de Bembix. La larva madura de Chrysidea disclusa se ca-
racteriza por presentar la combinaci6n de los siguientes estados de caricter: (1) atrium sin
asperezas o lines sobre la circunferencia y (2) papila antenal mas larga que ancha; la mor-
fologia larvaria de Chrysidea era desconocida. La larva madura de Chrysura hybrida se ca-
racteriza, dentro del g6nero Chrysura, por presentar la autapomorfia: palpos maxilares con
4 sensilas en el apice; el rango de hospedadores de Chrysura se amplia a los Crabonidae. La
larva madura de Smicromyrme rufipes se caracteriza, dentro de los Mutillinae, por presen-
tar mas de 8 setas, y no presentar papilas, sobre la zona apical del labio.


Translation by the authors.


From a study on parasitoid-host interactions
within the Hymenoptera, carried out in Soria
(Spain) since 1999, we collected data on 2 species
of Chrysididae and 2 species of Mutillidae that act
as parasitoids of a species of Crabronidae. The fol-
lowing host/parasitoid combinations were found:
Bembix bidentata Vander Linden, 1829 (host)/
parasitoids: (a) Chrysididae: C'i, 'i *.....' disclusa
(Linsenmaier, 1959) and C(' ....... hybrida (Lepe-
letier, 1806); (b) Mutillidae: Smicromyrme rufipes
(Fabricius, 1787) and Nemka viduata (Pallas,
1773). Additionally, we obtained the mature lar-
vae of the host and of the 4 parasitoid species.
The Crabronidae (sensu Melo 1999) form a
broad family of Hymenoptera Aculeata in which
the Bembicinae, with more than 1700 species (Pu-
lawski 2007), represent one of the most numerous


subfamilies. Although several authors (among
them Evans & Lin 1956; and Evans 1959; 1964,
1987 are relevant) have studied the preimaginal
stages of this subfamily, the number of species for
which the mature larva has been described is very
low, with larvae of a fair number of genera re-
maining unknown.
Bembix Fabricius includes around 350 species
(Pulawski 2007), more than 50 being present in
the Palearctic Region (Asis et al. 1992). Neverthe-
less, studies on larval morphology are scarce, and
descriptions of the mature larva have been pro-
vided only for 24 species, of which 9 are Palearctic
(Grandi 1926a, b, 1928; Evans & Lin 1956; Evans
1959; 1964; lida 1979; Asis et al. 1989, 1992,
1997). In this paper we describe the morphology
of the last instar of B. bidentata. This instar is il-







Florida Entomologist 92(1)


lustrated and compared with the previously de-
scribed mature larvae of European species of this
genus.
"Cuckoo wasps" (Chrysididae) are very com-
mon parasitoids or kleptoparasites of many fosso-
rial Hymenoptera. Of this family, which includes
about 2430 species (Kimsey & Bohart 1990), the
mature larvae of 25 species have been described
appropriately (Tormos et al. 2001, 2003, 2006,
2007), of which 2 belong to the genus CL', ..1...
Dahlbom (Tormos et al. 2001). The larval mor-
phology of C'.l, i ...., Bischoff was unknown. In
the present work the mature larvae ofC. disclusa
and Ch. hybrida are described, illustrated, and
compared with the previously described mature
larvae of the closest taxa.
The Mutillidae are ectoparasitoids of larval in-
stars and they usually attack the postdefecated
larvae or pupae of other insects, generally ac-
uleate Hymenoptera (Brothers et al. 2000). Al-
though the family includes more than 9000 spe-
cies (Pitts & Matthews 2000), few studies have
addressed its preimaginal stages and biology.
Thus, with respect to their larval phases, only the
mature larvae of 7 species or subspecies have
been described accurately enough to be used for
comparative purposes (Tormos et al. 2003). In this
paper, we report the morphological character
states corresponding to the postdefecating ma-
ture larva of S. rufipes that are essential for as-
sessing the greater or lesser affinity of this genus
with the closest genera. The prepupa of this spe-
cies had been described by Grandi (1961). A de-
scription of the mature larva of N. viduata, of
which specimens were also obtained in the
present study, has been given in Tormos et al.
(2003).

MATERIALS AND METHODS

Mature larvae ofB. bidentata and of its parasi-
toids C. disclusa, Ch. hybrida, and S. rufipes were
obtained at Rabanera del Campo (Soria, Spain) in
Jun, 2003 (larvae of Ch. hybrida); Sep, 2003
(prepupae of S. rufipes); Jun, 2004 (larvae of C.
disclusa), and Jun, 2006 (larvae ofB. bidentata).
The material for morphological studies was fixed
and preserved in 70% EtOH. The remaining lar-
vae and cocoons were placed in terrariums with a
sandy bed and with cells similar to the original
ones from which they had been obtained. In the
terrariums, kept under environmental conditions
of temperature, RH and photoperiod, we obtained
adults to determine the species. The method em-
ployed for preparing the larval specimens and the
terminology of larval morphology and format
used in the descriptions follow those ofAsis et al.
(1997) and Tormos et al. (2001). The following ab-
breviations are used: d = diameter, h = height, 1 =
length, and w = width. The descriptions are based
on 2 mature larva (Bembix bidentata) and 1 ma-


ture larva (one each of the species of Chrysididae
and Mutillidae). Voucher specimens are deposited
at the "Torres-Sala" Entomological Foundation
(Valencia, Spain).

RESULTS

Descriptions of Larvae

Bembix bidentata Vander Linden, 1829,
(Figs. 1-5)

General Aspect (Fig. 1). Fusiform body (1 = 2.20
cm, w (maximum) = 1 cm), thinner towards the
anterior end. Anus terminal, as a transverse slit,
with the supra-anal lobe slightly larger than in-
fra-anal one. Pleural lobes well developed. Integ-
ument with scanty and disperse setae (1 = 25 pm)
and microspinules (1 = 5 pm). Spiracles (Fig. 2)
(d = 170-180 pm, n = 12) with atrium walls lined
with concentric rows of asperities; the prothoracic
ones slightly larger than the others. Opening to
subatrium with branched spinules. Cranium
(Fig. 3) (w = 1.4 mm, h (from the apex of clypeus)
= 1.5 mm) with scattered, small setae (1 = 10 pm);
placoid sensilla close to the insertion of the man-
dibles. Coronal suture very conspicuous; parietal
bands absent. Antennal orbits circular (d = 95
pm); antennal papillae (1 = 32 x 30 pm) well devel-
oped, with 3 apical sensilla. Clypeus with setae
(1 = 10 pm) and sensilla (d = 5-10 pm). Labrum
(Fig. 4a) (w = 650 pm; h = 190 pm) slightly emar-
ginate, with around 28 setae (1 = 20-30 pm) and 38
placoid (w = 20 pm) and 10-12 cupuliform (15 x 20
pm) sensilla, the latter located on the apical mar-
gin. Epipharynx (Fig. 4b) spinulose (1 of spinules
= 20 pm), with 2 central sensory areas, one on
each side, without spinules and pigmented, with 6
placoid sensilla; 4 sensilla in the central anterior
region. Mouthparts. Mandibles (Fig. 3) (1 = 600
pm, w at the base = 400 pm) tri-quadridentate,
without setae. Maxillae (Fig. 5b) (1 = 380 x 360
pm) with a very spinulose lacinial area, and a se-
tose (1 of setae = 25 pm) external side. Galeae
(170 x 35 pm) horn-shaped, slightly smaller than
maxillary palpi (1 = 175, w = 60 pm). Maxillary
palpus with 5 sensilla at apex, 4 cupuliform and
one placoid. Labium (Fig. 5a) (w = 340 pm) spinu-
lose on oral face, and with setae on lower part. La-
bial palpi (1 = 140, w = 40 pm) shorter than sali-
vary orifice (1 = 160 pm), with 5 sensilla at apex, 4
cupuliform and one placoid.

Chrysidea disclusa (Linsenmaier, 1959),
(Figs. 6-13)

General Aspect (Figs. 6, 10): Body robust (1 =
0.5 cm, w = 0.2 cm; abdominal segments divided
into 2 annulets by a transverse crease. Anus ter-
minal, as a transverse slit. Pleural lobes devel-
oped. Integument with scattered setae (1 = 9 pm).


March 2009







Tormos et al.: Mature Larvae of Bembix bidentata and its Parasitoids


1 a b b a
1 5 4
1 cm 0.1 cm 0.2 mm

Figs. 1-5, Mature larva ofBembix bidentata: (1) general aspect; (2) prothoracic spiracle (atrium, opening to sub-
atrium, and tracheal trunk); (3) cranium (frontal view); (4a) labrum; (4b) epipharynx; (5a) labium; (5b) maxilla.


Spiracles (Figs. 7, 11, 12): (d first pair = 60 prm,
rest = 40-55 pm, 5 (rest) = 52 pm, n = 12) with per-
itreme; atrium and opening into subatrium sim-
ple, naked; subatrium with 9-15 swellings. Cra-
nium (Figs. 8, 13): (w = 650 pm, h = 500 pm) with
scarce setae (1 = 10-15 pm) arranged symmetri-
cally. Coronal suture very well developed, parietal
bands absent. Antennal orbits inconspicuous; an-
tennal papillae (Fig. 13a) (1 = 50 pm, w = 10 pm)
long, below middle of cranium, with three apical
sensilla. Clypeus with 10 setae (1 = 10-20 pm) and
2 sensilla (w = 5 pm). Labrum (Figs. 9a, 13b) (w =
400 pm; h = 170 pm) emarginate, with around 26
setae (1 = 10-20 pm). Epipharynx (Fig. 9b) with 12
sensilla (d = 5 pm). Mouthparts: Mandible (Fig. 8)
(1 = 450 pm, w = 200 pm) quadridentate, with
teeth on different planes. Maxilla (1 = 270 pm, w =
100 pm) with 3 setae (1 = 15 pm) on external part.
Maxillary palpus (12 x 8 pm) with 2 sensilla at
apex, 1 of them larger; galeae differentiated (10 x
25 pm). Labium (w = 180 pm) with 2 setae (1 = 12
pm) behind palpi; labial palpus (14 x 12 pm) with
4 sensilla at apex, one of them larger; salivary or-
ifice (Fig. 13c) as a transverse slit (w = 85 pm).


Chrysura hybrida (Lepeletier, 1806),
(Figs. 14-19, 21-26)

General Aspect (Fig. 14): Body robust (1 = 0.8
cm, w = 0.3 cm); abdominal segments divided into
2 annulets by a transverse crease. Anus terminal,
as a transverse slit. Pleural lobes (Figs. 20, 21) de-
veloped, with a seta on apex. Integument (Figs.
21, 22) with setae on each segment, arranged in a
transversal row (1 = 3-4 pm). Spiracles (Figs. 15,
23): (d first pair = 60 pm, rest = 43-58 pm, x (rest)
= 51.9 pm, n = 12) with peritreme; atrium simple,
naked. Cranium with sparse setae (1 = 8 pm).
Coronal suture scarcely developed, parietal bands
absent. Antennal orbits (Fig. 16) (d =16 pm) circu-
lar, with 3 sensilla at centre. Clypeus (Fig. 24a)
differentiated, with 22 setae (1 = 7 pm) regularly
distributed. Labrum (Figs. 17a, 23, 24b) (w = 350
pm; h = 120 pm) emarginate, with around 28 se-
tae (1= 7 pm). Epipharynx (Fig. 17b) with 6 sen-
silla. Mouthparts: Mandible (Fig. 18) (1 = 260 pm,
w = 140 pm) tridentate. Maxilla (Fig. 19a) (w =
120 pm) with setae (1 = 14 pm) on external part.
Maxillary palpus (Fig. 25) (20 x 40 pm) with 4







Florida Entomologist 92(1)


6
0.25 cm


7
0.1 mm


r p
*

A


b a
8 9
0.2 mm 0.01 mm


Figs. 6-9, Mature larva of Chrysidea disclusa: (6) general aspect: lateral view; (7) 2nd left spiracle (atrium, sub-
atrium, and tracheal trunk); (8) cranium (frontal view); (9a) labrum and tegumental differentiations of the clypeus.
In this illustration the setae and sensilla of the clypeus are shown surrounded by a circle; (9b) epipharynx.


sensilla at apex; galeae (10 x 10 pm). Labium (Fig.
19b) (h = 280 pm, w = 160 pm) with 4 setae (1 = 12
pm) behind palpi; labial palpus (Fig. 26) (40 x 40
pm) with 4 sensilla at apex; salivary orifice (Figs.
23, 24c) as a transverse slit (w = 90 pm).
Smicromyrme rufipes (Fabricius, 1787),
(Fig. 20)

The description agrees with that offered by
Grandi (1961), to which the following aspects
should be added:
General Aspect: Integument with scattered
spinules (1 of spinules = 12 pm) and setae (1 = 20-30
pm). Abdominal and metathoracic spiracles with
the atrium lined with ridges; opening into sub-
atrium large and unarmed; subatrium long and ex-
panded (d = 80 pm), with 6 swellings (Fig. 20).

DISCUSSION

The larval morphology of the European species
belonging to the genus Bembix has been studied


by Asis et al. (1989, 1992, 1997) and Grandi
(1926a, b; 1928). On the basis of the body chaeto-
taxy, Asis et al. (1997) separated the 8 European
species of this genus, of which the mature larvae
were known, into 2 fairly well defined groups: (1)
a first group characterized by showing well-devel-
oped setae (1 > 65 pm) and numerous spinules on
the integument (Bembix flavescens bolivari Han-
dlirsch, 1893, B. oculata Panzer, 1801, and B. ros-
trata (Linnaeus, 1758)), and (2) a second group in
which the setae of the integument are much
smaller (<40 pm) and the spinules are either ab-
sent or very scanty (Bembix merceti Parker, 1929,
B. olivacea Fabricius, 1778, B. sinuata Panzer,
1804, B. tarsata Latreille, 1809, and B. zonata
Klug, 1835). This second group would include B.
bidentata, the species described here.
Regarding other character states that could be
used in the separation of the mature larvae of Eu-
ropean species of Bembix (Asis et al. 1992; 1997),
it should be mentioned that in the larvae ofB. bi-
dentata described here a certain variability was
observed in the number of teeth on the mandibles,


March 2009







Tormos et al.: Mature Larvae of Bembix bidentata and its Parasitoids


Figs. 10-13, Mature larva of Chrysidea disclusa: (10) general aspect: ventral view; (11) 1st left spiracle; (12) 2nd
left spiracle (detail); (13) head (frontal view) showing the antennal papilla (a), labrum emarginate (b), and salivary
orifice (c).


and the number of cupuliform sensilla on the
margin of the labrum. In contrast, the ratio
length of the antennal papilla: width of the anten-
nal orbit is constant (without variability). Despite
this, since only 2 mature larvae were studied, it
would be advisable to study a greater number of
specimens of this and other species of the genus to
determine whether this character state can be
used to differentiate the final larval instar of Be-
mbix species.


The biology of the Chrysididae is poorly known.
Most information refers only to host identity, and
even this is scanty (Evans 1966; Krombein 1967;
Kimsey & Bohart 1990). It is therefore not surpris-
ing that to date all known hosts of C'i, ....'. have
been bees of the family Megachilidae (Hicks 1934;
Kimsey & Bohart 1990). Here, we expand the range
of hosts into the Crabronidae.
The description of the mature larvae of 2 Chry-
sidini (1 of them belonging to a genus whose final







Florida Entomologist 92(1)


20
0.05 mm


15
0.05 mm


18
0.1 mm


0.5 cm


19
0.1 mm


Figs. 14-20. Mature larva of Chrysura hybrida: (14) general aspect; (15) 2nd left spiracle (atrium, subatrium, and tra-
cheal trunk); (16) antennal orbit; (17a) labrum; (17b) epipharynx; (18) mandible; (19a) maxilla; (19b) labium.; Mature
larva of Smicromyrme rufipes: (20) abdominal spiracle (atrium, subatrium, and tracheal trunk).


larval stage morphology was unknown), provides
new information that underscores the importance
of larval characters when establishing the phylo-
genetic relationships of the Chrysididae.


The mature larvae ofC. disclusa and Ch. hybr-
ida share the character states that define the last
instar of Chrysididae, Chrysidinae, and Chrysi-
dini. The family Chrysididae is defined by dis-


j
f
C

~ Pt


March 2009






Tormos et al.: Mature Larvae of Bembix bidentata and its Parasitoids










20.0'L kV40 20 G E1.


Figs. 21-23. Mature larva of Chrysura hybrida: (21) swelling showing a seta on apex; (22) setae of the integu-
ment; (23) 1st left spiracle (detail);.


playing the labrum with sensilla, and a well de-
veloped peritreme. The subfamily Chrysidinae
can be characterized by the following autapomor-
phies: (1) an integument with setae, and (2) a la-
brum with more than 2 setae. The mature larvae
of the tribe Chrysidini are defined by showing ab-
dominal segments divided into 2 annulets, and
having cranium with 5 or more pairs of setae.
Following the analysis in the larvae already
studied of the 15 characters that seem to be im-
portant to clarify the phylogeny of the group (Tor-
mos et al. 2001; 2006), we observe that there are


no autapomorphies within the Chrysidini that
characterize the genus C'i l./... (Table 1). Ac-
cordingly, this taxon can be characterized by a
combination of the 2 characters (Table 1), as fol-
lows: (1) an atrium without asperities or weak
lines on the circumference (a character state
shared with the genera Chrysis Linnaeus, Chry-
sura, Stilbum Spinola, and Trichrysis Lich-
testein), and (2) antennal papillae longer than
broader (a character state shared with the genus
Caenochrysis Kimsey & Bohart). C'/i ......-. hybr-
ida is characterized, within its genus, by display-







Florida Entomologist 92(1)


Figs. 24-26. Mature larva of Chrysura hybrida: (24) clypeus (a) showing the setae (see arrow), and detail of la-
brum (b) and salivary orifice (c); maxillary palpus (25) and lapial palpus (26) showing the sensilla on apex.


ing the autapomorphy maxillaryy palpus with 4
sensilla at apex" (Table 1).
Bearing in mind the character states provided
in this study, the mature larva ofS. rufipes, unlike
other species of Smicromyrmini described, exhib-
its the followings traits (Table 2): (1) head without
parietal bands, (2) frontoclypeal suture distinct,
and (3) labium with more than 8 apical setae, and
without apical papillae. Although there is no au-
toapomorphy that allows the mature larva of
Smicromyrme Thomson to be characterized,
within the set of the family Mutillidae, it may be
affirmed that the mature larva of this genus is


characterized within the Mutillinae, by display-
ing more than 8 apical setae and no apical papil-
lae on labium.


ACKNOWLEDGMENTS

We are indebted to Franco Strumia (Museo di Storia
Natural e del Territorio, Pisa, Italy) and Guido Pa-
gliano (Museo Regionale Scienze Naturali, Torino, It-
aly) for helping in the determination of the chrysidid
and mutillid parasitoids, respectively. Grants from the
DGES (CGL2006-02568) and Junta de Castilla y Le6n
(SA010AO6) supported the study.


March 2009








Tormos et al.: Mature Larvae of Bembix bidentata and its Parasitoids


TABLE 1. CHARACTERS USED IN THE TYPIFICATION OF THE MATURE LARVAE OF CHRYSIDIDAE. -ABDOMINAL SEGMENTS:
(1) ALL DIVIDED INTO 2 ANNULETS (+); NOT ALL DIVIDED INTO 2 ANNULETS (-). -INTEGUMENT: (2) WITH SE-
TAE (+); WITHOUT SETAE (-). (3) WITH SPINES (+); WITHOUT SPINES (-); SPIRACLES: (4) ATRIUM WITH AS-
PERITIES OR WEAK LINES ON CIRCUMFERENCE (+); ATRIUM WITHOUT ASPERITIES OR WEAK LINES ON
CIRCUMFERENCE (-). (5) OPENING INTO SUBATRIUM WITH SPINES (+); OPENING INTO SUBATRIUM WITHOUT
SPINES (-). CRANIUM: (6) WITH 5 OR MORE PAIRS OF SETAE (+); WITH 1 TO 4 PAIRS OF SETAE (-); WITHOUT
SETAE (*). ANTENNAL PAPILLAE: (7) LONGER THAN BROADER (+); AS LONG AS BROAD OR BROADER THAN LONG
(-). (8) WITH 3 SENSILLA AT APEX (+); WITH 2 SENSILLA (-); WITH 4 SENSILLA (*). LABRUM: (9) EMARGIN-
ATED (+); NOT EMARGINATED (-). (10) WITH SENSILLA (+); WITHOUT SENSILLA (-). MANDIBLES: (11) WITH
SETAE ON THE BASE (+); WITHOUT SETAE ON THE BASE (-). MAXILLAE: (12) WITH SPINULES (+); WITHOUT
SPINULES (-). MAXILLARY PALPI: (13) WITH 5 SENSILLA AT APEX (+); WITH A DIFFERENT NUMBER OF SEN-
SILLA (-). GALEAE: (14) HIGHLY DEVELOPED (>78 pIM x 57 lIM) (+); NORMALLY DEVELOPED (7-29 lIM x 9-39
JIM) (-); POORLY DEVELOPED (3-10 lIM x 3-10 pIM) (*); ABSENT (&). LABIUM: (15) WITH MARGIN PAPILLOSE
(+); NOT PAPILLOSE (-).

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15


CHRYSIDIDAE, CHRYSIDINAE, CHRYSIDINI
Caenochrysis doriae (Gribodo) +
C. mucronata (Brull6) +
C. sayi Bohart +
Chrysidea disclusa (Linsenmaier) +
Chrysis angustula Schenk +
C. cembricola Krombein +
C. cessata Buysson +
C. fulgida Linnaeus +
C. gracillima Forster +
C. inaequidens Dahlbom +
C. inflata Aaron +
C. nitidula Fabricius +
C. smaragdula Fabricius +
Chrysura hybrida (Lepeletier) +
C. pacifica (Say) +
C. sonorensis (Cameron) +
Exochrysis tolteca (Mocsary) +
Stilbum cyanura (Forster) +
Trychrysis cyanea (Linnaeus) +

CHRYSIDIDAE, CHRYSIDINAE, ELAMPINI
Hedychridium elegantulum Buysson
H. solierellae Bohart & Brumley
Philoctetes intermedius (Aaron)
Omalus biaccinctus (Buysson)
0. aeneus (Fabricius) -
Pseudolopyga taylori (Bodenstein)


+-+ + + +
+ -++ ++ +
+ -++ ++ +
+ ++ +
+ -++ +
+-+ +
+ -++ +
+ -++ +
+-+ +
+ -++ +
+ -++ +
+ -++ +
+ -++ +


++


CHRYSIDIDAE, AMISEGINAE
Adelphe anisomorphae Krombein
Myrmecomimesis bispinosus (Riek)


+ +
+ +


+ +/- +/-


+ &



+ +

+-



+-


+ +


-(3) *
-(3) *


BETHYLIDAE


+/- + &







Florida Entomologist 92(1)


March 2009


I + + + .+ I .







S+ +++++++


+ +


++I I +






+ |+ | | + |+ |







Tormos et al.: Mature Larvae of Bembix bidentata and its Parasitoids


REFERENCES CITED

ASiS J. D., GAYUBO, S. F., AND TORMOS, J. 1989. Notes
on the preimaginal states of Iberian Sphecidae (IV).
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Handlirsch, 1893 and Bembix sinuata Panzer, 1804
(Hymenoptera, Sphecidae). Nouv. Revue. Ent. (N.S.)
6: 313-319.
ASis J. D., GAYUBO, S. F., AND TORMOS, J. 1992. Data on
the nesting behaviour of five European Bembix and
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N. F. 39: 221-231.
ASIS J. D., GAYUBO, S. F., AND TORMOS, J. 1997. De-
scripci6n de las larvas maduras de Hoplisoides punc-
tuosus (Eversmann) y Bembix zonata Klug. Doriana
VI (299): 1-8.
BROTHERS D. J., TSCHUCH, G., AND BURGER, F. 2000.
Associations of mutillid wasps (Hymenoptera,
Mutillidae) with eusocial insects. Insect. Soc. 47:
201-211.
EVANS, H. E. 1959. Studies on the larvae of digger
wasps (Hymenoptera, Sphecidae). Part V: Conclu-
sion. Trans. American Entomol. Soc. 85: 137-191.
EVANS, H. E. 1964. Further studies on the larvae of dig-
ger wasps. Trans. American Entomol. Soc. 90: 235-
299.
EVANS, H. E. 1966. The Comparative Ethology and Evo-
lution of the Sand Wasps. Cambridge, Mass.: Har-
vard University Press.
EVANS, H. E. 1987. Order Hymenoptera, pp. 597-710 In
F. W. Stehr [ed.], Immature Insects. Vol. 2. Dubuque,
Iowa: Kendall/Hunt, Publishing Company.
EVANS, H. E., AND LIN, C. S. 1956. Studies on the larvae
of digger wasps (Hymenoptera: Sphecidae). Part II:
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GRANDI, G. 1926a. Contributi a la conoscenza della bio-
logia e della morfologia degli imenotteri melliferi e
predatori III. Bol. Lab. Zool. Gen. 19: 269-327.
GRANDI, G. 1926b. Contributi a la conoscenza della bio-
logia e della morfologia degli imenotteri melliferi e
predatori IV. Mem. Soc. ent. Ital. 5: 187-213.
GRANDI, G. 1928. Contributi a la conoscenza biological e
morfologica degli imenotteri melliferi e predatori VI.
Bol. Lab. Entom. R. Ist. sup. agr., 1: 8-31.


GRANDI, G. 1961. Studi di un entomologo sugli Imenot-
teri Superiori. Boll. Ist. Ent. Univ. Bologna 25: i-xvi,
397-400.
HICKS, C. H. 1934. Observations on a chrysidid parasite
and its host. Entomol. News 44: 206-209.
IIDA, T. 1979. Contributions to the knowledge on the
sphecid larvae in Japan (Hymenoptera). Part II.
Kontyu 37: 280-289.
KIMSEY, L. S., AND BOHART, R. 1990. The Chrysidid
Wasps of the World. New York: Oxford University
Press.
KROMBEIN, K.V. 1967. Trap-Nesting Wasps and Bees:
Life Histories, Nests, and Associates. Washington
D.C.: Smithsonian Press.
MELO, G. A. R. 1999. Phylogenetic relationships and
classification of the major lineages of Apoidea (Hy-
menoptera), with emphasis on the crabronid wasps.
Scientific Papers, Nat. Hist. Mus. Univ. Kansas 14:
1-55.
PITTS J. P., AND MATTHEWS, R. W. 2000. Description of
the larva of Sphaeropthalma pensylvanica_(Lepele-
tier) (Hymenoptera: Mutillidae: Sphaeropthalmi-
nae). J. Entomol. Sci. 35: 334-337.
PULAWSKI, W. J. 2007. Catalog of Sphecidae. http://
www.calacademy.org/research/entomology/
Entomology_Resources/Hymenoptera/sphecidae/
Genera_and_species_PDF/introduction.htm.
TORMOS, J., KROMBEIN, K. V., Asis, J. D., AND GAYUBO,
S. F. 2001. A Systematic Study of Larvae of Chrysi-
dini (Hymenoptera: Chrysididae). Ann. Entomol.
Soc. America 94(6): 809-834.
TORMOS, J., ASIS, J. D., AND GAYUBO, S. F. 2003. De-
scription of the Mature Larva of Nemka viduata
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Crabronidae: Bembicinae). J. Entomol. Sci. 38(4):
502-510.
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2006. Description of the postdefecating larva of Stil-
bum cyanura (Forster) and observations on adult be-
havior. J. Entomol. Sci. 41(1): 1-8.
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idae). J. Entomol Sci. 42(1): 52-55.







Florida Entomologist 92(1)


March 2009


BIOLOGY OF STETHOCONUS PRAEFECTUS (DISTANT) (HETEROPTERA:
MIRIDAE), A NEWLY ESTABLISHED PREDATOR OF THE AVOCADO LACE
BUG, PSEUDACYSTA PERSEAE (HETEROPTERA: TINGIDAE), IN FLORIDA


C. M. HOLGUIN', J. E. PENA', T. J. HENRY2 AND F. ACEVEDO1
1University of Florida, Department of Entomology and Nematology, Tropical Research and Education Center,
18905 SW 280th Street, Homestead, FL 33031
E-mail: jepena@ufl.edu

2Systematic Entomology Laboratory, Agricultural Research Service, United States Department of Agriculture,
c/o National Museum of Natural History, Smithsonian Institution, MRC-168, Washington, D. C. 20013-7012
E-mail: thenry@ars.usda.gov


ABSTRACT

The Asian plant bug Stethoconus praefectus (Distant) (Heteroptera: Miridae) was recently
discovered in Florida preying on the avocado lace bug, Pseudacysta perseae (Heidemann)
(Heteroptera: Tingidae). Its life cycle and effectiveness as a predator of P. perseae were in-
vestigated at 26 1 C, 60 5 RH, and 12: 12 (L: D) under laboratory conditions. Stethoconus
praefectus developed from egg to adult in 16.5 0.2 d. On average, the first 4 instars con-
sumed 2 to 4 prey per day, whereas the last 2 instars consumed 2 to 7 lace bugs per day. Ste-
thoconus praefectus was observed in the field from Aug through Dec 2007.

RESUME

Se descubri6 recientemente en Florida a Stethoconus praefectus (Distant) (Heteroptera: Mi-
ridae) depredando el chinche de encaje del aguacate, Pseudacysta perseae (Heidemann) (He-
teroptera: Tingidae). Se investigaron bajo condiciones de laboratorio tanto el ciclo biol6gica
como su efectividad como depredator de P. perseae. El desarrollo de S. praefectus desde huevo
hasta adulto duro 16.5 0.2 dias a 26 1 C, 60 + 5 HR, y 12: 12 de horas luz. Los primeros
cuatro instares consumieron 2 a 4 press por dia mientras que los ultimos dos instares con-
sumieron un promedio de dos a 7 chinches de encaje por dia. Stethoconus praefectus se en-
contr6 en el cmapo desde el mes de Agosto, hasta diciembre, 2007.

Translation by the authors.


The avocado lace bug, Pseudacysta perseae
(Heteroptera: Tingidae), is a secondary pest of av-
ocado and other Lauraceae in Florida, and other
states within the continental United States (Peia
et al.1998; Wysoki et al. 2002; Hoddle et al. 2005),
and in the Caribbean and northern South Amer-
ica (Streito & Morival 2005; Etienne & Streito
2008). Due to a resurgence of P perseae densities
in the 1990s, a survey for natural enemies was
conducted in 1997 (Peia et al. 1998). During this
survey, C'i (h ..'..' rufilabris (Burmeister) (Neu-
roptera: Chrysopidae) and Paracarniella cubana
(Bruner) (erroneously identified then as Hy-
aliodes vitripennis (Say)) (Heteroptera: Miridae)
were observed as the most common predators ofP.
perseae in south Florida (Pefa et al. 1998). In
2006, two additional predators were discovered, a
new lestodiplosine midge (Diptera: Cecidomyi-
idae), Tingidoletes praelonga (Gagne et al. 2008),
and an adventive Asian plant bug, Stethoconus
praefectus (Distant) (Heteroptera: Miridae)
(Henry et al. in press), the latter of which is
treated in this paper.


Species of Stethoconus are considered obligate
lace bug predators (Mathen & Kurian 1972;
Henry et al. 1986; Neal et al. 1991; Wheeler
2001). For example, S. japonicus Schumacher
preys on the lace bug Stephanitis pyriodes (Scott)
(Neal et al. 1991), S. pyri (Mella) (as S. cryptopel-
tis Flor) preys on Tingis pyri Fabricius (Gautier
1927), and S. praefectus has been recorded prey-
ing on the coconut lace bug, Stephanitis typicus,
in India (Mathen & Kurian 1972). The life history
of S. praefectus feeding on S. typicus was studied
by Mathen & Kurian (1972). The potential impor-
tance of S. praefectus in Florida prompted us to
investigate its life cycle and efficacy as a predator
of P perseae.

MATERIALS AND METHODS

A laboratory colony of S. praefectus was es-
tablished with adults collected from avocado
plants in a greenhouse located at the University
of Florida, Tropical Research and Education
Center (TREC), Homestead, FL (25E30' N,







Holguin et al.: Biology of Avocado Lace Bug Predator


80E30', 1 m altitude). The conditions of the
rearing and laboratory experiments were 26 +
1C, 60 + 5 RH, and 12:12 (L:D). Adults and
nymphs of P. perseae and nymphs of S. praefec-
tus were transferred into clear Plexiglass
cages (30 x 30 x 30 cm) with avocado leaves held
in a vial of water as a food source and as an ovi-
position substrate. Every other day, sections of
leaves containing newly deposited S. prafectus
eggs were removed and placed in large petri
dishes (5 x 1.5 cm) lined with a disk of paper fil-
ter and an avocado leaf. Newly emerged
nymphs of S. praefectus were transferred to in-
dividual petri dishes, containing sections of an
avocado leaf. Approximately 10 each of P. per-
seae nymphs and adults were introduced on the
petri dish as food. Every 2 d, leaves and dead
lace bugs were removed and replaced until S.
praefectus adults emerged.

Development Time of S. praefectus and Efficacy of
Nymphs as Predators

Stethoconus praefectus adults (females and
males) that were 1 d old were confined in clear
Plexiglass cages and provided with avocado lace
bugs as described above. After 24 h, S. praefectus
adults were removed and 32 eggs were chosen
randomly and labeled. Avocado leaf sections con-
taining S. praefectus eggs were placed in petri
dishes (3 x 1 cm) layered with a filter paper and
observed until eclosion. Once eggs hatched,
newly emerged nymphs were placed in small, in-
dividual petri dishes (3 x 1 cm), with a layer of
agar (1.2 g of agar in 100 mL of water) covering
the bottom, topped with a circular section of an
avocado leaf, and sealed with punctured Cling-
wrap. A total of 10 adults and nymphs of the
avocado lace bug were provided daily as food.
The petri dish was turned upside down to simu-
late the natural P. perseae feeding conditions on
the abaxial leaf side. Dead P perseae were
counted and removed daily and the development
of S. praefectus was recorded. Fresh sections of
avocado leaves were renewed every 2-3 d follow-
ing the same procedure as described above. De-
velopmental time from egg to adult, sex ratio,
and avocado lace bugs eaten per instar were re-
corded. The experiment was replicated 32 times.
Data were analyzed by one-way ANOVA for un-
equal replication by the Student-Newman-Keuls
Test (SAS Institute 1999). Data are expressed as
mean standard error.

Predator Efficacy of S. praefectus Adults

Newly emerged S. praefectus adults were iso-
lated for 24 h on avocado leaves with lace bugs in
a clear Plexiglass cage. After sex determination,
males and females were placed in petri dishes
with a disk of filter paper covering the bottom and


topped with a section of an avocado leaf as de-
scribed above. Mixed instars of avocado lace bugs
(n = 15) were provided as food. Every other day,
dead lace bugs were counted and removed until
all S. praefectus adults died. The results were an-
alyzed by a t-test for 2 groups with Proc. TTEST
(SAS Institute 1999). Data are expressed as mean
standard error.

Densities of S. praefectus in Florida

Twenty avocado leaves with symptoms of P.
perseae feeding were collected monthly (May-Dec
2007) from the avocado orchard of the USDA,
ARS, Subtropical Horticulture Research Station,
Miami, Florida (25E38'40.69"N, 80E17'50.47").
Leaves were placed in a cooler and brought to the
laboratory and inspected for the presence of P.
persea, as well as eggs, nymphs, or adults of any
predators. Egg predators were placed in 5-mL
sealed vials as described above. Nymphs were
identified to species.

RESULTS AND DISCUSSION

Developmental Time

Eggs of S. praefectus are inserted individually
on the mid and lateral veins on the adaxial sur-
face of avocado leaves (Henry et al. 2009). Eggs
hatched within 7.2 0.1 d. There were from 5 to 6
instars for both sexes. The development time for
S. praefectus from egg to adult for the 5-instar
group was 14.3 tol5.8 d for females and males, re-
spectively, and 17.6 to 19.4 d for the 6-instar
group (Table 1).
The duration of the life cycle when S. praefec-
tus fed on P. perseae was similar to that of this
lace bug when it fed on Stephanitis typicus (Ma-
then & Kurian 1972). The only major difference
between the two studies is that we observed 5 to
6 instars, whereas Mathen & Kurian (1972) ob-
served only 5. Variation in number of instars in
Heteroptera has been found for other predacious
mirids (Liquido & Nishida 1985), as well as for
phytophagous species (Slansky & Rodriguez
1987).

Predator Efficacy of S. praefectus Nymphs

Predation by S. praefectus nymphs increased
from the first to the last instar. Last instars (ei-
ther fifth or sixth) killed significantly more P per-
seae nymphs and adults than any preceding in-
star (F = 12.70; df 5, 291, P = 0.05). On average,
the first 4 instars consumed 2 to 4 prey per d,
whereas the last 2 instars consumed 2 to 7 lace
bugs per d (Table 2). These results differ from
those of Mathen & Kurian (1972), who found that
fewer prey were consumed by the fifth instar.







Florida Entomologist 92(1)


TABLE 1. DEVELOPMENT TIME (MEAN SE) FOR S. PRAEFECTUS (DAYS).

F M Combined
Instar (n) (n) (n)

Egg 7.2 0.14 (16) 7.3 0.18 (16) 7.2 0.11 (32)
N1 1.9 0.06 (16) 2.1 0.06 (16) 2.0 0.05 (32)
N2 1.2 0.11 (16) 1.2 0.10 (16) 1.2 0.07 (32)
N3 1.4 0.13 (16) 1.4 0.13 (16) 1.4 0.09 (32)
N4 1.4 0.13 (16) 1.3 0.12 (16) 1.4 0.09 (32)
N5 2.6 0.22 (16) 2.5 0.18 (16) 2.5 0.14 (32)
N6 3.7 0.75 (4) 1.8 0.40 (6) 2.6 0.05 (10)
Total 16.7 0.25 16.5 0.26 16.5 0.18


TABLE 2. DAILY CONSUMPTION BY EACH INSTAR OF S. PRAEFECTUS AND NATURAL MORTALITY (MEAN SE).

Day

Instar n 1 2 3 4 5 6 Total mean

N1 32 1.9 0.15 1.3 0.142 3.0* 3.0 0.23
N2 32 1.1 0.17 1.8 0.260 1.7 0.18
N3 32 1.8 0.22 4.0 0.340 3.4 0.38
N4 32 2.1 0.25 4.1 0.693 3.0* 3.8 0.51
N5 32 4.9 0.53 2.1 0.334 3.4 0.42 2.0 2.0 6.0* 7.8 0.83
N6 10 4.8 0.83 1.8 0.595 3.2 0.66 7.0 0.0 0 0 7.5 1.82
Control 30 0.6 0.09

*No Standard error.


Longevity and Predator Efficacy of S. praefectus Adults

Adult females ofS. praefectus lived longer and
consumed more prey than adult males (Table 3).
According to Neal et al. (1991) and Mathen &
Kurian (1972), the total number of prey killed by
adults of the genus Stethoconus is higher be-
cause adulthood lasts longer than immature
stages.

Densities of S. praefectus Under Field Conditions

The number of P perseae increased from Jul
through Sep and decreased during the fall of 2007
(Fig. 1). Stethoconus praefectus was not observed
until Aug and the population peaked in Oct
(Fig. 1). Our results indicate that S. praefectus is


an important predator of P perseae and, together
with other predators, could cause significant cu-
mulative mortality. For instance the chrysopid C.
rufilabris causes a cumulative mortality of 75% of
P perseae, preferring nymphs over eggs and
adults (Peia et al. 1998); the plant bug Paracarn-
iella cubana feeds on eggs and nymphs, causing a
30% reduction of P perseae during a 4-day obser-
vation period (Peia, unpublished data). No data
are available on the effectiveness of the other
newly discovered predator, the cecidomyiid Tingi-
doletes praelonga (Gagne et al.2008), but it likely
contributes to the overall mortality of P perseae.
As a consequence, S. praefectus, together with
other predators present in the area, might be re-
sponsible for keeping densities of P perseae at low
levels in Florida compared with other localities,


TABLE 3. LONGEVITY (DAYS) AND PREDATOR EFFICACY OF S. PRAEFECTUS MALES AND FEMALES, AND NATURAL MOR-
TALITY OF P. PERSEA IN THE ABSENCE OF S. PRAEFECTUS (MEAN SE).

Longevity Consumption
Treatment n Mean Range Total

Female 12 12.2 2.53 a 55 10.77 a
1-30
Male 10 5.7 0.76 b 30.4 3.78 b
1-9
Control 0.9 0.25


March 2009








Holguin et al.: Biology of Avocado Lace Bug Predator


50


40


30








0
2 O



z
1 4


May June July Aug Sept
2007


Oct. Nov. Dec.


Fig 1. Pseudacysta perseae and predators found per
avocado leaf at the USDA, Miami, Florida (mean SE)
(May-Dec 2007).



such as Puerto Rico and the Dominican Republic
(Etienne & Streito 2008) where the apparent lack
of natural enemies makes P perseae a serious
problem.

ACKNOWLEDGMENTS

We thank Nancy Epsky (USDA, ARS, Miami), Josep
Jacas (Univerisa Jaume I, Castell, Spain), Michael G.
Pogue (Systematic Entomology Laboratory [SEL],
USDA, ARS, Washington, DC), F. Christian Thompson
(SEL), and Alfred G. Wheeler, Jr. (Clemson University,
Clemson, SC) for critically reviewing this manuscript,
and David Long (University of Florida, Homestead) for
help with fieldwork and laboratory rearing. This re-
search was partially supported by a grant from the Cal-
ifornia Department of Agriculture to JEP

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ocatier (Hemiptera: Tingidae). Bull. Soc. Entomol.
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GAGNE, R. J., PENA, J. E., AND ACEVEDO, F. 2008. A new
lestodiplisine (Diptera: Cecidomyiidae) preying on


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GAUTIER, C.1927. A propos de Stethoconus cyrtopeltis
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in the United States, promising in the biocontrol of
azalea lace bug (Heteroptera: Tingidae). Proc. Ento-
mol. Soc. Washington 88: 722-730.
HENRY, T. J., PENA, J. E., LONG, D., AND ACEVEDO, F.
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mol. Soc. America 78: 459-463.
MATHEN, K. AND KURIAN, C. 1972. Description, life-
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Stephanitis typicus (Distant) (Heteroptera:
Tingidae), a pest of coconut palm. Indian J. Agric.
Sci. 42: 255-262.
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adventive predator of the azalea lace bug (Het-
eroptera: Tingidae). Ann. Entomol. Soc. Am. 84(3):
287-293.
PENA, J. E., SUNDHARI, S., HUNSBERGER, A., AND DUN-
CAN, R. 1998. Monitoring, damage, natural enemies
and control of avocado lace bug, Pseudacysta perseae
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SAS INSTITUTE. 1999. SAS version 9.1. SAS Institute,
Cary, NC.
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tebrates. John Wiley and Sons, New York. 1016 pp.
STREITO, J. C., AND MORIVAL, Y. 2005. Premiere capture
en Guyane francaise de Pseudacysta perseae (Heide-
mann, 1908) un ravageur de l'avocatier (Het-
eroptera: Tingidae). Nouv. Rev. Entomol. 22: 191-
192.
WHEELER, A. G., Jr. 2001. Biology of the Plant Bugs
(Hemiptera: Miridae). Pests, Predators, Opportun-
ists. Cornell University Press, Ithaca, New York. 507
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WYSOKI, M., VAN DE BERG, M. A., ISH-AM, G., GAZIT, G.,
PENA, J. E., AND G. WAITE, G. K. 2002. Pests and pol-
linators of avocado, pp. 223-293 In J. E. Peia, J. L.
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UK. 430 pp.


I Chuysoperla
m Tinniolet~s
--l Pralcm, ieI lla







Florida Entomologist 92(1)


March 2009


FECUNDITY OF LARRA BICOLOR (HYMENOPTERA: CRABRONIDAE) AND
ITS IMPLICATIONS IN PARASITOID: HOST INTERACTION WITH MOLE
CRICKETS (ORTHOPTERA: GRYLLOTALPIDAE: SCAPTERISCUS)


S. L. PORTMAN1, J. H. FRANK2, R. MCSORLEY2 AND N. C. LEPPLA2
1Dept. of Biology, 410 Mueller Laboratory, Penn State University, University Park, PA 16802

2Entomology & Nematology Department, University of Florida, Gainesville, FL 32611-0630

ABSTRACT

Larra bicolor F. (Hymenoptera: Crabronidae) is a specialist parasitoid of Scapteriscus (Or-
thoptera: Gryllotalpidae) mole crickets, attacking adults and medium to large nymphs. Re-
productive systems were dissected from 10 female wasps collected in northern Florida. Each
had 2 ovaries, each with 3 ovarioles. The maximal number of mature eggs (10) plus devel-
oping oocytes (83) was 93. Female wasps deposit an egg on the venter of the host's thorax,
and the wasp larva develops as an ectoparasitoid. Twenty newly-emerged female wasps
housed in small cages with at least 1 male and with 7 potential hosts replaced daily depos-
ited a mean 2.44 eggs (range 0-10) per day for a total lifetime production averaging 56 eggs
(range 17-91) during a lifespan averaging 23.5 d (range 8-40). Assuming 3 wasp generations
with fecundity as shown to 1 host generation, per year, the wasp should easily be able to out-
reproduce its host mole crickets. A few of the hosts became superparasitized with 2 or even
3 eggs, but at most 1 larva of L. bicolor developed successfully on each host, so superpara-
sitism is a disadvantage; its incidence in the laboratory (<2%) and field (3%) was low.

Key Words: reproduction, ovarian structure, superparasitism, fertility

RESUME

La avispa Larra bicolor F. (Hymenoptera: Crabronidae) es un parasitoide especializado en
grillotopos del g6nero Scapteriscus (Orthoptera: Gryllotalpidae) que ataca a adults y ninfas
de tamanos medio y grande. Se diseccionaron los sistemas reproductivos de 10 hembras co-
lectadas en el norte de Florida. Cada uno tenia dos ovarios con tres ovarioles. El numero
maximo de huevos maduros (10), mas los oocitos en desarrollo (83), fue 93. Las hembras de-
positan un huevo sobre la superficie ventral del t6rax del hospedero, y la larva de la avispa
se desarrolla externamente como ectoparasito. Viente hembras recientemente eclosionadas
y mantenidas en jaulas pequenas, junto con por lo menos un macho y siete hospederos po-
tenciales reemplazados diariamente, ovipositaron un promedio de 2.44 huevos (rango 0-10)
por dia para una producci6n total de un promedio de 56 huevos (rango 17-91) durante una
vida de promedio de 23.5 dias (rango 8-40). En tres generaciones de la avispa, con la fecun-
didad potential demostrada y contra una sola generaci6n de grillotopos, esta avispa podria
producer mas descendencia que su hospedero. Pocos de los hospederos fueron superparasiti-
zados con dos, o raramente tres, huevos. Al maximo solamente una larva de L. bicolor se de-
sarroll6 exitosamente en cada grillotopo, asi que el superparasitismo es un detrimento para
la avispa. La incidencia de superparasitismo en el laboratorio (<2%) y el campo (3%) fue
baja.


Translation provided by the authors.


Larra spp. have traditionally been called
wasps although they are bee-relatives (Hy-
menoptera: Apoidea). Formerly classified in
Sphecidae, they are now considered to belong to
Crabronidae in accord with online information by
W. J. Pulawski (O'Neill 2008). All are parasitoids
of mole crickets (Orthoptera: Gryllotalpidae)
(Menke 1992). Larra females differ from typical
crabronids in that the paralysis they inflict on
their hosts is temporary, and larvae develop ex-
ternally on active hosts (Steiner 1984). Larra bi-
color F. is a widely-distributed South American


species using various species of Scapteriscus mole
crickets as hosts (Menke 1992). Stock from Ama-
zonian Brazil (via Puerto Rico) was introduced in
1979 into southern Florida, and stock from Bo-
livia was introduced in 1988 into northern Florida
(Frank et al. 1995) to suppress populations of in-
vasive Scapteriscus spp. Adults of the 2 stocks can
be distinguished by density of punctuation of the
head (Menke 1992). By 2005, progeny of the Bo-
livian stock was widely distributed whereas the
Brazilian stock occupied a very restricted area in
Broward County (Frank & Walker 2006). Sup-







Portman et al.: Fecundity ofLarra bicolor


pression is occurring, but its level is not clear be-
cause the wasp has several overlapping annual
generations although the hosts have only 1, at
least in northern Florida (Frank & Walker 2006).
Furthermore, only the adults and mid-sized and
larger nymphs of the hosts are susceptible, with
invulnerable small nymphs present in summer,
and the wasp is inactive underground in the pu-
pal stage during winter (Cabrera-Mireles 2002).
Castner (1988) described the diurnal hunting
behavior by L. bicolor females (Brazilian stock),
and noted that 2 to 3 eggs per female per day were
usually produced under laboratory conditions.
Castner (1986) observed superparasitism under
artificial conditions (glass test tubes). Much more
information is necessary for calculating popula-
tion effects of the parasitoid on the host, which is
1 of our long-term objectives.
Using wasps of the Bolivian stock from Ala-
chua County, Florida, we determined the struc-
ture of the wasp's ovaries and ovarioles in order to
assess potential fecundity. We report the lifetime
egg production by caged females to examine ac-
tual fecundity. We observed the outcome of super-
parasitism and compared its magnitude in cages
and in the field.

MATERIALS AND METHODS

Ovarian Structure

In Jun and Jul 2007, 10 female L. bicolor were
collected at a field site with nectar-source plants
at 29045' N, 82017' W, north of Gainesville, Ala-
chua County, Florida. These wasps were trans-
ported to the laboratory and chilled in a refriger-
ator to anesthetize them. The last abdominal seg-
ment was grasped with forceps and pulled away
from the anterior segments bringing with it the
reproductive tract. The reproductive organs were
then placed in a small Petri dish filled with ice-
cold phosphate-buffered saline solution (PBS, pH
7.0). Ovaries were dissected and rinsed in fresh
PBS, and equilibrated overnight in small vials
with 30% glycerol in PBS. They were then moved
to neutral-red staining solution in watch glasses.
After 2 min, they were removed from the stain
and washed for 5 min in a 5-mL beaker of ice-cold
PBS. The common oviduct was removed, and right
and left ovaries were separated and temporarily
mounted on a slide in 30% glycerol/PBS. The ova-
ries were photographed with a stereomicroscope
(Leica Microsystems, Wetzlar, Germany) fitted
with an Auto-Montage digital photography sys-
tem (Syncroscopy, Frederick, MD). Images were
taken at 10x magnification and were enhanced
with Photoshop 5.5 graphics-editing software
(Adobe Systems, San Jose, CA). Auto-Montage
image-processing software was used to scale the
images. Means, standard errors, and ranges were
calculated for ovariole length, mature egg num-


ber, mature egg length, oocyte number, and larg-
est and smallest oocyte length. Correlation coeffi-
cients were computed with SAS 9.1 (SAS Insti-
tute, Cary, NC).

Lifetime Egg Production

Larvae of L. bicolor collected on mole crickets
at a field site at 29050' N, 82004' W in Bradford
County, Florida were brought to the laboratory in
autumn 2006 and allowed to pupate in 92-mL (25
dram) transparent styrene vials with moist clean
sand. The newly-emerged adult wasps were used
in this experiment in May-Jun 2007. Females
were weighed as soon as they were observed to
have emerged at daily check, and then placed into
30 x 30 x 30-cm cages, 1 wasp per cage, in a green-
house with maximum temperature regulated not
to exceed 30C. One or more newly-emerged male
L. bicolor were added to try to ensure mating. Into
each cage was placed a flowering Spermacoce ver-
ticillata L. (Rubiaceae), a favored nectar source,
in a 4-L pot together with an artificial nectary (a
small glass vial fitted with a cotton wick and con-
taining a mix of honey and 20% sucrose solution).
Wasps were noted to visit flowers and artificial
nectaries. Moist sand was placed on the floor of
each cage to a depth of 2.5 cm, and it was kept
moist by spraying twice daily with tap water.
Seven parasitoid-free, healthy adult Scap-
teriscus mole crickets were added to each cage.
The number 7 was a compromise based on Cast-
ner's (1988) observation that 2-3 eggs were laid
per female per day, consistent with (a) our intent
that the number of available hosts should exceed
the number of eggs likely to be laid, and (b) with
the number of mole crickets we had in stock. Even
so, it called for 140 fresh mole crickets daily over
a period of weeks. All 3 species occurring in Flor-
ida are hosts for the Brazilian stock L. bicolor
(Castner 1984). We used a mixture of 4 or 5 S. vici-
nus Scudder, field-collected at sites near Gaines-
ville and laboratory-maintained, and 3 or 2 S. ab-
breviatus Scudder, from a long-maintained labo-
ratory culture originating from specimens col-
lected in southeastern Florida. These mole
crickets were left in the cage for =24 h. All mole
crickets were removed from each cage after sun-
set, when L. bicolor activity had ceased, and ex-
amined for the presence ofL. bicolor eggs. By the
use of sharp-pointed forceps, every egg detected
on the surface of a mole cricket was removed from
its host and recorded. Seven mole crickets were
placed back into each cage, but mole crickets from
which eggs had been removed were not recycled
into cages until >3 d had passed. This procedure
was followed daily with the mole crickets until the
female wasp (whose presence was checked daily)
had died. The routine was followed until data
were collected for the progeny of 20 female wasps.
Means and standard errors were computed for







Florida Entomologist 92(1)


the variables of wasp weight, lifespan (days), eggs
laid per day, and total number of eggs produced.
Correlation coefficients were calculated between
paired variables with SAS 9.1 (SAS Institute,
Cary, NC).

Superparasitism

Mole crickets possessing 2 or more wasp eggs
were detected during the lifetime egg production
experiment. The number and general location of
eggs were recorded. These mole crickets were
placed individually into 92-mL (25 dram) trans-
parent styrene vials with moist clean sand. Vials
were housed in an environmental chamber
(Walker et al. 1993) at 27C, 55% RH and 16:8 h
L:D. Mole crickets were fed "FRM Cricket and
Worm Feed" (Flint River Mill, Bainbridge, GA) at
least twice per week, and water was added to the
substrate as needed. Mole cricket condition and
parasitoid development were monitored by visual
inspection through the transparent wall of the
vial, or by removing the mole cricket only when
the wasp larva could not be seen through the vial
wall.
Mole crickets were trapped in pitfalls in a pas-
ture in Bradford County (locality given above), in
Oct-Dec 2005 and Aug-Dec 2006 (Portman 2007)
in a field project to be reported elsewhere. They
were brought to the laboratory for examination,
and the presence ofL. bicolor eggs and larvae was
recorded. This provided a record of superparasit-
ism in the field.

RESULTS

Ovarian Structure

All wasps dissected had 2 ovaries, each with 3
ovarioles (Fig. 1) typical of crabronids (Ohl &
Linde 2003). There were 7.60 0.63 (mean SE,
range 4-10) mature eggs and 69.0 3.30 (range
54-83) developing oocytes. Egg length was 1.63 +
0.03 mm (range 1.50-1.80). Ovariole length corre-
lated with egg load (n = 10, r = 0.81, P < 0.004).
Egg load correlated negatively with average egg


Fig. 1. Ovary of L. bicolor stained with neutral red
and mounted in 30% glycerol. Scale line = 5.0 mm.


length (n = 10, r = -0.70, P < 0.03). The maximal
number of mature eggs (10) plus developing oo-
cytes (83) was 93, albeit in different individuals.

Lifetime Egg Production

All wasps oviposited, but we could not distin-
guish male eggs from female eggs, and we do not
know whether every female mated. The few mat-
ings observed were very brief (seconds). The num-
ber of eggs laid may be underestimated if the ovi-
positing females removed any existing eggs before
depositing a new one. Castner (1986) observed re-
moval of eggs under the unusual circumstance
that he provided only 1 potential mole cricket host
per ovipositing wasp. However, (a) the maximal
number of mature eggs deposited during 1 d was
10, which matches the maximal number of ma-
ture eggs found by dissection, and (b) the maxi-
mal lifetime egg output was 91, which is very
close to the maximal number of mature eggs plus
developing oocytes (93) found by dissection (Table
1). Thus, the 2 evaluations by differing methods
support each other. The rate of oviposition corre-
lated with the initial weight of female wasps (n =
20, r = 0.68, P = 0.006), and the total egg produc-
tion correlated with lifespan (n = 20, r = 0.80, P =
0.000).

Superparasitism

Twenty mole crickets were superparasitized,
having 2 or 3 sibling eggs (<2% of the observa-
tions). Ten of the 20 had 2 eggs attached on oppo-
site sides (L-R) of the venter of the thorax. Nine
had 2 eggs attached adjacently. One had 3 eggs, 2
adjacent and 1 opposite (Fig. 2). After hatching,
every larva attached without relocating and with-
out attacking a sibling. In no instance did more
than 1 larva per host survive to pupation, and in
10 instances (5 with the 2 eggs adjacent, and 5
with 2 eggs opposite) both larvae died. Survival to
pupation was only 24.4% overall, which contrasts
with survival of 97.6% reported for single L. bi-
color larvae (Cabrera-Mireles 2002).

DISCUSSION

Although superparasitism occurred, it was a
disadvantage. The experimental method did not
allow observation of females ovipositing, and it is
unknown whether females removed any of the
eggs they found. The strategy followed by most of
the female wasps (of the Brazilian stock) observed
by Castner (1986), of removing an existing egg be-
fore depositing a new one, would have allowed the
new egg a much greater chance of developing.
However, those females may not have been able,
after 24 h, to distinguish their own eggs from
those of other females. The simplest hypothesis
with the new observations is that female wasps


March 2009







Portman et al.: Fecundity ofLarra bicolor


TABLE 1. LIFE HISTORY TRAITS OF L. BICOLOR FEMALES. FOR EACH MEASUREMENT N = 20.

Trait Mean SEM Minimum Maximum

Wasp weight (mg) 107.43 8.71 58 185
Lifespan (d) 23.5 1.87 8 40
Lifetime egg output 56.05 4.38 17 91
Daily egg output 2.44 0.14 0 10


could recognize their own previously-deposited
eggs and chose to deposit another without remov-
ing the earlier one(s). If a female's normal behav-
ior is to move away from the proximity of a host
she has parasitized, the chance of re-encounter
with a host that she had parasitized might be re-
duced. Overall, superparasitized mole crickets
amounted to <2% of the laboratory observations.
However, the incidence of superparasitism in
mole crickets collected from pitfall traps in the
field was 3% (9 out of 304 parasitized mole crick-
ets had 2 wasp eggs whereas all others had a sin-
gle egg or single larva), so the cage experiments
were a reasonable approximation of events in the
field.
The new data on lifespan, and on daily and life-
time egg output place us a few steps closer to un-
derstanding the dynamics of L. bicolor popula-


tions in northern Florida. At 26 2C and 65 5%
RH, L. bicolor (Brazilian stock) eggs incubate for
6-7 d, the 5 instars develop in 10-11 d at the end
of which the host dies, a further day is spent con-
structing a cocoon, and the pupal duration is 6-8
weeks (Castner 1988). In an seasonal tropical
climate with continuous host availability, this
might give the capability of 4.5 generations each
year, but because of variability among individuals
in development time and because each female ovi-
posits through her adult lifespan, we would ex-
pect completely overlapping generations. There-
fore, it would not be possible to distinguish gener-
ations in the field. Effects of insect parasitoid pop-
ulations on host populations are almost always
calculated based on 1 discrete generation of para-
sitoid per host generation, so such a calculation
would not be possible.


Fig. 2. Venter of the thorax of a Scapteriscus mole cricket bearing 3 eggs deposited by 1 L. bicolor female within
1 d. All are between the 1st and 2nd pairs of legs and each is =1.6 mm long.







Florida Entomologist 92(1)


Northern Florida has a seasonal climate with
freezing temperatures in winter, and L. bicolor
adults are killed by hard frost (Cabrera-Mireles
2002). The duration of the pupal stage is highly
variable with range 45-238 d; at least some pupae
late in the autumn enter diapause, which is not
broken until the following spring, with adults
emerging throughout May in outdoor, under-
ground hearings (Cabrera-Mireles 2002). Over-
wintered pupae reared from field-collected larvae
late in autumn 2006 and placed in an environ-
mental chamber (Walker et al. 1993) at 27, 55%
RH and 16:8 hr L:D, produced adults the follow-
ing Apr and May (Portman, unpublished data).
The prolonged emergence period further contrib-
utes to the overlapping generations and lack of
distinct cohorts. Adults have been observed as
early as late Apr and as late (in the mild winters
of 2006-2007 and 2007-2008) as mid-Jan (Frank,
unpublished data). If 4 months of the year (typi-
cally mid-Dec to mid-Apr) are the period during
which L. bicolor adults are inactive, then the
number of potential generations must be reduced
from =4.5 (as they might be in the tropics) by a
third, to perhaps 3 (or even 3.5 if the first hard
frost does not arrive until mid-Jan).
The life cycle of Scapteriscus mole crickets, too,
is influenced by climate. The 2 species in northern
Florida have only 1 generation each year. They
oviposit in spring, after which overwintered
adults die. Young nymphs are not suitable hosts
for L. bicolor. These dynamics affect host avail-
ability for L. bicolor.
If the lifetime egg output of each L. bicolor fe-
male averages 56, and if there were 3 parasitoid
generations during each annual generation of the
host, and if the host's lifetime egg output averages
90 eggs (an approximation for 3 clutches spaced 3
weeks apart, each of 30 eggs), the calculation of
reproductive potential for parasitoid and host
would be simple. The parasitoid would be able to
out-reproduce the host by far.
At least by Aug there is no evidence of discrete
generations among adult wasps in the field. Stan-
dardized semi-weekly counts of adult L. bicolor
feeding in Aug-Nov 2006 on nectar of Spermacoce
verticillata in 3 plots at each of 2 sites near
Gainesville, Florida revealed average monthly
counts from Aug to Nov ranging from 25.7 to 40.7,
but only 17.2 in Jul (Portman 2007). Wasp activity
was not monitored after Nov, although it probably
continued until the first hard frost in mid-Jan
2007. The plants used were transplanted from a
greenhouse into the field in Mar 2006. Routine
monitoring of the plants for wasps began in May,
but wasps were not observed until Jul. The aver-
age monthly count of only 17.2 wasps in Jul could
have resulted from the small size of the plants at
that time (so they were less attractive than later)
or from relatively few wasps present during that
month. Host availability is very low in Jul due to


its life cycle; few overwintered adults remain
alive and nymphs are small (Walker 1985). The
overlapping of generations in L. bicolor is pro-
moted by (1) the spread in time of emergence of
adult wasps from pupae, and (2) the spread in
time due to the long ovipositional period (> 3
weeks) of each female wasp. As a result, mole
crickets are vulnerable to daily attack by the
wasps at least throughout the autumn until the
first hard frost.
Calculation of mortality caused by the wasp
during the warmer months more closely resem-
bles a study in epidemiology than it resembles a
textbook calculation of parasitoid: host relation-
ships. Special considerations for this situation are
that the level of daily attack apparently depends
upon (1) the number of eggs that each L. bicolor
female can lay per day (mean = 2.44), and (2) the
ratio of female L. bicolor to susceptible mole crick-
ets in an area at a given time. Any host found par-
asitized by an L. bicolor egg on d x would have
died and thus been removed from the population
not later than d x + 18 (maximum time for egg and
larval development). Any host found parasitized
by an L. bicolor larva on d x would have died and
thus been removed from the population not later
than d x + 11 (maximum time for all instars). The
percentage parasitism of the host by wasp eggs or
larvae is the measurable quantity in the field that
can be used to calculate generational mortality of
the host. Further research is necessary to deal
with such complex models.

ACKNOWLEDGMENTS

This work was supported by a USDA-TSTAR grant
to N. C. Leppla and J. H. Frank. A culture of Scap-
teriscus abbreviatus has been maintained for >20 yr in
Frank's mole cricket laboratory; cultures of S. vicinus
are maintained as needed; L. H. Skelley was the biolog-
ical scientist in charge at the time of need for mole crick-
ets in autumn 2006, and her work is gratefully
acknowledged. Thanks to L. J. Buss for Fig. 2, an image
of a mole cricket bearing 3 wasp eggs. We thank J. L.
Capinera and J. P. Cuda for critical reviews of an earlier
version of this manuscript, 2 unidentified helpful re-
viewers on behalf of Florida Entomologist, and J. Bram-
bila for corrections to a draft Spanish abstract.

REFERENCES CITED

CABRERA-MIRELES, H. 2002. Relationship between
Temperature and Development of the Ectoparasi-
toid Larra bicolor (Hymenoptera: Sphecidae) and
the Endoparasitoid Ormia depleta (Diptera: Ta-
chinidae). PhD. Dissertation, Univ. Florida,
Gainesville, FL.
CASTNER J. L. 1984. Suitability of Scapteriscus spp.
mole crickets (Orthoptera: Gryllotalpidae) as hosts
of Larra bicolor (Hymenoptera: Sphecidae). Ento-
mophaga 29: 323-329.
CASTNER, J. L. 1986. Response of Larra bicolor (Hy-
menoptera: Sphecidae) to parasitized and unparasit-


March 2009







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ized mole cricket hosts (Orthoptera: Gryllotalpidae:
Scapteriscus). Florida Entomol. 69: 252-255.
CASTNER, J. L. 1988. Biology of the mole cricket parasi-
toid Larra bicolor (Hymenoptera: Sphecidae), pp.
423-432 In V. K. Gupta [ed.], Advances in Parasitic
Hymenoptera Research. Brill, Leiden.
FRANK, J. H., AND WALKER, T. J. 2006. Permanent con-
trol of pest mole crickets (Orthoptera: Gryllotalpi-
dae: Scapteriscus) in Florida. American Entomol. 52:
138-144.
FRANK, J. H., PARKMAN, J. P., AND BENNETT, F. D. 1995.
Larra bicolor (Hymenoptera: Sphecidae), a biologi-
cal control agent of Scapteriscus mole crickets (Or-
thoptera: Gryllotalpidae), established in northern
Florida. Florida Entomol. 78: 619-623.
MENKE, A. S. 1992. Mole cricket hunters of the genus
Larra in the New World (Hymenoptera: Sphecidae,
Larrinae). J. Hymen. Res. 1: 175-234.
OHL, M., AND LINDE, D. 2003. Ovaries, ovarioles, and oo-
cytes in apoid wasps, with special reference to clep-
toparasitic species (Hymenoptera: Apoidea, "Sphe-
cidae"). J. Kansas Entomol. Soc. 76: 147-159.


O'NEILL, K. M. 2008. Apoid wasps (Hymenoptera:
Apoidea: Spheciformes), pp. 230-239 In J. L. Capin-
era [ed.], Encyclopedia of Entomology. Springer, Dor-
drecht.
PORTMAN, S. L. 2007. Foraging and Fecundity of Larra
bicolor (Hymenoptera: Sphecidae) a Parasitoid of
Scapteriscus Mole Crickets. MS thesis, Univ. Flori-
da, Gainesville, FL.
STEINER, A. L. 1984. Why can mole crickets stung by
Larra wasps (Hymenoptera: Sphecidae; Larrinae)
resume normal activities? The evolution of tempo-
rary paralysis and permanent deactivation of the
prey. J. Kansas Entomol. Soc. 57: 152-154.
WALKER, T. J. 1985. Systematics and life cycles, pp. 3-10
In T. J. Walker [ed.], Mole Crickets in Florida. Flori-
da Agric. Exp. Stn. Bull. 846 (1984): i-iv, 1-54. Now
online, relevant Fig. at http://buzz.ifas.ufl.edu/
g341dl.htm.
WALKER, T. J., GAFFNEY, J. J., KIDDER, A. W., AND
ZIFFER, A. B. 1993. Florida Reach-Ins: Environmen-
tal chambers for entomological research. American
Entomol. 39: 177-182.







Florida Entomologist 92(1)


TWO NEW SPECIES OF AULACORTHUM
(HEMIPTERA: APHIDIDAE) FROM KOREA

WONHOON LEE, HYOJOONG KIM AND SEUNGHWAN LEE*
Insect Biosystematics Laboratory, Research Institute for Agricultural and Life Sciences, Department of
Agricultural Bio-Technology, Seoul National University, Seoul 151-921, Korea
*Corresponding author; e-mail seung@snu.ac.kr

ABSTRACT
Two new species of the genus Aulacorthum,Aulacorthum asteriphagum sp. nov. andAula-
corthum corydalicola sp. nov., are recognized from Korea on Aster scaber Thunb. and Cory-
dalis spp. (C. pallida Pers. and C. speciosa Maxim.), respectively. They are described and
illustrated in comparison with the closely related species Aulacorthum solani Kaltenbach
1843. Aulacorthum asteriphagum is mainly characterized by many secondary rhinaria (4-
12) on Antenna III, and A. corydalicola is distinguished by short antennae (2.30-2.75 mm)
including dark Antenna III. A revised key to the identification of the Korean species ofAul-
acorthum is presented.
Key Words: Macrosiphini,Aulacorthum, Corydalis, Aster, new species, Korea

RESUME

Dos nuevas species de afidos (pulgones) del genero Aulacorthum, Aulacorthum asteripha-
gum sp. nov. yAulacorthum corydalicola sp. nov., son reconocidos de Corea, sobreAster sca-
ber Thunb. y Corydalis spp. (C. pallida Pers. y C. speciosa Maxim.), respectivamente. Estos
son descritos e ilustrados en comparaci6n con la especie cercanamente relacionada, Aulacor-
thum solani Kaltenbach 1843. Entre las species aliadas, se caracteriza Aulacorthum aste-
riphagum sp. nov. principalmente por tener muchas rinarias (sensorias) secundarias (4-12)
sobre Ant.III (tercer segment del antena); se distingue Aulacorthum corydalicola sp. nov.
por la corta longitud de su antena (2.30-2.75 mm), incluyendo el segment Ant. III oscuro.
Una clave para la identificaci6n de las species deAulacorthum de Corea es incluida.


The genus Aulacorthum Mordvilko 1914 is a
Palaearctic and Oriental genus with 40 species
known in the world (Remaudiere & Remaudiere
1997; Lee 2002; Eastop & Blackman 2005; Lee &
Kwon 2006). This genus consists of 2 subgenera:
the nominotypical Aulacorthum (38 species) and
Perillaphis Takahashi 1965 (2 species). Morpho-
logically, the genusAulacorthum is well character-
ized by "head with well developed antennal tuber-
cles, inner sides of tubercles nearly parallel; me-
dian tubercle on frons hardly developed; head usu-
ally granulate in apterous; first tarsal chaetotaxy
3:3:3; siphunculi cylindrical, or slightly swollen,
normally broad at base, rather long with usually a
few row of flat hexagonal cells at apex under broad
distal flange; cauda tongue-shaped with 4-8 setae,
mostly 7 setae." (Heie 1994). They are not host-al-
ternating, and are mostly monoecious holocyclic.
Previously, 12 species of the genus Aula-
corthum have been reported from Korea. Since
Shinji (1941) recorded A. nipponicum (Essig &
Kuwana 1918). Paik (1965, 1972) reported 7 spe-
cies, as follows: A. asteris Takahashi 1965, A. cir-
sicola (Takahashi 1923), A. ibotum (Essig & Ku-
wana 1918), A. magnoliae (Essig & Kuwana
1918), A. nepetifolii Miyazaki 1968, A. perillae
(Shinji 1965) andA.solani (Kaltenbach 1843). Lee
& Seo (1990) addedA. glechomae Takahashi 1965.


Recently Lee (Lee 2002; Lee & Kwon 2006) de-
scribed 2 new species, A. ligularicola Lee 2002
and A. albimagnoliae Lee and Kwon 2006, and
Lee et al. (2008) recorded A. muradachi (Shinji
1928).
In this present paper, 2 new species are de-
scribed and compared with the most closely re-
lated species, and a revised key to species ofAul-
acorthum of the Korean Peninsula is provided.

MATERIALS AND METHODS

Aphid samples for this study were collected in
1970-1971, 1999-2000, and 2006 on Aster scaber
and Corydalis spp. (C. pallida and C. speciosa) in
South Korea. Each sample of aphid colonies was
preserved in 80% alcohol, and mounted speci-
mens were prepared in Canada balsam, following
methods by Blackman & Eastop (2000) and Mar-
tin (1983). Illustrations for each species were
taken by digital camera, Diagnostic Instruments,
Inc. 14.2 Color Mosaic attached on the micro-
scope, Leica DM 400B at a resolution of 600 dpi.
Measurements for each specimen are taken from
the digital images by the software, Image Lab ver-
sion 2.2.4.0 by MCM Design (Ltd.).
The type specimens, including holotype, are
deposited in the College of Agriculture and Life


March 2009







Lee et al.: New Species of Aphid


Sciences, Seoul National University (CALS
SNU), Seoul, Korea and some paratypes in the
National Institute of Agricultural Sciences and
Technology (NIAST), Suwon, Korea.
Abbreviations used for descriptions and table
are as follows: al. alate viviparous female, alata;
apt. apterous viviparous female, aptera; Ant. -
antennae; Ant.I, Ant.II, Ant.III, Ant.IV, Ant.V,
Ant.VI, and Ant.VIb antennal segments I, III,
IV, V, VI, and base of VI, respectively; BDAnt.III -
basal diameter of antennal segment III; BL -
length of body; GP genital plate; 2HT second
segment of hind tarsus; PT processus terminalis;
SIPH siphunculi; URS ultimate rostral seg-
ment (segment IV + V).

SYSTEMATIC ACCOUNTS

Genus Aulacorthum Mordvilko 1914

Subgenus Aulacorthum sensu strict

Aulacorthum Mordvilko 1914, Faude de la Russie Ins.
Hemipt., 1(1): 68.

Dysaulacorthum Bdrner 1939.

Melanosiphon Bdrner 1944.

Neomacrosiphum van der Goot 1915.

Type species:Aphis solani Katenbach 1843.

Aulacorthum corydalicola Lee, Kim & Lee sp. nov.
(Figs. 1-3, Table 1)

Description: Apterous Viviparous Female.
Color (alive): Body including head, thorax, and
abdomen pale green. Antenna fuscous. Leg pale
except distal 1/5 of femora, distal 1/5 of tibiae in-
cluding tarsi black. SIPH and cauda pale. Color
(macerated specimens): Head pale. Ant.I-II en-
tirely pale but Ant.III-VI dusky excluding Ant.III
pale at base. Rostrum a little dusky except very
end of URS dark brown. Thorax and abdomen
pale. Cauda and SIPH pale except extreme end of
SIPH dusky. Legs pale except distal 1/5 of femora,
distal 1/9 of tibiae, and tarsi dark brown.
Morphology: Body spindle shaped. Head:
spinulose on whole surface of dorsum and ven-
trum, 3 pairs of acuminate setae on dorsum. An-
tennal tubercle well developed with 2-3 setae on
both side, frons U-shaped with 4 setae on vertex.
Ant.I spinulose ventrally; Ant.II spinulose;
Ant.III weakly imbricate with short setae, bear-
ing 1-2 secondary rhinaria at base; Ant.IV imbri-
cate with 8-17 setae; Ant.V imbricate with 5-10
setae, primary rhinarium ciliate, longest diame-
ter shorter (0.75-0.87 times) than middle width of
Ant.V; Ant.VI imbricate with 3-5 short setae on
Ant.VIb. Rostrum attaining posterior margin of
mesocoxa; clypeus with 4 setae; URS longest seta


0.58-0.63 times as long as apical primary ones.
Thorax: pronotum smooth with 2 spinal setae and
1 marginal seta on anterior margin. Hind coxa
weakly spinulose with 10-13 acuminate setae;
hind trochanter wide at base, 1.42-1.58 times as
long as apical width, bearing 3 setae; hind femur
smooth on basal 2/3, spinulose on apical 1/3 ven-
trally, bearing short setae, longest seta 0.26-0.30
times as long as basal width of segment; hind
tibia smooth with short setae, longest seta as long
as middle width of segment; first segment of each
tarsus smooth with three setae at apex; 2HT im-
bricate with 9-12 setae. Abdomen: dorsum
smooth, membranous with 8 setae on tergite III,
spinal 4 setae minute (less than ca. 0.15 times
basal width of hind femur), marginal setae 0.22-
0.27 times basal width of hind femur. SIPH cylin-
drical, basal 1/2 weakly spinulose except smooth
base, distal 1/2 imbricate, irregularly reticulated
on distal end, apex well flanged. Cauda elongate,
triangular, ventral spinules strong, dense, in
groups of 1 or 2; dorsal ornamentation composed
of ribbed imbrication.

Alate Viviparous Female

Color (alive): Pale green with antennae black.
Head and thorax black. Abdomen with black
patches on tergite III-VI. Color (macerated speci-
mens): Antenna entirely dark except basal
Ant.III pale. Thorax dark brown. Abdomen with
irregular transverse dark band on each segment.
Wings pale with veins bordered by narrow dark
pigmentation.
Morphology: Antennae with 1-7 secondary rhi-
naria in a line on whole Ant.III. Cauda triangu-
lar, pointed at apex. SIPH strongly imbricated
and weakly reticulated at apex. Otherwise like
apterous viviparous female.
Host and Distribution: So far collected and ob-
served on Corydalis pallida and Corydalis spe-
ciosa in Namhae-gun, Gyeongsangnam-do and
Gwanak-arboretum, Gyeonggi-do, Korea.
ErL, ..... .,.,: The species name is derived from
the genus name of host plants (Corydalis spp.)
and the Latin suffix, -cola (dweller, inhabitant).
Specimens Examined: Holotype: apterous vi-
viparous female, Coll#.990331-SH-3/ap.16,
Idong-myeon, Namhae-gun, Gyeongsangnam-
do, Korea, 31-III-1999, on Corydalis pallida
Pers., leg. Seunghwan Lee. Paratypes: 44 apter-
ous viviparous females, 2 alates viviparous fe-
males, same date as holotype; 10 apterous vivip-
arous females, Coll#.060408-SH-9, Jingyo-my-
con, Hadong-gun, Gyeongsangnam-do, Korea, 8-
IV-2006, on C. pallida, leg. Seunghwan Lee; 19
apterous viviparous females, 2 alate viviparous
females, Coll#.060509-WH-1, Gwanak arbore-
tum, Manan-gu, Anyang-si, Gyeonggi-do, Korea,
9-V-2006, on Corydalis speciosa Maxim., leg.
Wonhoon Lee.







Florida Entomologist 92(1)


March 2009


Fig. 1. Alate viviparous female (A-H) and apterous viviparous female (I-P) ofAulacorthum corydalicola sp. nov.
A, whole body of alate vivipara. B, siphunculus. C, hind tibia and tarsus. D, antennal segments III-IV. E, antennal
segments V-VI. F, head focused on dorsum. G, ultimate rostral segment. H, cauda. I, whole body of apterous vivi-
para. J, SIPH. K, hind tibia and tarsus. L, antennal segments III-IV. M, antennal segments V-VI. N, head focused
on dorsum. 0, ultimate rostral segment. P, cauda.

Biology: Colonies of individual aphid were ob- from underside of leaves. Considering the early
served on the young leaves, flowers, or seed pad of establishment of colonies on Corydalis spp. from
the host plants. Many samples were collected the end of Mar, this new species seems to be mo-







Lee et al.: New Species of Aphid


Fig. 2. Photograph ofAulacorthum corydalicola sp. nov. apterous viviparous female.


noecious holocyclic on Corydalis spp. However, it
has not been determined where the summer gen-
eration survives, when the host plant loses
leaves, and how the aphids overwinter on the host
plant.
Remarks: In the general body shape and the
coloration of live apterous females, this species is
similar to Aulacorthum solani from which it dif-
fers by short antenna 2.30-2.75 mm (vs long an-
tenna 2.92-3.56 mm for solani), 0.96-1.19 times as
long as BL (vs 1.16-1.33 times for solani); Ant.I
strongly spinulose (vs Ant.I smooth or weakly
spinulose for solani); Ant.III-VI dark (vs Ant.III-
VI pale excluding each dark junction of Ant.III-VI
for solani), URS 0.93-1.07 times as long as
Ant.VIb (vs URS 1.06-1.27 times for solani), and
short hind tibia 1.28-1.71 mm (vs long hind tibia
1.64-2.05 mm for solani), and living only on Cory-
dalis spp.


Aulacorthum asteriphagum Lee, Kim & Lee sp. nov.
(Fig. 4, Table 1)
Description: Apterous Viviparous Female.
Color (macerated specimens): Head pale ex-
cept dusky outside of antenna tubercle. Ant.I-III
fuscous, Ant.IV-VI pale excluding each dark junc-
tion of Ant.IV-VI. Rostrum pale except very end of
URS dark brown. Thorax and abdomen pale.
Cauda and SIPH pale except extreme end of SIPH
dusky. Legs pale except distal 1/3-1/5 of femora,
distal 1/10 of tibiae, and tarsi dark brown.
Morphology: Body spindle shaped. Head:
spinulose on whole surface of dorsum and ven-
trum, 3 pairs of acuminate setae on dorsum. An-
tennal tubercle well developed with 2 setae, frons
U-shaped with 2 pairs of setae on vertex. Ant.I
spinulose dorsally and ventrally; Ant.II granu-
late; Ant.III imbricate with minute setae, bearing
4-12 secondary rhinaria in a line at regular dis-







Florida Entomologist 92(1)


fl^^DI -Ir
IAr'. r;


Fig. 3. Photograph ofAulacorthum corydalicola sp. nov. alate viviparous female.


tances; Ant.IV imbricate with 8-13 setae; Ant.V
imbricate with 4-8 setae, primary rhinarium cili-
ate, longest diameter shorter (0.78-0.86 times)
than middle width; Ant.VI imbricate with 3-5
short setae on Ant.VIb. Rostrum attaining poste-
rior margin of hindcoxa; clypeus with 4 setae;
URS longest seta 0.58-0.76 times as long as apical
primary ones. Thorax: pronotum smooth with 2
short blunt spinal setae and 1 anterior marginal
setae. Hind coxa weakly spinulose with 8-9
acuminate setae; hind trochanter wide at base,
1.43-1.67 times as long as apical width, bearing 3
setae; hind femur smooth on basal 1/2, spinulose
on apical 1/2 ventrally, bearing short setae, long-
est seta 0.18-0.31 times as long as basal width of
segment; hind tibia smooth with short setae, long-
est seta as long as middle width of segment; first
segment of each tarsus smooth with 3 setae at
apex; 2HT imbricate with 8-10 setae. Abdomen:
dorsum smooth, membranous with 8 setae on
tergite III, spinal 4 setae minute (less than ca.
0.01 times basal width of hind femur), marginal
setae 0.01 times basal width of hind femur. SIPH
cylindrical, imbricate except weakly spinulose at
base, irregularly reticulated on distal end, apex
well flanged. Cauda elongate, triangular, ventral


spinules strong, dense, in groups of 1 or 2; dorsal
ornamentation composed of ribbed imbrications.
Host and Distribution: So far collected only on
Aster scaber in Bongpyeong-myeon, Pyeo-
ngchang-gun, Gangwon-do, Korea.
ErL, ...... ..,: The species name is derived from
the genus name of host plants (Aster scaber).
Specimens Examined: Holotype: apterous vi-
viparous female, Coll#.000607-SH-9/ap.5, He-
ungjeong-ri, Bongpyeong-myeon, Pyeongchang-
gun, Gangwon-do, Korea, 7-VI-2000, on Aster
scaber Thunb., leg. N. S. Bong. Paratypes: 1
apterous viviparous females Coll#.5876, Seoul,
Korea, 6-V-1970 onA. scaber, leg. Woonhah Paik;
4 apterous viviparous females Coll#.6891, Seoul,
Korea, 3.xi.1971 onA. scaber, leg. Woonhah Paik;
1 apterous viviparous female, 2 nymphs, same
date as holotype; 4 apterous viviparous females,
Coll#.000727-SH-1, Bongpyeong-myeon, Pyeo-
ngchang-gun, Gangwon-do, Korea, 27-VII-2000
on A. scaber, leg. N. S. Bong; 1 nymph,
Coll#.000927-SH-9, Bongpyeong-myeon, Pyeo-
ngchang-gun, Gangwon-do, Korea, 27-IX-2000,
on A. scaber, leg. N. S. Bong.
Biology: Colonies were observed on undersides
of leaves of host plants. Colonies of this species


March 2009








Lee et al.: New Species of Aphid


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Lee et al.: New Species of Aphid


izi, Z!1 :


Fig. 4. Apterous viviparous female (A-I) of Aulacorthum asteriphagum sp. nov. A, whole body. B, siphunculus.
C, hind tibia and tarsus. D, antennal segments III-IV. E, antennal segments V-VI. F, head focused on dorsum. G, tar-
sus. H, ultimate rostral segment. I, cauda.


seem to be very rare. After collecting the type, au- corthum corydalicola sp. nov. from which it dif-
thors failed to collect any additional samples. fers by head pale excluding outside of antenna
Remarks: In the general body shape, this spe- tubercles dusky, Ant.I-II fuscous (vs head and
cies is similar to Aulacorthum solani and Aula- Ant.I-II pale for combined values of corydalicola


'
- 1
~







Florida Entomologist 92(1)


sp. nov. and solani), 4-12 secondary rhinaria in a cola sp. nov. and solani), rostrum attaining poste-
line at regular distances on whole Ant.III (vs 0-3 rior margin of hindcoxa (vs rostrum attaining
secondary rhinaria confined to basal half on posterior margin of mesocoxa for combined values
Ant.III for combined values of corydalicola sp. of corydalicola sp. nov. and solani), and URS 1.29-
nov. and solani); PT 1.06-1.31 mm, 5.37-6.61 1.67 times as long as 2HT (vs URS 0.93-1.29
times as long as Ant.VIb(vs PT 0.55-1.02 mm, times for combined values of corydalicola sp. nov.
3.06-5.84 times for combined values of corydali- and solani), living on Aster scaber (Asteraceae).

KEY TO SPECIES OF AULACORTHUM IN KOREA, INCLUDING SOME POLYPHAGOUS
SPECIES (BASED ON APTEROUS VIVIPAROUS FEMALE)

1. SIPH pale, concolorous with abdominal tergite, at most dusky at apex ............................... 2

-SIPH black, at least dusky wholly, not concolourous with abdominal tergite ............................. 7

2. Antennal tubercles gibbous, convergent. Leg pale. Body including appendages pale yellow in life except nar-
row dark band of joints between antennal segments. On the genus Glechoma (Labiatae). In Korea and
Japan ........................................................ Aulacorthum glechom ae

-Antennal tubercles divergent. Leg pale but dark at apex of femora or tibiae. Body pale green in life ......... 3

3. Head spinulose dorsally. Dorsal surface of antennal tubercle entirely spinulose ..........................

-Head smooth dorsally. Dorsal surface of antennal tubercle smooth, partly spinulose at most ............... 5

4. Head partly spinulose on ventrum. Antenna pale; Ant.I-II smooth; PT short (3.78-5.54 times as long as Ant.VIb).
Femora entirely pale. Apical reticulation of SIPH developed (more than 3 rows of cells). On the genus Mag-
nolia (Magnoliaceae). In Korea. ...................................... Aulacorthum albimagnolia

-Head entirely spinulose on ventrum. Antenna pale excluding dark apices? of Ant.III-VIb; Ant.I-II spinulose or
granulate; PT long (5.25-7.35 times as long as Ant.VIb). Femora pale except distal third dark brown. Apical
reticulation of SIPH weakly developed (1-2 rows of cells). On the genus Cirsium (Asteraceae). In Korea and
Japan ................................................................ Aulacorthum cirsicola

5. 4-12 secondary rhinaria on whole Ant.III; PT 5.37-7.24 times as long as Ant.VIb. URS 1.29-1.67 times as long as 2HT;
Rostrum attaining posterior margin of hindcoxa. On Aster scaber Thunb. (Asteraceae)
................ ............................................. Aulacorthum asteriphagum sp. nov.

-0-3 secondary rhinaria confined to basal half on Ant.III; PT 3.06-5.85 times as long as Ant.VIb. URS 0.93-1.27
times as long as 2HT; Rostrum attaining posterior margin of mesocoxa .......................... 6

6. Antenna 0.96-1.19 times as long as BL; Ant.III-VI dark; PT 0.55-0.67 mm, 3.06-4.07 times as long as Ant.VIb.
On Corydalis pallida Pers. and Corydalis speciosa Maxim. (Papaveraceae)
........................................................ Aulacorthum corydalicola sp. nov.

-Antenna 1.16-1.33 times as long as BL; Ant.III-VI pale excluding dark junction of Ant.III-VI.b; PT 0.85-1.02 mm,
3.57-5.85 times as long as Ant.VIb. On various plants. In almost world-wide countries
.............................................. .. ................... A ulacorthum solani

7. Abdominal tergum dark, pigmented entirely or marginally in apterae. On the genus Nepeta (Labiatae). In Korea
and Japan. ......................................................... Aulacorthum nepetifolii

-Abdominal tergum pale, not pigmented in apterae.................................................. 8

8. SIPH slightly swollen........................................................................ 9

- SIPH cylindrical, not swollen .................................................................. 10

9. Abdomen with small distinct antesiphuncular sclerites. SIPH black, widest at base. Body usually small, less
than 3.0 mm in length. On the genus Paederia (Rubiaceae). In Korea, Japan, China, Taiwan, Thailand,
India ........................................................ Aulacorthum nipponicum

-Abdomen without antesiphuncular sclerite. SIPH pale, at most dusky, widest in middle. Body usually large, more
than 3.5 mm in length. On the genus Sambucus and other plants. In Far East Asia (Korea, Japan, China),
India, Siberia ....................................................... .Aulacorthum magnolia

10. Antennae with more than 17-29 secondary rhinaria on Ant.III. Body wholly pale yellow in life, except si-
phuculi, apex of femora and tibiae and antennae black partly. On the genus Aster (Asteraceae). In Ko-
rea and Japan .................................................... Aulacorthum asterisk


March 2009







Lee et al.: New Species of Aphid


-Antennae with less than 17 secondary rhinaria on Ant.III. Body mottled with black or reddish brown on abdomen
in life . . . . . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ... 1 1

11. SIPH less than 2 times as long as cauda. Body pale yellow, mottled with dark green and black on abdomen
laterally and around SIPH in life. On the genus Ligustrum (Oleaceae). In Korea and Japan
................................................................ A ulacorthum ibotum

-SIPH long, 3 times as long as cauda. Body pale, mottled with reddish brown on abdomen laterally and around
SIPH in life .................. ....................................................... 12

12. Head spinulose dorsally and ventrally. Ant.III pale, smooth with 5-17 secondary rhinaria. Hind tibiae pale ex-
cept dark distal end. SIPH dusky. Abdominal tergite VIII with 6-8 setae. On the genus Ligularia (Aster-
aceae). In Korea. .................................................... Aulacorthum ligularicola

-Head smooth, at least on dorsum. Ant.III dark brown at basal half with 1-3 secondary rhinaria. Hind tibiae dark
brown or black on basal half. SIPH black. Abdominal tergite VIII with 4 setae. On the genus Parabenzoin
and Lindera (Lauraceae). In Korea and Japan ............................ Aulacorthum muradachi


ACKNOWLEDGMENT

The authors thank Dr. R. L. Blackman, the Natural
History Museum, London, UK, for advice and reading of
the manuscript. This research was supported by Korea
Ministry of Environment as "The Eco-technopia 21
project."


REFERENCES CITED

BLACKMAN, R. L., AND EASTOP, V. F. 2000. Aphids on
the World's Crops. An Identification and Information
Guide (Second Edition), J. Wiley & Sons, Chichester.
BORNER, C. 1939. Neue Gattungen und Arten der mit-
teleuropaischen Aphidenfauna. Arb. Phys. Angew.
Ent. 6(1): 75-83.
EASTOP, V. F., AND BLACKMAN, R. L. 2005. Some new
synonyms in Aphididae (Hemiptera: Sternorrhyn-
cha). Zootaxa (1089): 1-36.
GOOT, P. VAN DER 1915. Beitrage zur Kenntnis der
hollandischen Blattlause. viii+600 pp.
HEIE, O. E. 1994. The Aphidoidea (Hemiptera) of Fen-
noscandia and Denmark. V Family Aphididae: Part
2 of tribe Macrosiphini of subfamily Aphididae. Fau-
na Entomologica Scandinavica.
KALTENBACH, J. H. 1843. Monographie der Familien der
Pflanzenlause (Phytophthieres). XLIII. 233 pp.
LEE, S. H. 2002. A new genus, Codonopsimyzus, and
two species of macrosiphine aphids (Hemiptera:


Aphididae) from Korea. Canadian Entomol. 134:
633-646.
LEE, S. H., AND KWON, M. 2006. A new aphid of the ge-
nus Aulacorthum (Hemiptera: Aphididae) on Mag-
nolia sieboldii K. Koch (Magnoliaeceae) from Korea.
Pan-Pacific Entomol. 82: 332-340.
LEE, W. K., AND SEO, H. Y. 1990. Systematic studies on
aphids of Korea. 1. Tribe Marcosiphini. Korean J.
Entomol. 20: 197-212.
LEE, W., KIM, H., AND LEE, S. 2008. One New Record of
the Genus Aulacorthum Mordvilko (Hemiptera: Ah-
phididae) from Korea. J. Asia-Pacific Entomol. (in
press).
MARTIN, J. 1983. The identification of common aphid
pests of tropical agriculture. Tropical Pest Manage-
ment 29: 395-411.
MORDVILKO, A. K. 1914. Aphidodea I. Faune de la Russie
(Insecta: Hemiptera). Insectes. H6mipteres 1: 236 pp.
PAIK, W. H. 1965. Aphids of Korea. Publishing Center of
Seoul National University, Seoul, Korea.
PAIK, W. H. 1972. Illustrated Encyclopedia of Fauna &
Flora of Korea. Insecta (V).
REMAUDIERE, G., AND REMAUDIERE, M. 1997. Catalogue
of the world's Aphididae. Homoptera Aphidoidea. In-
stitut National de la Recherche Agronomique.
SHINJI, O. 1922. New genera and species of Aphididae of
Japan. Dobutsugaku Zasshi (Zool. Mag.), 34(407):
708-800.
SHINJI, O. 1941. Monograph of Japanese Aphididae. To-
kyo.







Florida Entomologist 92(1)


March 2009


USE OF LANDSCAPE FABRIC TO MANAGE
DIAPREPES ROOT WEEVIL IN CITRUS GROVES

L. W. DUNCAN,' R. J. STUART', F. G. GMITTER2 AND S. L. LAPOINTE3
'Department of Entomology and Nematology and 2Department of Horticultural Sciences, University of Florida,
IFAS, Citrus Research and Education Center, 700 Experiment Station Road, Lake Alfred, FL 33850

3U. S. Horticultural Research Lab, U. S. Department of Agriculture-ARS, 2001 S. Rock Road, Ft. Pierce, FL 34945

ABSTRACT

Experiments were conducted at 3 sites in Florida to determine whether landscape fabric,
used as soil mulch, can reduce damage to citrus trees by Diaprepes abbreviatus. The mulches
were intended to prevent newly hatched weevil larvae from entering the soil to feed on roots
and to prevent general adult weevils from exiting the soil to initiate egg-laying. The weight
of aboveground parts of trees at a site heavily infested by D. abbreviatus on the east coast
was 70% larger (P < 0.05) for trees grown for 3 years on mulched compared to unmulched
soil. Mulching did not affect the amount of feeding damage to roots at the east coast site, sug-
gesting that mulched trees tolerated the damage better than trees in bare soil. Small plot
size and relatively narrow fabric dimensions at the east coast site may have facilitated the
entry of neonate larvae into soil. At a site on the Central Ridge with low weevil population
density, average trunk cross-sectional area of 5-year-old mulched trees was 31% greater (P
< 0.02) than trees in bare soil. At both this site and a central flatwoods site, the number of
adult weevils captured in ground traps that catch weevils emerging from soil was reduced
by up to 99% when traps were installed next to trees on mulch compared to bare soil. Adult
weevils did not appear to migrate beneath fabric to emerge at the edges because mean num-
bers of weevils trapped at the edges of the fabric (2.75 1.01) did not differ (P > 0.05) from
those trapped at the same position on unmulched trees (4.38 1.95). Additional work is
needed to demonstrate the effect of fabric mulches on weevil population density. Neverthe-
less, fabric mulches were shown to consistently increase tree growth in weevil-infested or-
chards. Fabric mulches also eliminate the need for herbicides and potentially insecticides or
other IPM tactics to manage root weevil pests.

Key Words: Diaprepes abbreviatus, Artipus floridanus, mulch, cultural control, physical bar-
rier, landscape fabric

RESUME

Se realizaron experiments en 3 sitios de la Florida para determinar si la tela sint6tica para el
jardin, usada como un mantillo del suelo, puede reducir el dano a los arboles de citricos por Dia-
prepes abbreviatus. La intenci6n de poner el mantillo fue para prevenir que las larvas reci6n na-
cidas del picudo entraran el suelo para alimentarse sobre las races y para prevenir que los
picudos adults tenerales salgan del suelo para iniciar la ovisposici6n. El peso de las parties de
los arboles que estan arriba de la tierra en sitios muy infestados por D. abbreviatus en la costa
este fue 70% mas alto (P < 0.05) para los arboles sembrados en mantillo por 3 afios en compara-
ci6n con los sembrados en suelo sin mantillo. El puesto del mantillo no afecto la cantidad del
dano causado por la alimentaci6n de las races en el sitio el la costa este, sugiriendo que los ar-
boles sembrados en mantillo toleraron el daho mejor que los arboles sembrados solamente en
suelo desnudo. El tamano pequefio de las par6celas y la dimension relativamente estrecha de la
tela usada en el sitio de la costa este puede haber facilitado la entrada de las larvas reci6n naci-
das al suelo. En el sitio de la Cresta Central con una densidad de poblaci6n mas baja del picudo,
el promedio de la area cruce seccional de los arboles sembrados en mantillo por 5 aios fue 31%
mayor (P < 0.02) que la en suelo desnudo. En este sitio y en el sitio con el drenaje del suelo im-
pedido, el numero de los adults de picudos capturados emergiendo del suelo en las trampas del
suelo fue reducido hasta 99% cuando las trampas fueron instaladas a la par de los arboles sem-
brados en mantillo en comparaci6n con los arboles en suelos desnudos. Los picudos adults no
aparentan emigrar debajo de la tela para merger por los bordes porque el numero promedio de
los picudos capturados en los bordes de la tela (2.75 1.01) no fue diferente (P > 0.05) que el nu-
mero capturado en la misma posici6n en los arboles no sembrados en mantillo (4.38 1.95). Se
necesita trabajo adicional para mostrar el efecto de los mantillos hechos de tela sobre la densidad
de la poblaci6n de picudo. Sin embargo, se mostr6 que el uso de los mantillos de tela aumento
consistemente el crecimiento de arboles en huertos infestados con picudo. Los mantillos de tela
tambi6n eliminaron la necesidad para usar herbicidas e insecticides u otras tacticas de MIP para
el manejo de los picudos de las races como plaga.







Duncan et al.: Landscape Fabric to Manage Diaprepes Root Weevil


The tropical root weevil, Diaprepes abbrevia-
tus (L.), is a serious pest of citrus found through-
out the Caribbean Basin and in all citrus produc-
ing regions of Florida. There are no current esti-
mates of the economic importance of the weevil,
but a decade ago it was thought to cause losses of
$75-100 million to citrus industries in Florida and
the Caribbean (McCoy 1999). Despite being
present in the state since at least 1964, the above-
ground stages of the insect have not come under
significant natural control in citrus groves (Peia
et al. 2006). However, predation of subterranean
larval stages by endemic entomopathogenic nem-
atodes may regulate D. abbreviatus populations
on the deep sandy soils of the Central Ridge (Dun-
can et al. 2003, 2007; Futch et al. 2005).
At latitudes below 29N in Florida, D. abbre-
viatus oviposits and develops through its life cycle
during all but the coldest months (Duncan et al.
2007; Lapointe et al. 2007). Adult weevils lay eggs
on foliage and neonate larvae fall to the soil where
they develop for several months while feeding on
progressively larger roots. Root feeding can facili-
tate infection by Phytophthora nicotiana or P.
palmivora and the resulting pest-disease complex
can kill trees (Graham et al. 2003). The weevil pu-
pates in the rhizosphere and general adults
emerge from soil to initiate egg-laying during
most of the year. Management tactics currently
available to growers (insecticides applied to foli-
age and entomopathogenic nematodes applied to
soil) have short persistence and are only modestly
successful due to the continual recruitment of ne-
onate larvae into the soil and general adults into
the canopy (McCoy et al. 2004). Because registra-
tion of pesticides with long residual activity is un-
likely, improved management of D. abbreviatus
will probably require advances in host plant resis-
tance, or biological or cultural control tactics.
Physical barriers that prevent weevils from
entering and/or exiting soil would break the wee-
vil life cycle. Barriers in the form of mulches could
reduce irrigation frequency and reliance on herbi-
cides and insecticides. McKenzie et al. (2001)
tested several types of landscape fabric as barri-
ers to soil entry by neonate D. abbreviatus. The 2
most successful fabrics reduced soil entry by lar-
vae between 95% and 100% during 48 h in labora-
tory trials. In this paper we report results of field
experiments using one or both of these fabrics as
mulches beneath citrus trees at different loca-
tions in Florida.

MATERIALS AND METHODS

East Coast Flatwoods Site

Altogether, 270 budded citrus trees (Citrus sin-
ensis 'Midsweet' on C. volkameriana 'Volkamer
lemon') were planted in Feb 2001, at the Univer-
sity of Florida's Indian River Research and Edu-


cation Center at Fort Pierce, FL. Budded trees
(approximately 30 cm tall) were planted at 1.5 m
intervals within single-bed rows, approximately
triple the recommended density for commercial
groves. The grove was located on a poorly drained
hydric (Winder) soil, subject to seasonal flooding
for short periods of time. All trees were fertilized
monthly with 113 g/tree during 2001 and 150 g/
tree during 2002 of 10-10-10 with minor nutri-
ents. During 2003, trees received 680 g/tree of 6-
6-6 NPK. Trees were watered by microjet irriga-
tion as needed. A randomized block design with 3
replicates of 3 treatments was used. Replicates
consisted of 30 trees in single rows. Treatments
included a no-mulch control, and 2 mulch treat-
ments consisting of Dalen Weed-X commercial
landscaping fabric (spun polyester/polyolefin bi-
layer, Dalen Products Inc., Knoxville, TN), and
Lumite 994GC, a woven polyester landscaping
fabric (Synthetic Industries, Gainesville, GA). For
each of the 2 landscaping fabric treatments, 2
sheets of fabric (0.91 meters wide) were laid, one
on each side of a row to be planted with trees and
overlapped by 0.3 meters thereby covering a
width of 1.5 m. Holes were cut in the fabrics to
plant the trees and a circular piece of the respec-
tive fabric, cut from the periphery to the center
point, was placed around the base of each tree to
provide coverage of the soil where the fabric had
been cut to plant the tree.
To determine the number of root weevil larvae
(D. abbreviatus and P litus) infesting roots and to
assess root damage, every third tree (a total of 10
trees per replicate) was destructively sampled in
Jan, 2002, 2003, and in Dec 2003. Sampled trees
were manually uprooted with shovels. The stem
was severed to separate scion from rootstock and
the 2 portions were weighed separately. Roots and
their associated soil were separated by hand. The
roots, soil, and the soil remaining within the root
zone (defined as a cylinder of soil with diameter
equal to the diameter of the tree canopy and an
average depth of 30 cm) were examined for the
presence of root weevil larvae (D. abbreviatus and
P litus) for a minimum of 3 min by 2 field workers.
Larvae were collected in vials and returned to the
laboratory where they were weighed within 4 h of
excavation.

Central Ridge and Central Flatwoods Sites

Lumite 994GC fabric mulch treatments were
also evaluated in experiments at 2 sites in Cen-
tral Florida. The Central Ridge site is at the UF-
IFAS Citrus Research and Education Center at
Lake Alfred. Diaprepes abbreviatus was detected
at the site in 1990, but population densities have
not grown to seriously damaging levels. Artipus
floridanus, a weevil with a life history similar to
D. abbreviatus, although less damaging to citrus,
is also endemic at the site. Soil type is a deep,







Florida Entomologist 92(1)


well-drained entisol (Astatula sand) typical of
the Central Ridge. At the Central Flatwoods
site near Poinciana, the soil is a poorly drained,
loamy mollisol. The site has a long history ofD.
abbreviatus at population densities high
enough to preclude profitable citrus production
(McCoy et al. 2004).
The experimental design was a paired com-
parison of bare and mulched soil surfaces with
10 pairs of plots at the Central Ridge site and 8
pairs at the Central Flatwoods site. At the Cen-
tral Ridge site, a single row of newly planted
seedlings was used for the experiment. Each
plant was genetically distinct and from a single
family of hybrids of USDA 17-47 (Citrus gran-
dis x Poncirus trifoliata) and Kinkoji (C. obo-
voidea) planted in Aug 2002 at a spacing of 1.3
x 6.4 m. Plots consisted of 5 adjacent seedlings
and there were no border trees between plots.
The first 5 pairs of treatments were on level soil
and the remaining 5 pairs were on a fairly steep
easterly downward slope. In Sep 2002, the soil
surface of half of the plots was covered with Lu-
mite fabric. Trenches 20 cm deep were dug the
length of the plot (11.5 m) at a distance of 1.52
m from each side of the trees. One edge of a
panel of the fabric was buried in the trench. A
slit was cut in the fabric at each tree trunk to al-
low the panel to be stretched tightly across the
soil to a distance of 15 cm beyond the midline of
the plot where it was secured with metal pins.
The same operation was performed on the oppo-
site side of the plot, resulting in mulch panels
3.04 x 6.5 m with 0.3 m mulch overlap at the
midline of the plot. The plots at the Central
Flatwoods site consisted of pairs of adjacent
mature, 20-year-old Hamlin orange trees
(C. sinensis) on Swingle citrumelo roostocks
(Poncirus trifoliata x C. paradise) spaced at 4.6
x 8.2 m, with 2 rows on 18.2 m-wide beds. In Feb
2007, fabric mulch treatments were established
as at the Central Ridge site, except that all
edges were secured with metal pins. The mulch
dimensions at this site were 3.3 x 9.2 m, cen-
tered on the 2 trees.
Tree trunk diameters at 30 cm above soil
level were measured immediately after treat-
ments were established and periodically, there-
after, for 60 months at the Central Ridge site.
Conical wire mesh traps (Duncan et al. 2001)
were installed beneath each tree (200 cages) in
Apr 2006 and monitored weekly for general
adult weevils that emerged from bare soil or
mulched soil. The area at the base of traps was
0.65 m2. When treatments were initiated at the
Central Flatwoods site, 2 conical traps were es-
tablished in-row on either side of each tree in a
plot (4 traps per plot) and monitored weekly for
four months for emergent adult weevils. On 7
Jul 2008, four conical traps were installed equi-
distiant from one another along the edge of each


side of the landscape cloth (8 traps per plot)
with half of the trap base area on the fabric and
the remainder on bare soil. Traps were also in-
stalled at the same distance from the row center
in control plots. These traps were monitored for
3 months to help establish whether general
adults migrated beneath the cloth to emerge at
the edges.
Ant foraging activity on mulched and bare
plots was assessed at the Central Ridge site with
a hamburger bait assay. Raw hamburger was
placed on filter paper in open plastic dishes (4 mm
high x 48 mm dia., Millipore petrislide containers,
Millipore Corporation, Bedford, MA). The outside
and inside vertical surfaces of the dishes were
roughened with sand paper to facilitate the en-
trance and exit of the ants (Stuart et al. 2003). A
single dish was placed next to the trunk of each
tree (n = 100) between 1400 h and 1500 h on 13
May 2004. Each dish was left open for 30 min, and
was then covered with a plastic lid, which trapped
all the ants currently at the bait inside the dish.
The dishes were then returned to the lab and
placed in a freezer for 48 h, and all the ants were
counted and identified.
Data were analyzed by analysis of variance. To
normalize counts and equalize variances before
analysis, insect counts (number of adults per tree
and number of egg masses per tree) were trans-
formed by natural log (x + 1). Means were com-
pared by Fisher's protected least significant dif-
ference (LSD) or Tukey's honestly significant dif-
ference test after a significant F-test at a = 0.05
(StatView version 5.0, SAS Institute, Cary, NC,
USA). Although tests of significance were based
on transformed data, only untransformed data
are presented. At the Central Ridge site, the dif-
ferences in the 10 pairs of trunk area measure-
ments were compared using a t-test of the null hy-
pothesis that the mean difference is 0.0 (Minitab
version 13.1, Minitab Inc., State College, PA,
USA).

RESULTS

East Coast Flatwoods Site

The effect of treatment on tree growth was sig-
nificant. At the end of the third year, the rootstock
portion of trees with the Lumite and the Weed-X
fabrics weighed 1.7 and 1.2 times, respectively,
the weight of the rootstock portion of the control
treatment (P = 0.10; Fig. 1A). Similarly, the scion
portion of trees with the Lumite and the Weed-X
fabrics weighed 2.4 and 1.4 times, respectively,
the weight of the scion portion of the control treat-
ment (P = 0.02; Fig. 1B)
No differences were observed throughout the
3-year study in the number of adult weevils on
trees in the 3 treatments (ANOVA, a = 0.05). Lar-


March 2009







Duncan et al.: Landscape Fabric to Manage Diaprepes Root Weevil


600

500

ci 400

S300
JR

8 200

100

0

1200

1000-

2, 800-

l0oGo o





0-


A.

-0- Bare soil
-*- Lumite
--- Dalen


2001 2002 2003

Fig. 1. The effects of Lumite 994GC, and Dalen
Weed-X landscape fabrics on the growth of citrus tree
rootstocks (A) and scions (B) during 3 yr at a infested by
Diaprepes abbreviatus on Florida's east coast. Signifi-
cant differences in means as determined by Tukey's
Honestly Significant Difference Test are denoted by *
(P < 0.05).


vae were difficult to recover from the Winder soil
due to compaction and texture typical of this for-
mation. On average, fewer than 1 larva was recov-
ered per tree despite considerable scarring of
roots. The mean number of larvae recovered per
tree at the end of the third year did not differ be-
tween treatments (ANOVA, a = 0.05) although
there was a trend towards fewer larvae in the Lu-
mite product (0.33 0.11 larvae/tree) compared
with the Weed-X (0.90 0.55) and the control
(0.61 0.40).
The Lumite fabric remained largely intact
through the 3 growing seasons at the flatwoods
site. The Weed-X fabric became more susceptible
to tears over time and many perforations of vary-
ing sizes were observed at the end of the 3-year
trial. Most notably, these included shotgun-like
patterns of holes produced by the red imported
fire ant Solenopsis invicta Buren that constructed
mounds below, through, and above the Weed-X
fabric. We also observed in the Weed-X fabric, but
not the Lumite fabric, what may have been exit


holes produced by emerging adult D. abbreviatus,
but we could not confirm the origin of the holes.

Central Ridge and Central Flatwoods Sites

Trees in mulched plots on the Central Ridge
were larger (P 0.05) than those in bare soil
within 8 months of imposing the treatments (Fig.
2A). After 5 years of growth, the mean cross sec-
tional trunk area of trees growing in mulched soil
was 31% greater (P < 0.02) than that of trees
growing in bare soil. There was a location effect on
trunk size. Differences were small in the 5 treat-
ment pairs at higher elevation, but increased
with decreasing elevation in the remaining treat-
ment pairs (data not shown). Average trunk size
was not affected by elevation for trees in mulched
plots, but trunk size of trees in bare plots was di-
rectly related to elevation.
Significantly fewer D. abbreviatus and A.
floridanus weevils were recovered from ground
traps adjacent to young trees growing in
mulched soil compared to trees growing in bare
soil (Fig. 2, inset). During 17 months, 219 adult
A. floridanus were trapped at the experimental
site, compared to just 12 adult D. abbreviatus.
In contrast, 258 adult D. abbreviatus were
trapped beneath the tree canopies during 4
months at the Central Flatwoods site. The
mean ( SEM) number of weevils trapped per
plot in bare soil (32.1 12.4) was greater (P <
0.001) than that from mulched plots (0.125
0.125; i.e., just 1 weevil). The average number
of weevils trapped at the edges of the mulched


4- 3000
E
E
a

E 2000
ti
.2
Uon


U ,T ,r1I ,,,,,,,T,,Tr l TI ,Tr, ,,TT T ,T I,,, ,rl TT ,,,l,


--0- Bare soil i
-*-- Landscape cloth


SNJMMJSNJMMJS
2003 2004


NJMMJSNJMMJ NJMMJSM
2005 2006 2007


Fig. 2. Effects of Lumite 994GC landscape fabric
mulch on the trunk diameter of citrus seedlings at Central
Ridge site during 5 yr and on the numbers of adultArtipus
floridanus and Diaprepes abbreviatus weevils captured in
ground traps during 18 months (inset). Significant differ-
ences in means as determined by t-test for paired compar-
isons are denoted by (P < 0.05) or ** (P < 0.01).


:*







Florida Entomologist 92(1)


plots (2.75 1.01) did not differ (P > 0.05) from
that in bare plots (4.38 1.95). In both treat-
ments, the numbers of weevils recovered on the
tops of beds (3.06 1.05) were six-fold more nu-
merous (P = 0.02) than on the lower, water fur-
row sides of the beds (0.5 0.18).
The ant baiting assay captured 3,739 worker
ants (0 to 281 per dish), which included 3,734 S.
invicta, 4 Dorymyrmex bureni (Trager), and 1
Brachymyrmex obscurior Forel. Fabric mulch im-
paired foraging by ants. An average of 67 9 S. in-
victa were recovered from stations on bare soil,
compared to just 5 2 (P < 0.001) on fabric mulch.

DISCUSSION

Mulching soil with landscape fabric caused
citrus trees to grow larger at sites infested byD.
abbreviatus on Florida's east coast and interior
Central Ridge. Although, we were unable to
demonstrate reduced larval prevalence or feed-
ing damage to roots of mulched trees at the east
coast site, fewer adult weevils emerged from
mulched trees versus those on bare soil at the
Central Ridge site and at a Central Flatwoods
site, which indicates that reduced weevil activ-
ity on the roots of mulched trees could have con-
tributed to these results. Alternatively, tree
growth rates might have responded positively
to elevated soil temperature and/or moisture in
mulched plots, particularly in the cooler and
drier winter-spring months, and the healthier
trees might have been better able to tolerate
root herbivory by weevil larvae. Fabric mulches
have been reported to increase growth and/or
yield of orchard crops such as nectarine (Szewc-
zuk & Gudarowska 2006), cherry (Yin et al.
2007), apple (Merwin et al. 1995; Nielsen et al.
2003) and acid lime and mandarin (Shirgure, et
al. 2003, 2005).
The reduced emergence of adult D. abbrevia-
tus at the Central Ridge and Central Flatwoods
sites could have occurred because fewer neonate
larvae entered the soil and developed to adults
under mulched trees and/or if adult weevils are
unable to chew through the fabric. During 5 years
at the Central Ridge site we found just 1 hole in
the Lumite fabric that was likely caused by an
emerging adult weevil, eitherD. abbreviatus orA.
floridanus. No evidence was detected of adult
emergence from Lumite fabric at the east coast
site. We cannot discount the possibility that
adults move laterally beneath the fabric until
reaching an edge. However, lateral migration of
adults beneath large areas of fabric to the edges
should cause larger numbers to be trapped from
mulched compared to unmulched plots (in which
adults would trapped only if emerging from the
small areas of soil directly beneath a trap) and
this did not occur. Recovery of adults at fabric
edges is unsurprising because D. abbreviatus ovi-


posit on many of the weed species in row middles
and some neonate larvae that fall from the tree
canopy must succeed in migrating to the edge. In-
deed, the relatively narrow width of the mulch at
the east coast site may have allowed neonate lar-
vae to enter soil by falling near or crawling to the
fabric edge. We observed neonate larval behavior
on the fabric mulch at the Central Ridge site in
May. Larvae that were placed on the fabric in full
sun at 1:00 PM ceased moving in less than 1 min.
However, when placed on the fabric at 8:00 AM,
larvae continued to migrate randomly on the fab-
ric for a 30-min observation period. Because D.
abbreviatus larvae eclose and fall from the can-
opy throughout the 24-h d (Stuart et al. 2003),
those falling during the cooler hours of evening
through early morning have a better chance of en-
tering soil by encountering openings of adequate
size on older fabric or by reaching the fabric edge.
Our limited study of ant behavior on fabric mulch
was conducted during mid-day. It would be inter-
esting to see if the behavior differs during the
cooler hours.
Diaprepes population pressure was fundamen-
tally different at the Central Ridge site compared
to the 2 flatwoods sites. Individual ground traps
in bare plots at the Central Flatwoods site caught
adult weevils at a rate more than 300-fold that of
comparable traps at the Central Ridge site. Simi-
larly high adult capture rates have been reported
for the east coast flatwoods site (Bullock et al.
1999). Visible symptoms of damage to citrus trees
at the three sites corresponded to the large differ-
ences in D. abbreviatus population levels, with
much less damage apparent at the Central Ridge
site. Regional variation in predation of weevils by
endemic entomopathogenic nematodes has been
proposed as one factor that modulates regional
variability in D. abbreviatus population size
(Duncan et al. 2003). Despite having fewer wee-
vils and less evident tree decline at the Central
Ridge site, a surprising amount of feeding dam-
age to roots in the crown area and beyond oc-
curred commonly on trees growing adjacent to the
experiment that were removed to initiate new re-
search. Thus, if the fabric mulch reduced recruit-
ment of neonates into soil, lower root herbivory
may have contributed to the increased growth of
trees in the mulched plots.
Research is ongoing at the Central Flatwoods
site to determine whether fabric mulches of suffi-
cient width (>1.5 m on each side of the trunk) can
reduce weevil damage to the root system. How-
ever, even if confirmed, the high initial cost is a
potential detriment to implementing fabric mulch
as a control tactic. The cost of the Lumite fabric to
mulch trees at the rate of 284 trees ha1 is
$2,262.00. At the Central Ridge site, the physical
integrity of the mulch remained excellent for 4
years, but signs of deterioration became evident
mid-way through the 5th year. Annual herbicide


March 2009







Duncan et al.: Landscape Fabric to Manage Diaprepes Root Weevil


savings in mulched orchards would be approxi-
mately $370.00 ha-1 and would equal the fabric
cost only after 6 years. Nevertheless, additional
savings in pesticide and irrigation costs combined
with faster tree growth and higher fruit yields
could make the use of mulch a profitable manage-
ment tactic.

REFERENCES CITED

BULLOCK, R. C., PELOSI, R. R., AND KILLER, E. E. 1999.
Management of citrus root weevils (Coleoptera: Cur-
culionidae) on Florida citrus with soil-applied ento-
mopathoenic nematodes (Nematode: Rhabditida).
Florida Entomol. 82: 1-7.
DUNCAN, L. W., MCCOY, C. W., STANSLY, P. A., GRA-
HAM, J. H., AND MIZELL, R. F. 2001. Estimating the
relative abundance of citrus root weevils with modi-
fied Tedders traps. Environ. Entomol. 30: 939-946.
DUNCAN, L. W., GRAHAM, J. H., DUNN, D. C., ZELLERS,
J., McCOY, C. W., AND NGUYEN, K. 2003. Incidence
of endemic entomopathogenic nematodes following
application ofSteinernema riobrave for control ofDi-
aprepes abbreviatus. J. Nematol. 35:178-186.
DUNCAN, L. W., GRAHAM, J. H., ZELLERS, J., BRIGHT, D.,
DUNN, D. C., EL-BORAI, F. E., AND PORAZINSKA, D. L.
2007. Food web responses to augmenting the ento-
mopathogenic nematodes in bare and animal ma-
nure-mulched soil. J. Nematol. 39:176-189.
FUTCH, S. H., DUNCAN, L. W., AND ZEKRI, M. 2005. Val-
idation of an area-wide extension program to esti-
mate the seasonal abundance of adult citrus root
weevils with un-baited pyramidal traps. Proc. Flori-
da State Hort. Soc. 117: 143-147.
Graham, J. H., Bright, D. B., AND McCoy, C. W. 2003.
Phytophthora-Diaprepes weevil complex: Phytoph-
thora spp. relationships with citrus rootstocks. Plant
Dis. 87: 85-90.
LAPOINTE, S. L., BORCHERT, D. M., AND HALL, D. G.
2007. Effect of low temperature on mortality and
oviposition in conjunction with climate mapping to
predict spread of the root weevil Diaprepes abbrevia-
tus and introduced natural enemies. Environ. Ento-
mol. 36: 73-82.
McCOY, C. W. 1999. Arthropod pests of citrus roots, pp.
149-156 In L. W. Timmer and L. W. Duncan [eds.], Cit-
rus Health Management. APS Press, St. Paul, MN.


MCCOY, C. W., CASTLE, W. S., GRAHAM, J. H., SYVERTS-
EN, J. P., SCHUMANN, A. W., AND STUART, R. J. 2004.
Pesticide suppression of Diaprepes abbreviatus (L.)
(Coleoptera: Curculionidae) promoted differential
growth and survival of "Hamlin" orange trees bud-
ded to five rootstocks in a Phytophthora infested
grove. Proc. Florida State Hort. Soc. 117: 167-173.
MCKENZIE, C. L., LAPOINTE, S. L., AND DUNCAN, L. C.
2001. Landscape fabric as a physical barrier to neo-
nate Diaprepes abbreviatus (Coleoptera: Curculion-
idae). Fla. Entomol. 84: 721-722.
MERWIN, I. A., ROSENBERGER, D. A., ENGLE, C. A., RIST,
D. L., AND FARGIONE, M. 1995. Comparing mulches,
herbicides, and cultivation as orchard groundcover
management systems. HortTechnology 5: 151-158.
NIELSEN, G. H., HOGUE, E. J., FORGE, T., AND NEILSEN,
D. 2003. Mulches and biosolids affect vigor.yield, and
leaf nutrition of fertigated high density apple. Hort-
Science 38: 41-45.
PENA, J. E., ULMER, B., DUNCAN, R., AND MCCOY, C.
2006. Biological control of neotropical citrus root
weevils, pp. 98-99 In IOBC, Memorias IV congress
international de control biologico, May 31-June 2,
2006. Palmira, Colombia: CIAT.
SHIRGURE, P. S., SINGH, S., PANIGRAHI, P., AND SONKAR,
R. K. 2005. Evaluation of mulches for improving
bearing in acid lime. Indian J. Soil Conserv. 33: 62-
66.
SHIRGURE, P. S., SONKAR, R. K., SINGH, S., AND PANI-
GRAHI, P. 2003. Effect of different mulches on soil
moisture conservation, weed reduction, growth and
yield of drip irrigated Nagpur mandarin (Citrus re-
ticulata). Indian J. Agric. Sci. 73: 148-152.
STUART, R. J., JACKSON, I. W., AND MCCOY, C. W. 2003.
Predation on neonate larvae of Diaprepes abbrevia-
tus (Coleoptera: Curculionidae) in Florida citrus:
testing for daily patterns of neonate drop, ant pred-
ators, and chemical repellency. Florida Entomol.
86(1): 61-72.
SZEWCZUK, A., AND GUDAROWSKA, E. 2006. Effects of
mulching in a nectarine orchard in sustainable fruit
production. J. Fruit Ornamental Plant Res. 14: 217-
223.
YIN, X. H., SEAVERT, C. F., TURNER, J., NUNEZ-ELISEA,
R., AND CAHN, H. 2007. Effects of polypropylene
groundcover on soil nutrient availability, sweet cher-
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Science 42: 147-151.







Florida Entomologist 92(1)


March 2009


CYTOLOGICAL ATTRIBUTES OF SPERM BUNDLES UNIQUE TO
F, PROGENY OF IRRADIATED MALE LEPIDOPTERA: RELEVANCE
TO STERILE INSECT TECHNIQUE PROGRAMS


J. E. CARPENTER1, O. G. MARTI', S. L. WEE2' AND D. M. SUCKLING2
1USDA, ARS, Tifton, Georgia, USA

2HortResearch, P.O. Box 51, Lincoln, New Zealand

3Current Address: School of Environmental & Natural Resource Sciences, Faculty of Science & Technology,
National University of Malaysia, Bangi, Malaysia


ABSTRACT

The unique genetic phenomena responsible for inherited F, sterility in Lepidoptera and
some other arthropods provide advantages for the use of inherited sterility in a sterile insect
technique (SIT) program. Lepidopteran females generally can be completely sterilized at a
dose of radiation that only partially sterilizes males of the same species. When these par-
tially sterile males mate with fertile females, many of the radiation-induced deleterious ef-
fects are inherited by the F, generation. At the appropriate dose of radiation, egg hatch of
females mated with irradiated males is reduced and the resulting (F,) offspring are both
highly sterile and predominantly male. Lower doses of radiation used to induce F, sterility
increase the quality and competitiveness of the released insects. However, during a SIT pro-
gram it is possible that traps used to monitor wild moth populations and over-flooding ratios
(marked released males vs unmarked wild males) may capture unmarked F, sterile males
that cannot be distinguished from wild fertile males. In this study we developed a cytological
technique with orcein and Giemsa stains to distinguish adult F, progeny of irradiated males
and fertile males. Our observations on 6 pest species in 5 families of Lepidoptera indicate
that F, males (sterile) from irradiated fathers can be distinguished from fertile males by the
nuclei cluster in the eupyrene sperm bundles. The nuclei cluster in the fertile males exhib-
ited a regular and organized arrangement of the sperm and was homogeneously stained,
whereas in F, males the nuclei cluster of sperm was disorganized, irregular and unevenly
stained.
Supplementary Material: color illustrations are available online at http://www.fcla.edu/
FlaEnt/fe921.htm

Key Words: SIT, inherited sterility, Lepidoptera, eupyrene sperm


RESUME

El fen6meno gen6tico unico responsible para la esterilidad heredada en estado F, de los
lepid6pteros y otros artr6podos provee una ventaja para el uso de la esterilidad heredada
en un program de t6cnica de insecto est6ril (TIE). Las hembras de lepid6pteros gene-
ralmente pueden ser completamente esterilizadas con una dosis de radiaci6n que sola-
mente esteriliza parcialmente los machos de la misma especie. Cuando estos machos
esterilizados parcialmente se aparean con hembras f6rtiles, muchos de los efectos delec-
tivos inducidos por la radiaci6n son heredados por la generaci6n F,. A la dosis de radia-
ci6n apropiada, la eclosi6n de los huevos de las hembras apareadas con machos
irradiados es reducida y las progenies que resultan son altamente est6riles y predomi-
nantemente del sexo macho. Las dosis mas bajas de radiaci6n usada para inducir la es-
terilidad de F, aumentan la calidad y la competividad de los insects liberados. Sin
embargo, durante el program de TIE es possible que las trampas usadas para monito-
rear poblaciones de polillas salvajes y la tasa de sobre liberaci6n machoss liberados mar-
cados versus los machos salvajes no marcados) pueden capturar machos est6riles de F,
no marcados que no pueden ser distinguidos de machos salvajes f6rtiles. En este studio
nosotros desarrollamos una t6cnica citol6gica usando cepas de orcein y Giemsa, lo cual
distingue la progenie F, de los adults machos irradiados y machos f6rtiles. Nuestras ob-
servaciones sobre species de 6 plagas en 5 families del orden Lepid6ptero indican que
los machos F, (est6riles) que provienen de machos irradiados pueden ser distinguidos de
los que provienen de machos f6rtiles por un grupo de nucleos en bultos de esperma eupi-
rene. El grupo de nucleos en los machos f6rtiles presentaron un arreglo de esperma re-







Carpenter et al.: F, Sterile Sperm Bundles


gular y organizado y fue homog6neamente tenido, mientras que en los machos de F,el
grupo de los nmcleos de esperma fue desorganizado, irregular y tenido de una manera
dispareja.


Established and invasive lepidopteran pests
representing numerous taxonomic families are
a major threat to agriculture, forestry, and nat-
ural areas throughout the world (Peters 1987;
Bloem & Carpenter 2001; Bloem et al. 2005). In
response to this threat, industry, communities,
and pest managers continually seek to develop
pest control programs that are economically, en-
vironmentally, and socially acceptable. A com-
mon challenge in this process is the desire to
identify strategies that are species-specific,
broad-based, and portable across several taxo-
nomic families. These apparently divergent fea-
tures often have been bridged by the use of the
sterile insect technique (SIT) in area-wide, inte-
grated pest management programs with goals
including pest suppression, eradication, con-
tainment, and prevention (Hendrichs et al.
2005). The SIT involves mass rearing, steriliza-
tion, and release of sterile pest insects to mate
with feral insects, and is therefore species spe-
cific. SIT is a broad-based tactic because it is
currently, or recently has been, used in pro-
grams targeting tortricid, gelechiid, lymantriid,
and pyralid pests of row crops, orchards, forests
and natural areas, respectively (Bloem et al.
2007; Carpenter et al. 2007; Suckling et al.
2007; Henneberry 2007).
The current method of choice in SIT pro-
grams for rendering insects reproductively ster-
ile is exposure to ionizing radiation (Bakri et al.
2005). Selection of the most appropriate dose of
radiation is important because quality and per-
formance of the released insect often are re-
duced as the dose of radiation increases
(Calkins & Parker 2005). In Lepidoptera, fe-
males can be completely sterilized at a dose of
radiation that only partially sterilizes males of
the same species. However, when these par-
tially sterile males mate with fertile females,
many of the radiation-induced deleterious ef-
fects are inherited by the F, generation. At the
appropriate dose of radiation, egg hatch of the
females mated with the irradiated males is re-
duced and the resulting (F,) offspring are both
sterile and predominantly male (Carpenter et
al. 2005). The unique attributes of F, sterility
(also referred to as inherited sterility) have
been reported for all lepidopteran species exam-
ined (LaChance 1985).
Reproductively sterile moths released dur-
ing a SIT program often are marked with an in-
ternal or external dye so that they may be dis-
tinguished from wild moths. Marking tech-
niques are used in field monitoring of sterile to
wild ratios, measuring performance of released


moths, and determining the sensitivity of trap-
ping grids used to confirm eradication (Kean &
Suckling 2005). Reliable methods to distinguish
released moths from wild moths mitigate the
chance that a released moth may be misidenti-
fied as a wild moth, possibly leading to huge fi-
nancial consequences for an area-wide IPM
eradication program (Parker 2005). Because
the appropriate dose of radiation for maintain-
ing high quality moths for release permits the
development of unmarked F, sterile moths in
the field, it is possible that both unmarked F,
sterile males and wild fertile males may be cap-
tured in traps. Concerns about the use of F ste-
rility include the erroneous view that the pro-
duction of sterile F, larvae will cause economic
damage to crops, especially in high-value crops
such as fruit, and that F, sterile moths will be
misidentified as wild moths and lead to expen-
sive, yet unnecessary, interventions. Use of F,
sterility makes it difficult to accurately esti-
mate the wild population and the over-flooding
ratio with traps because both wild males and
sterile F, males are unmarked. A suitable
method for distinguishing wild males and ster-
ile F, males would avoid these concerns and
would provide a positive feedback that irradi-
ated males released in the field were mating
with wild females.
Tothova & Marec (2001) demonstrated that
various types of radiation-induced transloca-
tions are responsible for the production of ge-
netically unbalanced gametes in F, progeny of
irradiated moths and represent the main chro-
mosomal mechanism of F, sterility. Several au-
thors have reported the effects of radiation on
the incidence of visible chromosomal aberra-
tions in F, male larvae that were detected with
light microscopy (Carpenter et al. 2005), and
North & Snow (1978) and Carpenter & Gross
(1993) used the incidence of chromosomal aber-
rations in field-collected larvae as verification
that irradiated/released males had mated with
wild females. These chromosome translocations
make successful meiotic divisions impossible,
resulting in genetically unbalanced gametes
(Tothova & Marec 2001; Carpenter et al. 2005).
Because the primary spermatocytes in a cyst
undergo two meiotic divisions leading to the for-
mation of a sperm bundle containing four sperm
for each spermatocyte, we surmised there
would be an unbalanced amount of chromatin
material among the sperm nuclei within eu-
pyrene sperm bundles from an F, sterile male
moth. We examined the homogeneity of chroma-
tin material in the nuclei cluster of eupyrene







Florida Entomologist 92(1)


sperm bundles to determine if there were differ-
ences between fertile and F, sterile males. Our
goal was to identify a characteristic that can be
used to accurately categorize wild males and
sterile F, males captured in traps, regardless of
age, mating status, and taxonomic family.

MATERIALS AND METHODS

Sources of Insects

Six lepidopteran species examined in this
study included codling moth (Cydia pomonella
L., Tortricidae), obtained from the Okanagan
Kootenay-Sterile Insect Release rearing facility
in British Columbia, Canada; South American
cactus moth (Cactoblastis cactorum (Berg),
Pyralidae), obtained from the colony reared at
the USDA, ARS, Crop Protection and Manage-
ment Research Unit (CPMRU) insectary, Tifton,
GA; diamondback moth (Plutella xylostella L.,
Plutellidae), obtained from the CPMRU colony;
painted apple moth (Teia anartoides Walker,
Lymantriidae), examined by authors DMS and
SLW in New Zealand because of quarantine re-
strictions on transport of this Australian spe-
cies to the US; corn earworm (Helicoverpa zea
(Boddie), Noctuidae), obtained from the
CRMRU colony, and fall armyworm
(Spodoptera frugiperda J. E. Smith, Noctuidae),
from the CPMRU colony.

Irradiation

In each species, newly emerged males less
than 24 h old were exposed to 150 Gy of gamma
radiation from a 60Co source except for painted ap-
ple moth, which was exposed to 100 Gy at the late
pupal stage. Similar males were not irradiated
and their progeny served as controls. Irradiated
and control males were caged individually with
unirradiated conspecific females, eggs were col-
lected from the mated pairs, and the larvae were
reared on the appropriate diet in the laboratory.
F, males were dissected and smears of sperm bun-
dles were prepared from the seminal vesicles and
testes.

Dissection of Moths

Moths were killed by immersion in 70-95%
ethanol for a few seconds, rinsed and dissected
in tap water in a small Petri dish. Insect saline
solution may be used for the dissection instead
of water, but we found no advantage in using it.
In addition, saline forms crystals on the slide,
interfering with staining and requiring an ex-
tra step for removal.


The posterior abdomen just above the clasp-
ers of the freshly killed moth was pulled with a
pair of fine forceps until most of the simplex was
exposed. This procedure will pull the duplex,
vasa deferentia, seminal vesicles, and testes to
the posterior abdomen, where they can be more
easily dissected free from adhering fat body and
tracheal tubules. Because there is a daily
rhythm in the descent of mature sperm bundles
from the testes to the seminal vesicles and then
to the duplex for lepidopteran species (Riemann
et al. 1974, Seth et al. 2002), the relative abun-
dance of sperm bundles through out the repro-
ductive tract varies by species and the photope-
riod at the time of dissection or male death.
Therefore, it is advisable to examine the duplex,
vasa deferentia, seminal vesicles, and testes in
the development of the best protocol for each
species.
Seminal vesicles, duplex, and testes can be
smeared separately on the same slide. The 2
testes are enclosed within a single membrane
and can be treated as a single structure. Each
part of the reproductive tract can be opened
with help of fine forceps and the contents agi-
tated in a very small drop of water on the slide
until the sperm bundles are freed from the sur-
rounding secretions. They are readily visible on
a stereoscope under low magnification (30x).
Smears may be allowed to dry for several hours,
or overnight, or for a few minutes on a hot plate
(~600C).

Staining of Slides

For tissue fixation, slides containing smears
were placed on a staining rack over a sink and
flooded with absolute methanol for 5 min. The
slides were then drained of methanol and allowed
to dry before staining with aceto-orcein stain for 5
min. The stain was prepared by adding 4.0 g of
synthetic orcein to 80 mL of glacial acetic acid in
80 mL of distilled water. The solution was boiled
for 5 min, filtered, allowed to stand overnight, and
filtered again. Then 40 mL of acetic acid were
added drop-wise while stirring to dissolve any
precipitate. Finally, 20 drops of glycerol were
added to the solution (White 1973). The stained
slides were rinsed in running tap water for 10 s
and allowed to dry. The dried slides were stained
with freshly prepared Giemsa stain. The Giemsa
stain was prepared by mixing Giemsa stock with
phosphate buffer (pH 7.41) at 1:1 (v/v) ratio.
Slides may be stained from 30 min to 2 h to obtain
good results. Slides were then rinsed in running
tap water for 30 s, allowed to dry completely,
rinsed for 5 s in absolute ethanol, and allowed to
dry again before being mounted with Permount or
other mounting medium.
Sperm nuclei in intact bundles of some species,
particularly H. zea, were frequently non-respon-


March 2009







Carpenter et al.: F, Sterile Sperm Bundles


sive to the staining procedure described above. In
this case, before staining the slides with aceto-or-
cein, they were hydrolyzed with 1 M HC1 for 2-5
min at 60C on a hot plate and then stained satis-
factorily. However, the intensity of subsequent Gi-
emsa staining is progressively fainter after more
than 5 min of hydrolysis. After treatment with
HC1, the slides were rinsed in running tap water
for 5 s and dried before staining with the aceto-or-
cein and Giemsa stains, as described above.
Each of the steps above can be varied depend-
ing on species and the procedures should be
adapted to produce satisfactory staining results.
The proportions of stain: buffer can be varied
from 1:1 to 1:9, with consistently good, but vari-
able results, as can the pH of the buffer, ranging
from pH 4.0 to 10.0. In general, variations in the
proportions of the stain:buffer and/or the pH of
the buffer will produce variations in color of the
stained tissues, usually from predominantly red
to predominantly blue. Omitting the orcein step
produced slides that were too blue, and omitting
the Giemsa step produced slides that were too
red. Using both stains produced slides with the
best contrast and color; therefore, we recommend
the use of both stains. Stained slides of control
and irradiated F, individuals were studied and
compared at low and high magnification (200x
and 400x) on a Nikon Optiphot compound micro-
scope.

RESULTS AND DISCUSSION

In the testes and seminal vesicles, consistent
and obvious differences were observed in individ-
ual sperm nuclei of eupyrene sperm bundles be-
tween the control (fertile) and F, (sterile) males.
In control males of all species we examined, the
sperm nuclei in the eupyrene sperm bundles are
usually clustered and arranged in an orderly
manner with the anterior ends of individual
sperm usually equidistant from the anterior end
of the sperm bundle (Fig. 1, A-D and Fig. 2, A-C).
Even in poorly stained slides, the consistent or-
derly arrangement of individual sperm nuclei at
the anterior end of the bundle is an obvious indi-
cator that the preparation was from a fertile
moth. The nuclei cluster of the eupyrene sperm
bundles of normal males was stained homoge-
neously, indicating that equal amounts of chro-
matin material were present in each sperm.
In contrast, individual sperm nuclei in eu-
pyrene sperm bundles from F, sterile moths were
irregularly arranged and irregularly stained pat-
terns were consistently observed, often with only
a few or a low fraction of sperm nuclei in the bun-
dle being stained (Fig. 1, E-H and Fig. 2, D-H).
This heterogeneously stained nuclei cluster re-
vealed that the amount of chromatin material in
each sperm nucleus of F, sterile males was highly
variable and disorganized compared with controls


of the same species. Variations in the nuclear
staining patterns were often great because some
sperm within a bundle had no visible evidence of
chromatin material while other sperm within the
same bundle exhibited abnormally high levels of
chromatin material. These cytological character-
istics, observed in all males examined, are consis-
tent with the findings of Tothova & Marec (2001)
who showed that various types of chromosomal
translocations produce genetically unbalanced
gametes in F, progeny of irradiated parents.
In well-stained preparations, the distinction
between the 2 treatments is often immediately
apparent. However, in the process of developing
the staining procedures in this study, inade-
quately stained slides were frequently produced.
For evaluation purpose, it was necessary to dis-
tinguish between a poorly-stained smear from a
normal moth and a preparation from an F, sterile
moth. In this case, familiarity with the character-
istics of the sperm bundles of the species under in-
vestigation, the application of a satisfactory
staining procedure, and a thorough scan of each
slide should allow a rapid and consistently accu-
rate determination of the status of each moth ex-
amined. As a precaution, extra smears from the
same individual could be prepared on separate
slides in case the first stained slide cannot be con-
fidently scored. In addition, a set of slides for each
species should be produced for future reference, if
necessary. Because all the sperm bundles within a
male moth will be either normal (i.e., from a fer-
tile male) or abnormal (i.e., from F, sterile male)
and thus fall into a simple 'all-or-none' category,
there is no need for a statistical analysis for sta-
tus determination of the moths tested.
The best slides were those smears obtained
from freshly killed moths. Unsatisfactory results
were produced with frozen or ethanol-preserved
moths. However, moths that appeared to be dead
but still fully hydrated could have eupyrene
sperm bundles that are responsive to the staining
procedures (Wee et al. unpublished data). Inten-
sity of staining and the overall quality of a smear
preparation in certain species can be improved by
acid hydrolysis (Fig. 1C). Unstained slides, previ-
ously fixed with absolute methanol, can be stored
for at least 1 month for later staining (Wee et al.
unpublished data). The species used in this inves-
tigation representing 5 lepidopteran families var-
ied in size from the small diamondback moth, P.
xylostella (~1.2 cm wingspan) to the larger corn
earworm, H. zea (~4.0 cm wingspan). Similarly,
the mature sperm bundles of these species varied
in shape, length, and staining characteristics.
Nevertheless, this technique worked well for all
species examined.
As an overall conclusion, our observations in-
dicate that F, males (sterile) from irradiated fa-
thers can be distinguished from fertile males
based on the homogeneity of staining in the nuclei






Florida Entomologist 92(1)


*t


Fig. 1. A-D: Codling moth, Cydia pomonella. A and C: sperm bundles from testis smears of normal males, B and
D: sperm bundles from testis smears of sterile F, males (progeny of irradiated males mated with normal females). E-
F: Fall armyworm, Spodoptera frugiperda, E: normal male, sperm bundles from testis smear hydrolyzed in 1 M HC1,
F: sperm bundles from sterile F, male. G-H: Corn earworm, Helicoverpa zea, G: sperm bundles from testis smear of
normal male, H: sperm bundles from testis smear of sterile F, male. In all normal males, nuclei clusters of the eu-
pyrene sperm bundles were homogenously stained but were heterogeneously stained in the sterile F, males.


March 2009





Carpenter et al.: F1 Sterile Sperm Bundles


a

E.
.-.


k)
I


I (r-


K;


J .


4'~


Fig. 2. A-B: Painted apple moth, Teia anartoides, A: sperm bundles from seminal vesicle smear of normal male,
B: sperm bundles from seminal vesicle smear of sterile F, male (progeny of irradiated male mated with normal fe-
male). C-D and F: cactus moth, Cactoblastis cactorum, C: sperm bundles from testis smear of normal male, D and
F: sperm bundles from testis smear of sterile F, males. E and G-H: Diamondback moth, Plutella xylostella, E: sperm
bundle from testis smear of normal male, G-H: sperm bundles from testis smears of sterile F, males. In all normal
males, nuclei clusters of the eupyrene sperm bundles were homogenously stained but were heterogeneously stained
in the sterile F, males.


5^,











cluster of the eupyrene sperm bundles. Because
this technique uses cytological attributes of the
nuclei of sperm bundles in the testes, it cannot be
affected by the age nor mating status of the male
specimen to be evaluated. Although this tech-
nique has limited use on dead moths, it is the only
method that could directly determine the origin/
history of the trapped moth in a SIT sterile moth
release program. This technique will be a great
asset and potentially be adaptable for all lepi-
dopteran pests involved in future SIT programs.


ACKNOWLEDGMENT

We gratefully acknowledge the Okanagan-Kootenay
Sterile Insect Release Program, British Columbia, Can-
ada, for providing us with fertile and F, sterile codling
moths. The contributions of DMS and SLW were funded
by the New Zealand Ministry of Agriculture and For-
estry and the Foundation for Research Science and
Technology investment in "Better Border Biosecurity"
(www.b3nz.org).


REFERENCES CITED

BAKRI, A., MEHTA, K., AND LANCE, D. R. 2005. Steriliz-
ing insects with ionizing radiation, pp. 233-268 In V.
A. Dyck, J. Hendrichs, and A. S. Robinson [eds.],
Principles and Practice in Area-Wide Integrated
Pest Management. Springer, Dordrecht, The Nether-
lands.
BLOEM, S., AND CARPENTER, J. E. 2001. Evaluation of
population suppression by irradiated Lepidoptera
and their progeny. Florida Entomol. 84: 165-171.
BLOEM, K. A., BLOEM, S., AND CARPENTER, J. E. 2005.
Impact of moth suppression/eradication pro-
grammes using the sterile insect technique or inher-
ited sterility, pp. 677-700 In V. A. Dyck, J. Hendrichs,
and A. S. Robinson [eds.], Principles and Practice in
Area-Wide Integrated Pest Management. Springer,
Dordrecht, The Netherlands.
BLOEM, K., BLOEM, S., CARPENTER, J., HIGHT, S.,
FLOYD, J., AND ZIMMERMANN, H. 2007. Don't Let
Cacto Blast Us: Development of a Bi-National Plan
to Stop the Spread of the Cactus Moth Cactoblastis
cactorum in North America, pp. 337-344 In M. J. B.
Vreysen, A. S. Robinson, and J. Hendrichs [eds.], Ar-
ea-Wide Control of Insect Pests From Research to
Field Implementation. Springer, Dordrecht, The
Netherlands.
CALKINS, C. O., AND PARKER, A. G. 2005. Sterile insect
quality, pp. 269-296 In V. A. Dyck, J. Hendrich, and
A. S. Robinson [eds.], Principles and Practice in Ar-
ea-Wide Integrated Pest Management. Springer,
Dordrecht, The Netherlands.
CARPENTER, J. E., BLOEM, S., AND MAREC, F. 2005. In-
herited sterility in insects, pp. 115-146 In V. A. Dyck,
J. Hendrichs and A. S. Robinson [eds.], Principles
and Practice in Area-Wide Integrated Pest Manage-
ment. Springer, Dordrecht, The Netherlands.
CARPENTER, J. E., AND GROSS, H. R. 1993. Suppression
of feral Helicoverpa zea (Lepidoptera: Noctuidae)
populations following the infusion of inherited steril-
ity from released substerile males. Environ. Ento-
mol. 22: 1084-1091.


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CARPENTER, J. E., BLOEM, S., AND HOFMEYR, H. 2007.
Area-Wide Control Tactics for the False Codling
Moth Thaumatotibia leucotreta in South Africa: a
Potential Invasive Species, pp. 351-359 In M. J. B.
Vreysen, A. S. Robinson, and J. Hendrichs [eds.], Ar-
ea-Wide Control of Insect Pests From Research to
Field Implementation. Springer, Dordrecht, The
Netherlands.
HENDRICHS, J., VREYSEN, M. J. B., ENKERLIN, W. R.,
AND CAYOL, J. P. 2005. Strategic options in using
sterile insects for area-wide integrated pest manage-
ment, pp. 563-600 In V. A. Dyck, J. Hendrichs, and A.
S. Robinson [eds.], Principles and Practice in Area-
Wide Integrated Pest Management. Springer, Dor-
drecht, The Netherlands.
HENNEBERRY, T. J. 2007. Integrated Systems for Control
of the Pink Bollworm Pectinophora gossypiella in
Cotton, pp. 567-579 In M. . Vreysen, A. S. Robin-
son, and J. Hendrichs [eds.], Area-Wide Control of
Insect Pests From Research to Field Implementa-
tion. Springer, Dordrecht, The Netherlands.
KEAN, J. M., AND SUCKLING, D. M. 2005. Estimating the
probability of eradication of painted apple moth from
Auckland. New Zealand Plant Prot. 58: 7-11.
LACHANCE, L. E. 1985. Genetic Methods for the Control
of Lepidopteran Species: Status and Potential, ARS-
28. USDA-ARS, Washington, DC.
MARTI, O. G., AND CARPENTER, J. E. 2007. A character
demonstrating the occurrence of mating in male
Cactoblastis cactorum (Lepidoptera: Pyralidae).
Florida Entomol. 90: 278-281.
NORTH, D. T., AND SNOW, J. W. 1978. Recovery of chro-
mosome aberrations from natural populations of
corn earworms and tobacco budworms subjected to
daily releases of partially sterile moths. J. Econ. En-
tomol. 71: 358-360.
PARKER, A. G. 2005. Mass-rearing for sterile insect re-
lease, pp. 209- 232 In V. A. Dyck, J. Hendrichs, and A.
S. Robinson [eds.], Principles and Practice in Area-
Wide Integrated Pest Management. Springer, Dor-
drecht, The Netherlands.
PETERS, T. M. 1987. Negative insect-human interac-
tions, pp. 223-292 In Insects and Human Society.
AVI Book, Van Nostrand Reinhold Co., New York.
RIEMANN, J. G., THORSON, B. J., AND RUUD, R. L. 1974.
Daily cycles of release of sperm from the testis of the
Mediterranean flour moth. J. Insect Physiol. 20: 195-
207.
SETH, R. K., RAO, D. K., AND REYNOLDS, S. E. 2002.
Movement of spermatozoa in the reproductive tract
of adult male Spodoptera litura: daily rhythm on
sperm descent and the effect of light regime on male
reproduction. J. Insect Physiol. 48: 119-131.
SUCKLING, D. M., BARRINGTON, A. M., CHHAGAN, A.,
STEPHENS, A. E. A., BURNIP, G. M., CHARLES, J. G.,
AND WEE, S. L. 2007. Eradication of the Australian
Painted Apple Moth Teia anartoides in New Zealand:
Trapping, Inherited Sterility, and Male Competitive-
ness, pp. 603-615 In M. J. B. Vreysen, A. S. Robinson,
and J. Hendrichs [eds.], Area-Wide Control of Insect
Pests From Research to Field Implementation.
Springer, Dordrecht, The Netherlands.
TOTHOVA, A., AND MAREC, F. 2001. Chromosomal prin-
ciple of radiation-induced F, sterility in Ephestia
kuehniella (Lepidoptera: Pyralidae). Genome 44:
172-184.
WHITE, M. J. D. 1973. Animal Cytology and Evolution.
Third edition. University Press, Cambridge.


Florida Entomologist 92(1)










Plate 1


Fig 1. A-D: Codling moth, Cydiapomonella. A and C: sperm bundles from testis smears of

normal males, B and D: sperm bundles from testis smears of sterile Fi males (progeny of

irradiated males mated with normal females). E-F: Fall armyworm, Spodopterafrugiperda, E:

normal male, sperm bundles from testis smear hydrolyzed in 1 M HC1, F: sperm bundles from

sterile Fi male. G-H: Corn earworm, Helicoverpa zea, G: sperm bundles from testis smear of

normal male, H: sperm bundles from testis smear of sterile Fi male. In all normal males, nuclei

clusters of the eupyrene sperm bundles were homogenously stained but were heterogeneously

stained in the sterile Fi males.











































Fig 2. A-B: Painted apple moth, Teia anartoides, A: sperm bundles from seminal vesicle smear

of normal male, B: sperm bundles from seminal vesicle smear of sterile Fi male (progeny of

irradiated male mated with normal female). C-D and F: cactus moth, Cactoblastis cactorum, C:

sperm bundles from testis smear of normal male, D and F: sperm bundles from testis smear of

sterile Fi males. E and G-H: Diamondback moth, Plutella xylostella, E: sperm bundle from testis

smear of normal male, G-H: sperm bundles from testis smears of sterile Fi males. In all normal

males, nuclei clusters of the eupyrene sperm bundles were homogenously stained but were

heterogeneously stained in the sterile Fi males.







Lee: A New Cicada in the Genus Dilobopyga


DESCRIPTION OF A NEW CICADA IN THE GENUS DILOBOPYGA
(HEMIPTERA: CICADIDAE)

YOUNG JUNE LEE
University of Connecticut, Department of Ecology and Evolutionary Biology, 75 North Eagleville Road,
Storrs, CT 06269, USA

ABSTRACT

A new cicada species, Dilobopyga aprina Lee, sp. nov. from Sulawesi is described. This new
species is distinguishable from its congeners by the presence of 2 pairs of transverse black
spots on the abdominal tergite 3 and the absence of such spots on other tergites and by the
unique shape of the upper lobes of pygofer and the long and pointed claspers in the male gen-
italia.

Key Words: taxonomy, Dilobopyga aprina, Sulawesi, Cicadidni, Cosmopsaltriina

RESUME

Se describe una nueva especie de cigarra, T, .. -*. -. ..r aprina Lee, sp. nov. de Sulawesi. Se
distingue esta nueva especie de sus cong6neres por la presencia de 2 pares de manchas ne-
gras transversales sobre el terguito 3 del abdomen y por la ausencia de estas manchas sobre
los otros terguitos y por la forma distinta de los 16bulos superiores del pigofer y por las pinzas
largas y agudas de la genitalia del macho.


The genus Dilobopyga Duffels was erected by
Duffels (1977) with Dilobopyga chlorogaster
(Boisduval) as the type species. This genus be-
longs to the subtribe Cosmopsaltriina of the
tribe Cicadini in the subfamily Cicadinae, fol-
lowing the classification of Lee (2008). According
to Moulds' classification (2005), the Cosmopsal-
triina belongs to the tribe Dundubiini, treating
Cicadini as a sister group of the Dundubiini, but
the genera of the 4 subtribes of Cicadini-Cica-
dina, Cosmopsaltriina, Dundubiina, and Tosen-
ina-have many common morphological at-
tributes and are thought to be hardly separable
at tribal level.
Twelve species have been described so far in
the genus Dilobopyga: D. chlorogaster (Boisduval,
1835), D. margarethae Duffels, 1977 (with 2 sub-
species), D. gemina (Distant, 1888a) (with 2 sub-
species), D. ornaticeps (Breddin, 1901), D. multi-
signata (Breddin, 1901), D. minahassae (Distant,
1888b), D. opercularis (Walker, 1858), D. breddini
(Duffels, 1970), D. similis Duffels, 1977, D. alfura
(Breddin, 1900),D.janstocki Duffels, 1990, and D.
remanei Duffels, 1999.
A key to 10 species of Dilobopyga was provided
by Duffels (1977). In later years, Duffels (1990,
1999) described 2 more species: D. janstocki and
D. remanei.
This paper presents the description of a new
species of Dilobopyga from Sulawesi, which was
found in the collections of the Korea National Ar-
boretum, Pocheon, Korea (KNAM). Morphological
measurements were made with Vernier calipers.
Morphological terminology follows that of Moulds
(2005).


Description of a New Species

,I.. '. -!.*.. ., aprina Lee, sp. nov., (Figs. 1-3)

Type Material. Holotype: male (Fig. 1), "Sam-
puraga, // Sulawesi, Indonesia // VII. 1997 // Coll.
Young June LEE" (printed white label) (KNAM).
Paratypes: 3 males and 1 female, same data as ho-
lotype (KNAM).
Er ...I. ...,. The specific name, aprina, means
'of a wild boar' in reference to the fact that the lat-
eral view of the male pygofer reminds the author
of the head of a pig.
Measurements of Types (in mm, 4 males or 1 fe-
male). Length of body: male 33.5 (32.1-35.1), fe-
male 26.6; length of fore wing: male 45.4 (44.1-
46.1), female 44.8; width of fore wing: male 13.6
(13.4-13.9), female 13.7; length of head: male 3.8
(3.7-3.9), female 4.0; width of head including eyes:
male 10.4 (10.2-10.7), female 10.6; width of prono-
tum: male 11.5 (11.3-11.7), female 11.1; width of
mesonotum: male 9.9 (9.6-10.2), female 9.9; wing
span: male 99.5 (97.5-101.9), female 96.2.
Diagnosis. This new species is distinguishable
from any of the described species ofDilobopyga by
the presence of 2 pairs of transverse black spots
on the abdominal tergite 3 of male and the ab-
sence of such spots on other tergites. In the male
genitalia, this species can be distinguished by the
upper lobes of pygofer in lateral view, which are
angulated twice on lower side and by the long and
pointed claspers.
Description of Male (Fig. 1). Ratio of body
length to head width about 3.20 (3.05-3.38). Head
ochraceous with the following black to fuscous







Florida Entomologist 92(1)


Fig. 1. 1..1-.-...o....- aprina Lee, sp. nov., holotype, male, Sampuraga, Sulawesi, Indonesia, VII-1997. A. dorsal
view. B. ventral view.


markings: a median large spot enclosing ocelli, of
which anterior end reaching frontoclypeal suture;
a pair of large spots on both sides of the median
spot, which are similar-sized with the median
spot, separated from the median spot by grooves,
and of which lateral ends reaching compound
eyes; and sometimes a pair of tiny spots on sides
of lateral ocelli. Distance between lateral ocelli
and compound eyes about as wide as or slightly
wider than twice distance between 2 lateral ocelli.
Postclypeus slightly swollen. Antennae dark
brown. Ventral part of head ochraceous with black
to fuscous markings. Postclypeus with fasciae
along anterior 5 transverse grooves, a median lon-
gitudinal fascia of which anterior part divided
into 2 parts, and a transverse fascia along poste-
rior margin. Anteclypeus with a pair of oblique el-


liptic spots on about posterior V2 to 23. Rostrum
black to fuscous apically; passing center or poste-
rior margin of sternite II. Lorum margined with
black to fuscous except about anterior 14. Gena
with a transverse fascia between postclypeus and
compound eye, of which inner end touching post-
clypeus but outer end not touching compound eye.
Pronotum ochraceous. Inner area of pronotum
with a pair of central longitudinal fasciae, extend-
ing from anterior margin of pronotum to pronotal
collar and dilated both anteriorly and posteriorly,
a pair of short, oblique branches from middle of
the central longitudinal fasciae along paramed-
ian fissures, a pair of fasciae along lateral fis-
sures, of which anterior end broadened, and a pair
of curved fasciae along lateral margin of inner
area, black to fuscous. Pronotal collar without


A B


Fig. 2. Dilobopyga aprina Lee, sp. nov., paratype, female, Sampuraga, Sulawesi, Indonesia, VII-1997. A. dorsal
view. B. ventral view.


March 2009


t~c
~--~


z---







Lee: A New Cicada in the Genus Dilobopyga


A B

C D


4


Fig. 3. Male pygofer of 1,-..-/-..i.. ... aprina Lee, sp.
nov. A. ventral view. B. lateral view. C. ventral view of
aedeagus. D. lateral view of aedeagus.


markings. Anterolateral pronotal collar slightly
developed and dentate.
Mesonotum ochraceous with a median longitu-
dinal fascia broadened at posterior 13, a pair of
small roundish spots enclosing scutal depressions,
a pair of inwardly curved fasciae along parapsidal
sutures, and 2 pairs of longitudinally arranged
curved fasciae on lateral sigilla, of which posterior
one longer, black to fuscous. Cruciform elevation
ochraceous with fuscous posterior margin medi-
ally. Posterior mesonotum and cruciform elevation
irregularly covered with white pollinosity. Ventral
part of thorax ochraceous.
Legs ochraceous. Fore femur with a small sub-
apical spine as well as primary and secondary
spines; fuscous apically and basally and on
spines. Fore and mid pretarsi mostly fuscous. Mid
and hind tibiae apically fuscous. Fore, mid, and
hind pretarsal claws mostly fuscous.
Wings hyaline. Fore wing with an infuscation
on radial, radiomedial, and sometimes indis-
tinctly medial crossveins. Venation dark brown in
fore wing, ochraceous in hind wing. Basal cell
tinged with ochraceous. Basal membrane whitish
gray but sometimes tinged with brown. Hind
wing jugum whitish gray.
Operculum pale ochraceous very narrowly mar-
gined with black on about basal 13 of lateral margin;
long, gradually narrowed to rounded tip, passing
posterior margin of sternite VI. Lateral margin of
operculum weakly sinuate at base. Basal /4 of inner
margin a little concave. Two opercula nearly touch-
ing each other in the middle.


Abdomen obconical, longer than distance from
head to cruciform elevation. Abdomen ochraceous
with black to fuscous markings; irregularly cov-
ered with white pollinosity on tergites 1-5 and 8.
Tergite 2 with tiny median spot on anterior mar-
gin. Tergite 3 with tiny median spot on anterior
margin and 2 pairs of spots transversely arranged
along posterior submargin, of which paramedian
ones larger than lateral ones. Tergites 4 and 5
each with a pair of lateral spots. Tergites 6 and 7
each with a transverse fascia along anterior mar-
gin and a pair of lateral spots, often the fascia and
the spots fused with each other in tergite 7. Terg-
ite 8 with irregularly fuscous anterior margin.
Posterior margin of tergite 3 wider than anterior
margin of mesonotum. Timbal cover grayish
ochraceous, quarter round or semicircular. Tim-
bal concealed with timbal cover in dorsal view.
Ventral part of abdomen ochraceous. Sternite II
with fuscous transverse fascia in the middle. Ster-
nite VII fuscous on anterior 2 to 23.
Male Genitalia (Fig. 3). Pygofer diamond-
shaped with base truncated in ventral view. Up-
per lobes of pygofer angulated twice on lower side
in lateral view. Upper lobes of pygofer nearly
touching each other at apices in ventral view. Dor-
sal beak long and slender. A pair of claspers
present, which are long and pointed at tip. Apex of
aedeagus with a sclerotized crest.
Description of Female (Fig. 2). Fore wing with
an infuscation on radial, radiomedial, medial, and
mediocubital crossveins. Operculum narrowly
margined with black on about basal 23 of lateral
margin. Lateral margin of operculum a little sin-
uate at base. Abdominal segment 9 mostly fus-
cous with some paler parts dorsally and laterally.
Ovipositor sheath fuscous, slightly beyond anal
styles. Dorsal beak slightly longer than protrud-
ing part of ovipositor sheath.
Distribution. Sulawesi, Indonesia.

ACKNOWLEDGMENTS
I am indebted to Dr. B.-K. Byun (Korea National Ar-
boretum, Pocheon, Korea) for the loan of specimens. I
am grateful to Dr. J. P. Duffels (Zoological Museum, Am-
sterdam, The Netherlands) and anonymous reviewers
for suggestions that improved the manuscript. This
work benefited from support from the University of
Connecticut and the National Science Foundation un-
der Grant Numbers DEB 05-29679 and DEB 07-20664.
Any opinions, findings, and conclusions or recommenda-
tions expressed in this material are those of the authors
and do not necessarily reflect the views of NSF.

REFERENCES CITED
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trolabe ex6cut6 par ordre du Roi, pendant les ann6es
1826-1827-1828-1829, sous le commandement de M.
J. Dumont d'Urville. Faune entomologique de
l'Ocean Pacifique, avec l'illustration des insects
nouveaux recueillis pendant le voyage. Deuxi6me







90 Florida Ento



parties, Col6opteres et autres ordres. J. Tastu, Paris,
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BREDDIN, G. 1900. Hemiptera gesammelt von Professor
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der senckenbergischen naturforschenden Gesell-
schaft 25: 139-202, pl. 9.
BREDDIN, G. 1901. Die Hemipteren von Celebes, Ein Bei-
trag zur Faunistik der Insel. Abhandlungen der Natur-
forschenden Gesellschaft zu Halle 24: 1-213, pl. 1.
DISTANT, W. L. 1888a. Descriptions of new species of
eastern Cicadidae in the collection of the Museo Civ-
ico of Genoa. Annali de Museo Civico Storia Natu-
rale Giacomo Doria (2), 6: 519-524.
DISTANT, W. L. 1888b. Descriptions of new species of
Oriental Homoptera belonging to the family Cica-
didae. Annals and Magazine of Natural History (6),
1: 291-298.
DUFFELS, J. P. 1970. The synonymy of Diceropyga oper-
cularis (Walker) and D. insularis (Walker) with a de-
scription of D. breddini n. sp. (Homoptera, Cica-
didae). Ent. Ber. Amst. 30: 9-16.


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ologist 92(1) March 2009



DUFFELS, J. P. 1977. A revision of the genus Diceropyga
Stal, 1870 (Homoptera, Cicadidae). Monografieen
van de Nederlandse Entomologische Vereniging 8: 1-
227.
DUFFELS, J. P. 1990. 1,'.-. ... ..1 janstocki n. sp., a new
cicada endemic to Sulawesi (Homoptera, Cicadidae).
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Auchenorrhyncha: Cicadomorpha: Cicadidae). Re-
ichenbachia 33(9): 81-86.
LEE, Y. J. 2008. A checklist of Cicadidae (Insecta: Hemi-
ptera) from Vietnam, with some taxonomic remarks.
Zootaxa 1787: 1-27.
MOULDS, M. S. 2005. An appraisal of the higher classifi-
cation of cicadas (Hemiptera: Cicadoidea) with spe-
cial reference to the Australian fauna. Records of the
Australian Museum 57: 375-446.
WALKER, F. 1858. Homoptera. Insecta saundersiana: or,
characters of undescribed insects in the collection of
William Wilson Saunders, Esq. pp. 1-117.







Trout & Brown: Mosquito Suppression with Lambda-cyhalothrin


IMPACT OF RESIDUAL INSECTICIDE APPLIED TO UPPER STORY
VEGETATION ON RESTING ADULT MOSQUITOES (DIPTERA: CULICIDAE)

R. T. TROUT AND G. C. BROWN
Department of Entomology, University of Kentucky, Lexington, KY 40546-1120

ABSTRACT

Increased threat of mosquito-vectored diseases necessitates the development for new man-
agement tactics and programs. We tested a pyrethroid barrier treatment by using a power
sprayer to target upper tree canopies against orniphilic and other resting mosquitoes. Mos-
quito populations were monitored weekly with CO,-baited Centers for Disease Control
(CDC) miniature light traps (without a light) (1) at ground level (1.5 m), and (2) in the tree
canopy (4.9 m), and (3) with CDC gravid traps to collect mosquitoes at ground level and
within the vegetation. Traps were operated weekly for 10 weeks; 2 weeks pre- and 8 weeks
post-treatment. Culex spp. were collected predominantly in tree canopy CO,-baited traps
(81%) compared with CO,-baited traps at ground level (11%) and gravid traps (7%). Over
96% of the mosquitoes collected were Culex spp. Pretreatment canopy catches averaged
489.7 and 618.6 adults per trap-night prior to insecticide treatment in the control and treat-
ment plots, respectively. Tree canopy treatments significantly reduced populations ofAedes
spp. and Culex spp. At 4 weeks post-treatment, mosquito numbers collected in CO,-baited
traps were reduced by 86% at ground level and 76% in tree canopies. No reduction in mos-
quito numbers was noted in gravid traps. These data demonstrated that pyrethroid barrier
sprays applied to upper canopy vegetation might be effective in reducing adult mosquito
populations.

Key Words: Culex, adulticide, management, tree canopy, lambda-cyhalothrin, traps, insecti-
cides

RESUME

El aumento en la amenaza de enfermedades transmitidas por vectores de mosquitos
exige el desarrollo de nuevos programs y tacticas. Nosotros probamos un tratamiento
que consisti6 de una barrera de piretroide usando un rociador propulsado para alcanzar
la copa de los arboles contra mosquitos ornifilicos y otros mosquitos residents. Se rea-
lizo un monitoreo semanal de la poblaci6n de los mosquitos usando trampas miniaturas
de luz (pero sin luz) cebadas con CO hechas por los Centros de Control de Enfermedades
(CDC)(1) al nivel de la tierra (1.5 m), y (2) en la copa del arbol (4.9 m) y (3) con trampas
gravidas hechas por el CDC para recolectar mosquitos a nivel de tierra y dentro la vege-
taci6n. Las trampas fueron operadas semanalmente por 10 semanas; 2 semanas pre-tra-
tamiento y 8 semanas pos-tratamiento. Las species del genero Culex fueron
recolectadas predominantemente en las trampas localizadas en la copa del arbol cebadas
con CO i en comparaci6n con las trampas cebadas con CO, al nivel de tierra (11%)
y las trampas gravidas (7%). Mas del 96% de los mosquitos recolectados fueron Culex
spp. El promedio de las captures de la copa pre-tratada fue 489.7 y 618.6 adults por
trampa por noche antes del tratamiento de insecticide en el control y parcelas tratadas,
respectivamente. Los tratamientos a la copa del arbol redujeron significativamente las
poblaciones deAedes spp. y Culex spp. A las 4 semanas de pos-tratamiento, el nmmero de
mosquitos recolectados en las trampas cebadas con CO fue reducido al 86% en el nivel
de la tierra y 76% en la copa de los arboles. No se noto una reducci6n en el nmmero de
mosquitos en las trampas gravidas. Estos datos demuestran que los rocios de barreras
de piretroides aplicados en la vegetaci6n de la copa superior pueden ser efectivos en re-
ducir la poblaci6n de mosquitos adults.


West Nile virus (WNV) is one of many mosquito- al. 2001). In the eastern United States, the Culex
vectored encephalitis viruses that concern citizens pipiens L. complex is responsible for the majority
throughout the United States. WNV, a Flaviuirus, of WNV isolations from field-collected mosquitoes
caused over 9,800 disease cases in the United (CDC 2000). In Kentucky (USA), Aedes (Stego-
States in 2003 (CDC 2004). The WNV reservoir myia) albopictus (Skuse) is the dominant anthro-
and most isolates were from birds, especially crows pophillic mosquito, while Cx. pipiens L. is the prev-
and other corvids showing that most isolations alent WNV vector (Billings & Mahl 2002).
were identified from bird-feeding Culex spp. Public awareness of WNV has generated a de-
(Hayes 1989; Hubalek & Halouzka 1999; Turell et mand for improved mosquito control. Most pro-







Florida Entomologist 92(1)


grams rely on proactive control methods such as
source reduction accomplished primarily through
education. In addition, some municipal services
include reactive control, i.e., larviciding or utiliz-
ing non-residual chemical control with ultra-low
volume (ULV) fog generators. However, these tac-
tics only provide temporary control. Common
non-residual ULV adulticides include an organo-
phosphate (malathion) or pyrethroids (pheno-
thrin, allethrin, and resmethrin); all of which pro-
vide quick knockdown without residual effects
(Dame & Fasulo 2002). Insecticides formulated to
provide residual effectiveness include bifenthrin,
lambda-cyhalothrin, and cyfluthrin when applied
to primary adult resting sites, causing mosquitoes
to absorb a lethal dose upon contact with treated
surfaces (Dame & Fasulo 2002). These residual
insecticides have demonstrated long-term efficacy
on a variety of surfaces (Ansari et al. 1986; Singh
et al. 1989; Yadav et al. 1996; Trout et al. 2007).
Trout et al. (2007) reported that lambda-cyhalo-
thrin and bifenthrin applied with a mist blower
suppressed peridomestic mosquito numbers in
residential backyards. The treatments reduced
backyard adult Aedes spp. and Ochlerotatus spp.
numbers for 8 weeks post-treatment. However,
this tactic did not significantly reduce Culex spp.
numbers.
Barrier treatments have been effective against
adults of numerous species, including Aedes tae-
niorhynchus (Wiedemann), Ae. sollicitans
(Walker) (Madden et al. 1947; Anderson et al.
1991), Ae. stimulans (Walker) (Helson & Sur-
geoner 1983), Ae. albopictus (Trout et al. 2007),
Anopheles quadrimaculatus Say (Ludvik 1950),
An. albimanus (Taylor et al. 1975), and An. dar-
lingi Root (Hudson 1984). This concept involves
the creation of an insecticidal barrier between the
host seeking or resting mosquitoes and the com-
munity (Perich et al. 1983). Here we report a
strategy using tree lines treated with a residual
formulation of lambda-cyhalothrin to provide a
barrier between mosquitoes, especially Culex spe-
cies, and human populations.

MATERIALS AND METHODS

Two tree lines (~2.5 km apart) were selected
for treatment with lambda-cyhalothrin applied
with a power sprayer in the summer of 2005 at
the University of Kentucky's Mosquito Research
Center on Spindletop Farm of Lexington KY
(08428'W, 038004'N). A randomized complete
block design controlled for the differences be-
tween tree lines. The first tree line was divided
into 2 blocks, while the second tree line was di-
vided into 4 blocks. Each block was at least 30.5
linear m away from the next block. Blocks were
divided into 2 plots (1 treatment and 1 control)
separated by a 30.5 linear m buffer. Each plot
within the block was 30.5 linear m long and


shared similar canopy characteristics (tree
height, vegetation type, age, etc.). Therefore, each
block of 2 plots and buffer zone totaled 91.5 linear
m.
Within the blocks, each plot was randomly as-
signed either a water control or a pyrethroid
treatment (Demand@ CS, Al lambda-cyhalothrin,
Syngenta Crop Protection, Greensboro, NC.).
Both treatments were applied by a certified com-
mercial pesticide applicator (All-Right Pest Con-
trol, Inc., Lexington, KY) on 18-VII-2005.
Lambda-cyhalothrin concentrate, 6.25 mL formu-
lation/L, was diluted with water as directed on
the label. Treatments were applied when the
weather was forecasted to be clear, dry, and with
little to no wind. A power sprayer equipped with a
JD-9 spray gun (Green Garde, H.D. Hudson
Manufacturing Company, Japan; Model E1526-
17-18 LT Hannay Reels, Inc., Westerlo, NY
12193-0159; Honda 5HP) was used to apply the
treatments to all vegetative surfaces between ap-
proximately 0.3 m and 20 m in height and were
sprayed to near runoff. The operator inserted the
sprayer tip into thick low-lying foliage briefly to
ensure treatment of the interior canopy. Treat-
ments were applied to upper tree canopies by ad-
justing the pressure of the spray gun to deliver a
stream. Spray volume, time spent at each site,
and prevailing weather conditions were recorded
for each application. Finished spray volumes
ranged from 11.36 to 83.28 L (mean SEM: 42.78
5.72 L), depending on the amount of foliage and
tree canopy height.

Mosquito Monitoring

In each plot, 2 weeks before and 8 weeks after
treatment, mosquito populations were monitored,
totaling 10 sampling weeks (7-VII-7-IX-2005).
Mosquito populations were monitored weekly
with Centers for Disease Control (CDC) minia-
ture light traps (Model 512, John W. Hock,
Gainesville, FL) at 2 heights: (1) at ground level
(1.5 m) and, (2) in tree canopy (4.9 m) and CDC
gravid traps (Model 1712, John W. Hock, Gaines-
ville, FL) to collect mosquitoes at ground level and
within the vegetation. All traps were operated be-
tween 1500 and 1000 h. Trap contents were fro-
zen, counted, and identified in the laboratory.
The lights were removed from both CO2-baited
traps to reduce non-target collections and then
baited with ~2.3 kg of pelleted dry ice. Blue "Con-
tourTM 0.5" gallon- (1.89-L) coolers (Igloo Products
Corp., Houston, TX) held the dry ice, which al-
lowed CO2 to escape via 4 holes: 1 drilled in each
side, 1 drilled in the bottom, and from the opened
cooler spout at the top. A 0.6- m length of clear Ty-
gon tubing (1.27 cm outer diameter x 0.95 cm in-
ner diameter Vinyl Tubing, Model 089) connected
the bottom of the cooler to the top of the trap,
thereby directing CO, directly into the top of the


March 2009







Trout & Brown: Mosquito Suppression with Lambda-cyhalothrin


trap. A 1.5-m standard garden hook (Black Shep-
ard Hook, Model 843115A; Gilbert and Bennett
Manufacturing Company, China) suspended each
CDC ground level trap and cooler. Tree canopy
traps were held in place with a rope-pulley-hook
hung from a tree branch ranging from 3.89 to 6.22
m (mean SEM: 4.89 0.27 m) in height. The
pulley system remained in the tree throughout
the study. To get the rope-pulley-hook into the
tree canopy a 9.14-m (30-ft) pole was used. The
rope-pulley-hook allowed traps to be lifted into
and lowered from the tree canopy from the
ground. The standard garden hook for ground
level traps (1.5 m) and the hook-pulley on the
tree's branch (4.89 m) standardized collection pro-
cedures. Both traps were placed within proximity
(~5 m) of one another within each plot.
Ovipositing mosquitoes were collected from
gravid traps that were placed at ground level be-
neath tree canopies and within the vegetation.
The traps were baited with 4 L of an infusion con-
sisting of a 2-week-old mixture of 0.5 L of fescue
grass clippings, about 100 g of rabbit food (Big
Red Rabbit Food, Pro-pet@ L.L.C., St. Mary's,
OH), and 19 L of distilled water. Within each plot,
gravid traps were spaced ~15 m away from the
CO2-baited traps.
Meteorological data were recorded during each
visit. Traps were setup in the evening and re-
trieved the following morning. A handheld meteo-
rological instrument (Kestrel@ 3000, Nielson-
Kellerman, Boothwyn, PA) was used to measure
temperature (C), percent relative humidity (%
RH), heat index (C), wind speed (m/min), and
wind direction. Meteorological data, from the
evening and morning observations, were aver-
aged.

Statistical Analyses

All statistical analyses used the Statistical
Analysis System (SAS Institute 2001). To deter-
mine overall pyrethroid treatment effects, col-
lected mosquitoes were log(x + 1) transformed.
The transformed data were analyzed with Proc
Mixed by ANOVA repeated measures and means
were separated by Tukey's Least Square Means
test. Trap percentage reductions were calculated
from Mulla's formula:


Percent Reduction = 100 + x 2 100
VTi C,

where C, is the number of mosquitoes at the con-
trol site pretreatment, C2 is the number of mos-
quitoes at the control site post-treatment, T1 is the
number of mosquitoes at the treatment site pre-
treatment, and T2 is the number of mosquitoes at
the treatment site post-treatment (Mulla et al.
1971).


RESULTS

Weather Analysis

The mean ( SEM) temperature during the en-
tire study was 32.04 ( 0.3) C (range 25.5 to
39.2C) during trap setup and 30.36 (0.4) C
(range 22.8 to 42.0C) during trap retrieval. The
mean ( SEM) relative percent humidity was
49.39 ( 1.5) %R.H. (range 24.0 to 88.0 %R.H.)
during trap setup and 57.33 ( 1.7) %R.H. (range
28 to 96 %R.H.) during trap retrieval. The overall
mean ( SEM) wind speed among the 3 treat-
ments was 0.5 ( 0.1) m/min. The overall mean (
SEM) heat index was 35.06 ( 0.4) oC (range 27.4
to 47.50C) during trap setup and 33.00 ( 0.5) C
(range 22.2 to 51.30C) during trap retrieval. Pre-
cipitation totaled 16.64 cm over the course of the
experiment. Of the 16.64 cm of rain, 49% occurred
during the 2-week pretreatment period. Over the
entire study, the amount of rain was 0.08 cm be-
low normal (www.agwx.ca.uky.edu).
During treatment applications, environmental
conditions in each block were not significantly dif-
ferent from one another. The environmental con-
ditions during treatment had a mean ( SEM)
wind speed of 0.3 ( 0.1) m/min (range 0 to 0.7 m/
min), a mean temperature of 31.4 ( 0.5) C
(range 29.2 to 34.30C), and a mean heat index of
38.8 ( 0.9) oC (range 34.3 to 45.3 oC). The mean
R.H. for pyrethroid treated sites was 67.8 ( 1.5)
% R.H., and 79.4 ( 2.5) %R.H. in control sites.
Climate data did not differ significantly over the
study.

Mosquito Composition

During the 10-week sampling period, we col-
lected 10,925 mosquitoes, consisting primarily of
Culex spp. (96.4%, Table 1). The majority of mos-
quitoes were collected in C02-baited traps within
the tree canopies (81%). C02-baited traps at
ground level and gravid traps collected 12% and
7%, respectively. The predominant collected mos-
quito was Cx. pipiens/restuans (93.8%) followed
in descending order by Cx. restuans (Theobald)
(2.4%), and Cx. erracticus (Dyar and Knab)
(1.7%). Other genera included Aedes spp. (0.4%),
Anopheles spp. (0.2%), Ochlerotatus spp. (<0.1%),
and an assortment of other species (1.6%). Due to
the large number of mosquitoes collected in the
traps in 1 night, some of the specific species could
not be identified. Specifically, a large percent of
Culex mosquitoes were lumped into an arbitrary
Culex pipiens restuans cohort for further analy-
ses.

Trap Analyses

Back transformed mosquito collection means (
SEM) are presented in Table 2. Mean post-treat-







Florida Entomologist 92(1)


TABLE 1. SPECIES COMPOSITION OF QUESTING AND GRAVID MOSQUITOES COLLECTED AT THE MOSQUITO RESEARCH FA-
CILITY IN SPINDLETOP FARM, LEXINGTON, KENTUCKY ALONG TREE LINES, (7-VII -7-IX-2005).


CO, Trap
in Tree Canopy


Species


Aedes albopictus
Ae. Vexans
Anopheles punctipennis
An. quadrimaculatus
An. Walkeri
Culex erraticus
Cx. pipiens /restuans'
Cx. restuans
Culex spp.'
Ochlerotatus japonicus
Oc. triseriatus
Oc. triuittatus
Unknown/Unidentifiable
Total


1
3
0
65
8598
90
134
0
0
0
0
8892


CO, Trap
at Ground Level


Gravid Trap

9
9
1
0
0
16
682
37
15


1
1
11
1263


Total

19
19
5
9
2
190
10251
265
150
1
1
1
12
10925


Indicates collected specimens were damaged and could not be properly identified to species.


ment results differed with each trapping method.
CO2-baited traps at ground level post-treatment
collected a cumulative mean ( SEM) of 2.1 ( 0.8)
mosquitoes per trapping night at lambda-cyhalo-
thrin treated plots compared with 8.1 ( 2.5)/night
at control plots. Treatments reduced mosquito
numbers in CO2-baited traps at ground level by
86.5% over 4 weeks post-treatment and 72.1%
over 6 weeks post-treatment compared to the con-
trol treated tree lines. CO,-baited traps at ground
level demonstrated a significant treatment effect
for 8 weeks post treatment (F = 37.01; df= 1, 79;P
< 0.0001), a significant week effect (F = 6.52; df =
7, 79; P < 0.0001), and a significant treatment
week interaction effect (F = 2.55; df = 7, 79; P =
0.0204). In addition, a significant treatment effect
(F = 37.14; df =1, 79; P < 0.0001), week effect (F =
7.35; df = 7, 79; P < 0.0001), and treatment week
interaction effect (F = 2.18; df = 7, 79; P = 0.0451)
was observed for Culex mosquitoes (Fig. 1A). Dif-
ferences of least square means showed those post-
treatment weeks immediately following treat-
ment were significantly different from those ap-
proaching the end of the study for both total mos-
quito counts and Culex mosquitoes collected in
CO0-baited traps at ground level.
Tree canopy CO,-baited traps collected a cu-
mulative mean ( SEM) of 10.1 ( 3.5) questing
mosquitoes per trap-night, while untreated con-
trol plot traps collected a post-treatment cumula-
tive mean of 51.3 ( 23.4) questing mosquitoes per
trap-night. The treatment significantly reduced
mosquito collections in these traps by 76.6% over
4-week post-treatment and 71.9% over 6-week
post-treatment compared to those in the un-
treated control traps (F = 6.29; df = 1, 79; P =
0.0142). Significant week effects (F = 6.12; df= 7,


79; P < 0.0001) were observed in C0,-baited traps
within the tree canopy Analysis of only Culex
mosquitoes within the CO2-baited traps in the
tree canopies showed a significant treatment (F =
6.40; df= 1, 79; P = 0.0134) and week (F = 6.21; df
=7, 79; P < 0.0001) effect (Fig. 1B). Similar to the
ground level CO,-baited traps, the tree canopy
CO,-baited traps had significant week effects be-
tween immediate post-treatment week (weeks 1,
2, and 3) and weeks near the end of the study
(weeks 6, 7, and 8).
Contrary to the questing traps, gravid trap col-
lections were not significantly reduced in treat-
ment plots when compared to the untreated con-
trol. A mean ( SEM) of 23.1 ( 3.4) gravid mos-
quitoes per trap-night were collected from treated
plots, while control treated plots collected a post-
treatment mean of 25.8 ( 3.7) gravid mosquitoes
per trap-night. Gravid trap collection means were
not significantly different at treated plots com-
pared to untreated control sites (P > 0.05). Addi-
tionally, Culex spp. collections in gravid traps
were not significantly affected by the treatments
(P > 0.05, Fig. 1C). However, significant week ef-
fects occurred for the total collections (F = 2.18; df
= 7, 80; P = 0.0446) and Culex spp. analyses (F =
6.51; df= 7, 85;P < 0.0001).
Of the 41 Aedes/Ochlerotatus mosquitoes col-
lected, the majority was either Ae. albopictus or
Ae. vexans (Meigen). Most of the Aedes spp. were
collected in CO0-baited ground traps (54%) and
gravid traps (44%). Only one Aedes mosquito was
collected from a CO,-baited trap within the tree
canopy The treatment reducedAedes numbers by
55.3%, and 57.0% after 4 and 6 weeks post-treat-
ment, respectively. Due to the small collections,
statistical tests were not conducted.


March 2009








Trout & Brown: Mosquito Suppression with Lambda-cyhalothrin


TABLE 2. MEAN ( SEM) MOSQUITOES COLLECTED WEEKLY PER TRAP-NIGHT AT SPINDLETOP FARM IN LEXINGTON, KY1.

Cumulative Weekly Mosquitoes Collections

Control Pyrethroid Cumulative
Sampling Method Week Treatment Treatment Percent Reduction2


CO2-baited CDC trap at ground level


Post-treatment Mean
CO2-baited CDC trap in the tree canopy


Post-treatment Mean
Gravid Trap


Post-treatment Mean
Total: All Traps


Post-treatment Mean


-2 9.5 3.2
-1 47.7+ 11.0
1 26.3 8.7
2 6.2 1.6
3 5.2 1.5
4 12.7 3.1
5 6.7 2.2
6 3.2 1.6
7 3.2 0.9

8 1.3 0.6

8.1 2.5
-2 35.0 31.0
-1 489.7 201.6
1 245.0 103.4
2 41.0 12.5
3 19.2 6.9
4 26.0 10.1
5 67.3 49.6
6 3.0 1.3
7 7.2 2.2
8 1.8 1.2

51.3+ 23.4
-2 18.8 4.6
-1 26.8 7.1
1 30.0 4.7
2 24.8 5.1
3 25.0 3.5
4 20.5 2.1
5 31.7 4.7
6 28.2 3.8
7 22.5 2.8
8 23.5 3.1

25.8 3.7
-2 27.0 9.4
-1 550.2+ 215.0
1 286.3 108.1
2 56.0 15.4
3 32.3 6.8
4 41.2 11.3
5 53.0 25.7
6 10.7 3.1
7 11.8 2.8
8 4.7 2.0
62.0+ 21.9


18.5 6.7
54.0 19.5
4.7 1.9
1.3 0.3
0.8 0.4
1.7 0.7
3.7 1.7
2.8 0.7
0.5 0.5

1.2 0.4

2.08 0.8
46.5 12.5
618.6 196.8
29.0 10.8
11.8+ 3.9
5.7 1.8
12.7 3.9
15.0 5.1
2.1 0.7
2.6 0.9
1.8 0.9

10.1 3.5
17.7 3.6
18.5 2.2
36.0 9.7
21.5 2.2
20.2 3.1
18.0 1.6
23.2 2.9
22.4 2.3
21.8 2.9
21.7 2.3

23.1 3.4
39.7 15.4
575.0 198.7
55.7 4.5
17.7 2.0
10.7 2.0
15.3 4.7
18.8 3.8
6.7 1.6
4.5 1.5
3.7 1.0
16.6 2.6


86.0%
84.5%
85.4%
86.5%
80.5%
72.1%
74.3%

68.9%

79.8%



90.7%
84.0%
81.5%
76.6%
77.7%
71.9%
71.9%
65.5%

77.5%


81.7%
76.1%
73.7%
71.5%
70.6%
65.7%
65.5%
60.6%
70.7%


'Treatments were applied between weeks -1 and 1 (18-VII-2005).
Cumulative percent reduction was calculated with Mulla's formula. Percent reductions were significant at (a = 0.05). Values
that were not significant, or weeks when reductions were not applicable, are denoted with a dash (-).


Culex spp. were collected primarily in CO2- post-treatment, the treatment reduced Culex
baited tree canopy traps (82%). After 4 weeks numbers by 76.4% and 72.0% after 6 weeks, re-







Florida Entomologist 92(1)


S30/ I

C 1000 t .
S800 B
o 600
400
3 200
7 125
150
1
6 0 L -b -- .'T
Z 30
ST c
u 25 -
E 20
15 T
10 -
5 T '
1000 1 All I
800 D
600
400
400 i.
125 /
100
75 L
0
-2 -1 1 2 3 4 5 6 7 8
Treatment Week
Fig. 1. Back-transformed mean ( SEM) of Culex
spp. mosquitoes collected once a week for 10 weeks with
CO2-baited traps at ground level (A), CO,-baited traps
in the tree canopy (B), gravid traps (C), and all traps
(D). All treatments applied between week -1 pretreat-
ment and 1 post-treatment (18-VII-2005).


spectively. Post-treatment means ( SEM) of
mosquitoes in treated plots were 16.3 ( 2.6) mos-
quitoes per trap-night compared to 61.5 ( 22.0)
mosquitoes per trap-night in control treated
plots. Significant treatment (F = 20.71; df= 1, 87;
P < 0.0001) and week (F = 19.30; df = 7, 87; P <
0.0001) effects occurred (Fig. 1D).

Overall Monitoring Analysis

Analyses of all the mosquitoes collected
showed significant treatment (F = 16.22; df= 1,
87; P = 0.0001) and week (F = 5.39; df = 7, 87; P
< 0.0001) effects. The overall post-treatment
mean of mosquitoes collected per trap-night
within treated plots (16.6 2.6) was signifi-
cantly fewer than mosquitoes collected per
trap-night within control treated plots (62.0 +
21.9). The treatment reduced total mosquito
populations by a mean of 71.5% and 65.7% over
4 and 6 weeks, respectively.


DISCUSSION

Lambda-cyhalothrin residual application re-
duced questing mosquito numbers. The power
sprayer treated higher vegetation thereby sup-
pressing host seeking or resting mosquitoes.
Placing monitoring traps in tree canopies and
at ground level allowed us to collect data rela-
tive to treatment impacts. This treatment
method significantly reduced Culex and total
combined mosquitoes in pyrethroid treated
plots when compared to the untreated control
plots. In addition, ground and tree canopy CO2-
baited traps collected significantly fewer adult
mosquitoes at treated plots compared to un-
treated control sites. Mosquito numbers were
reduced in control plots over time, most likely
due to the 30.5 m distance separating the plots
within each block and from the untreated con-
trol plots. This short distance may have affected
the mosquito populations at control plots be-
cause the pyrethroid may have acted as a repel-
lent. Additionally, the treatment may have re-
duced the general mosquito population along
the entire tree line.
Species composition analyses showed that pre-
treatment week effects were most likely due to
the rainfall that occurred before the study was
initiated (0.36 cm), and the scattered incidences
of rain throughout. The pretreatment rainfall
provided Culex species with established oviposi-
tion sites.
Culex species comprised a majority of the Culi-
cid population along the tree lines. In 2004, Trout
et al. (2007) reported that a majority of Aedes or
Ochlerotatus mosquitoes were collected in CO2-
baited light traps (without the light) at ground
level in Lexington city residencies. Our previous
study found questing Aedes and Ochlerotatus
mosquitoes were dominant in CO,-baited traps
placed at ground level, while questing Culex mos-
quitoes were collected in CO,-baited traps placed
in the tree canopy; a potential difference in site
preference. Tree canopy CO,-baited traps col-
lected a significantly larger number of Culex spe-
cies. The plots utilized in the study were com-
prised of numerous tree lines with scattered and
clumped vegetation that was home to roosting
birds. Additionally, the tree lines were adjacent to
areas with watering holes for farm animals and
large holes in the field produced by agriculture
equipment. The presence of birds and standing
water as oviposition sites may have increased the
Culex mosquito population. In 2004, Trout et al.
(2007) used residential neighborhoods that con-
tained various vegetation types based on home-
owner preference. Bird populations and potential
ovipositing sites at city residencies may have
been largely scattered, resulting in fewer Culex
collections and populations. Additionally, CO2-
baited traps were not placed in tree canopies at


March 2009







Trout & Brown: Mosquito Suppression with Lambda-cyhalothrin


homeowner residences; consequently, Culex mos-
quitoes may not have been adequately sampled.
Statistical analyses of host seeking or resting
Culex mosquitoes corroborated with previously
published studies that showed Culex spp. prefer to
inhabit upper tree canopies closer to their avian
blood meals than at ground level (Burgess &
Haufe 1960; Main et al. 1966; Novak et al. 1981;
Lundstrom et al. 1996; Bellini et al. 1997; Crisp &
Kneeper 2003; Anderson et al. 2004; Farajollahi et
al. 2005). At control treated sites, significantly
more Culex spp. were collected in the tree canopies
compared to ground level. However, at pyrethroid
treated sites, no differences were observed in CO,-
baited trap at collection heights suitable for Culex
species. This lack of significant preference at the
treatment sites may be largely due to the treat-
ment's ability to control or repel Culex species. Ad-
justing the spray nozzle from a spray to a stream
allowed treatment of upper tree canopies. This
treatment method reduced Culex mosquito densi-
ties in tree canopies comparable to those at
ground level, suggesting treatment uniformity.
Mosquitoes collected in gravid traps were not
significantly reduced. This observation was simi-
lar to previous studies where insecticide treat-
ments did not reduce gravid mosquito collections
(Eliason et al. 1990; Moore et al. 1990; Reiter et
al. 1990; Trout et al. 2004). Previous research in-
dicates gravid Culex mosquitoes may not be af-
fected by insecticide treatments in urban habitats
(Moore et al. 1990). This finding emphasizes the
need for incorporating larviciding with adulticide
treatments.
This study applied a residual pyrethroid
higher into tree canopies significantly reducing
Culex populations at treated plots when com-
pared to untreated control plots for 8 weeks post-
treatment. This may indicate that Culex mosqui-
toes prefer questing or resting in tree canopies
closer to their preferred avian blood meals. In ad-
dition, mosquitoes may have encountered pyre-
throid repellency because treatments to the tree
lines occurred along 2 axes, horizontal and verti-
cal. This treatment method allowed for repellency
by providing an untreated outlet for mosquitoes
to escape. Past studies have demonstrated a re-
pellent effect of DDT (dichloro-diphenyl-trichloro-
ethane), deltamethrin, and lambda-cyhalothrin
(Chareonviriyaphap et al. 2001). Future studies
should investigate the repellency of these chemi-
cals to ensure mosquito management and not dis-
placement.
Data obtained in the present study indicate re-
sidual spraying is a viable control tactic for control
of Culex species. An integrated mosquito manage-
ment program that includes this tactic along with
education, surveillance, source reduction, exclu-
sion (screening), larviciding, and adulticiding
(with different modes of action) may further de-
crease resistance rates and mosquito numbers.


ACKNOWLEDGMENTS

We express thanks to the National Pest Manage-
ment Association for support of the project as well as
funding the Mosquito Management Facility at Spindle-
top Farm in Lexington, Kentucky. We thank T. Myers
and C. Asbury (All-Rite Pest Control) for helping with
the treatment applications. We thank M. Potter, L.
Townsend, J. Hubbard, A. Dunn, E. Rice, K. Muller, M.
Todd, E. Yost, and Zin for assistance. In addition, we
thank S. McClintock for statistical advice. We appreci-
ate F. Knapp, C. D. Steelman, and R. Wiedenmann for
professional advice and manuscript review.

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