• TABLE OF CONTENTS
HIDE
 Potential biodiversity loss in...
 Mating success of male Mediterranean...
 Synonomy of five Scirtothrips species...
 Biological control of Pieris rapae...
 Neomusotima fuscolinealis (Lepidoptera:...
 A new Parelbella from Mexico (Hesperiidae:...
 Citrus flushing patterns, Diaphorina...
 A new lestodiplosine (Diptera:...
 Two new species and distribution...
 Bionomics of Oncometopia tucumana...
 Fall armyworm strains (Lepidoptera:...
 Solenopsis enigmatica, a new species...
 Efficacy of entomopathogenic nematodes...
 Climatological potential for Scirtothrips...
 Laboratory and field evaluations...
 Naturalization of the oil collecting...
 A new genus Pectinimura (Lepidoptera,...
 Adding ginger root oil or ginger...
 Nectar sources for Eumaeus atala...
 Gratiana boliviana (Coleoptera:...
 Aggregation of Calopteron discrepans...
 Autotomy in a stick insect (Insecta:...
 Euoniticellus intermedius (Coleoptera:...
 Solenopsis invicta: evidence for...
 Ovigeny in selected generalist...
 Trophic interactions involving...
 Planning for tomorrow: the future...
 Book reviews
 Back Matter














Group Title: Florida Entomologist
Title: The Florida entomologist
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Permanent Link: http://ufdc.ufl.edu/UF00098813/00355
 Material Information
Title: The Florida entomologist
Uniform Title: Florida entomologist (Online)
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Language: English
Creator: Florida Entomological Society
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Publication Date: March 2008
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Subject: Entomology -- Periodicals   ( lcsh )
Insects -- Periodicals -- Florida   ( lcsh )
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periodical   ( marcgt )
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Additional Physical Form: Also issued in print.
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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.
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 Related Items
Preceded by: Florida buggist (Online)

Table of Contents
    Potential biodiversity loss in Florida bromeliad phytotelmata due to metamasius callizona (Coleoptera: Dryophthoridae), and invasive species
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
    Mating success of male Mediterranean fruit flies following exposure to two sources of (alpha)-copaene, manuka oil and mango
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
    Synonomy of five Scirtothrips species (Thysanoptera: Thripidae) described from avocados (Persea americana) in Mexico
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
    Biological control of Pieris rapae in New England: host suppression and displacement of Cotesia glomerata by Cotesia rubecula (Hymenoptera: Braconidae)
        Page 22
        Page 23
        Page 24
        Page 25
    Neomusotima fuscolinealis (Lepidoptera: Pryalidae) is an unsuitable biological control agent of Lygodium japonicum
        Page 26
        Page 27
        Page 28
        Page 29
    A new Parelbella from Mexico (Hesperiidae: Pyrginae: Pyrrhopygini)
        Page 30
        Page 31
        Page 32
        Page 33
        Page 34
        Page 35
    Citrus flushing patterns, Diaphorina citri (Hemiptera: Psyll1dae) populations and parasitism by Tamarixia radiata (Hymenoptera: Euloph1dae) in Puerto Rico
        Page 36
        Page 37
        Page 38
        Page 39
        Page 40
        Page 41
        Page 42
    A new lestodiplosine (Diptera: Cecidomyiidae) preying on the avocado lace bug, Pseudacysta perseae (Heteroptera: Tingidae) in southern Florida
        Page 43
        Page 44
        Page 45
        Page 46
        Page 47
        Page 48
    Two new species and distribution records of the genus Acroleucus in Mexico (Hemiptera: Heteroptera: Lygaeidae: Lygaeinae)
        Page 49
        Page 50
        Page 51
        Page 52
        Page 53
        Page 54
    Bionomics of Oncometopia tucumana (Hemiptera: Cicadellidae), a sharpshooter from Argentina, with notes on its distribution, host plants, and egg parasitoids
        Page 55
        Page 56
        Page 57
        Page 58
        Page 59
        Page 60
        Page 61
        Page 62
    Fall armyworm strains (Lepidoptera: Noctuidae) in Argentina, their associate host plants and response to different mortality factors in laboratory
        Page 63
        Page 64
        Page 65
        Page 66
        Page 67
        Page 68
        Page 69
    Solenopsis enigmatica, a new species of inquiline ant from the island of Dominica, West Indies (Hymenoptera: Formicidae)
        Page 70
        Page 71
        Page 72
        Page 73
        Page 74
    Efficacy of entomopathogenic nematodes versus Diaprepes abbreviatus (Coleoptera: Curculionidae) larvae in a high clay-content Oxisol soil: greenhouse trials with potted Litchi chinensis
        Page 75
        Page 76
        Page 77
        Page 78
    Climatological potential for Scirtothrips dorsalis (Thysanoptera: Thripidae) establishment in the United States
        Page 79
        Page 80
        Page 81
        Page 82
        Page 83
        Page 84
        Page 85
        Page 86
    Laboratory and field evaluations of Silwet L-77 and Kinetic alone and in combination with imidacloprid and abamectin for the management of the Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae)
        Page 87
        Page 88
        Page 89
        Page 90
        Page 91
        Page 92
        Page 93
        Page 94
        Page 95
        Page 96
        Page 97
        Page 98
        Page 99
        Page 100
    Naturalization of the oil collecting bee Centris nitida (Hymenoptera, Apidae, Centrini), a potential pollinator of selected native, ornamental, and invasive plants in Florida
        Page 101
        Page 102
        Page 103
        Page 104
        Page 105
        Page 106
        Page 107
        Page 108
        Page 109
    A new genus Pectinimura (Lepidoptera, Gelechioidea, Lecithoceridae), with four new species From Thailand and the Philippines
        Page 110
        Page 111
        Page 112
        Page 113
        Page 114
        Page 115
    Adding ginger root oil or ginger powder to the larval diet has no effect on the mat1ng success of male Mediterranean fruit flies
        Page 116
        Page 117
    Nectar sources for Eumaeus atala (Lepidoptera: Lycaenidae: Theclinae)
        Page 118
        Page 119
        Page 120
    Gratiana boliviana (Coleoptera: Chrysomelidae) does not feed on Jamaican nightshade Solanum jamaicense (Solanaceae)
        Page 121
        Page 122
        Page 123
    Aggregation of Calopteron discrepans (Coleoptera: Lycidae) larvae prior to pupation
        Page 124
        Page 125
        Page 125a
        Page 125b
    Autotomy in a stick insect (Insecta: Phasmida): predation versus molting
        Page 126
        Page 127
    Euoniticellus intermedius (Coleoptera: Scarabaeidae: Scarabaeinae: Tribe Coprini): its presence and relative abundance in cattle pastures in northcentral Florida
        Page 128
        Page 129
        Page 130
    Solenopsis invicta: evidence for recent internal immigration across provinces in Argentina
        Page 131
        Page 132
    Ovigeny in selected generalist predators
        Page 133
        Page 134
        Page 135
    Trophic interactions involving Herpetogramma phaeopteralis (Lepidoptera: pyralidae) and Passiflora incarnata (Passifloraceae)
        Page 136
        Page 137
        Page 138
    Planning for tomorrow: the future of entomological investments
        Page 139
        Page 140
        Page 141
        Page 142
        Page 143
        Page 144
    Book reviews
        Page 145
        Page 146
        Page 147
        Page 148
    Back Matter
        Page 149
Full Text



Frank & Fish: Aquatic Invertebrates in Florida Bromeliads


POTENTIAL BIODIVERSITY LOSS IN FLORIDA BROMELIAD
PHYTOTELMATA DUE TO METAMASIUS CALLIZONA
(COLEOPTERA: DRYOPHTHORIDAE), AN INVASIVE SPECIES

J. H. FRANK1 AND D. FISH2
'Entomology & Nematology Department, University of Florida, Gainesville, FL 32611-0630

2Department of Epidemiology and Public Health, Yale School of Medicine,
60 College St., P.O. Box 208034, New Haven, CT 06520

ABSTRACT

An annotated list of the aquatic invertebrates inhabiting water impounded in the leaf axils of
Florida's native epiphytic bromeliads is provided. Of the 22 species reported, 9 are yet unde-
scribed. Of the 13 described species, 10 are believed to be native. Five of the native species and
perhaps all of the undescribed species are precinctive ("endemic"). These invertebrate animals
and their bromeliad host plants are at risk of extinction due to destruction of the host plants
by Metamasius callizona (Chevrolat) (Coleoptera: Dryophthoridae), an invasive weevil.

Key Words: biodiversity, macro-invertebrates, endangered species, phytotelmata, precinc-
tive species, endemic species, invasive species

RESUME
Se provee una lista anotada de los invertebrados acuaticos que viven en agua acumulada en
las axilas de las hojas de bromeliaceas (Bromeliaceae) epifiticas nativas de Florida. De las
22 species reportadas, nueve no han sido descritas. De las 13 species descritas, 10 son apa-
rentemente nativas. Cinco de las species nativas y posiblemente todas las species no des-
critas son precinctivas ("end6micas"). Estos invertebrados y sus hospederos estan bajo riesgo
de extinci6n por Metamasius callizona (Chevrolat) (Coleoptera: Dryophthoridae), un gorgojo
invasive.


Translation provided by the authors.


In the early 1970s, D. Fish conducted an exten-
sive study of the aquatic invertebrate fauna of the
phytotelmata in the leaf axils of native bromeli-
ads from central Florida south to the Everglades,
but not the Florida Keys. Meanwhile, J. H. Frank
was conducting an intensive ecological and etho-
logical study of the mosquito genus Wyeomyia,
whose immature stages inhabit bromeliad leaf
axils in southern Florida. The Ph.D. dissertation
of Fish (Fish 1976) reported several species for
which specialist taxonomists were unable at that
time to provide species-level identifications. The
two investigators collaborated on chapters of a
book. Fish (1983) wrote about phytotelmata in
general. Frank (1983) wrote about bromeliad phy-
totelmata; included was a review of the knowl-
edge of the way of life of southern Florida's Wyeo-
myia mosquitoes; included also was a catalog of
aquatic organisms from bromeliad phytotelmata
worldwide with bibliography; this catalog in-
cluded records provided by Fish (1976).
In the late 1980s G. F. O'Meara (Florida Medi-
cal Entomology Laboratory) began studies on
mosquito larvae in imported, ornamental brome-
liads. Frank et al. (2004) reported on the total (not
just aquatic) macro-invertebrate fauna of a small


sample of native bromeliads in Sarasota County,
collected in 1997 by S. Sreenivasan, an intern at
the Marie Selby Botanical Gardens. Then, L. J.
Hribar (Florida Keys Mosquito Control District)
reported new finds of bromeliad-inhabiting
aquatic invertebrates from this limited area
(Wagner & Hribar 2005; Grogan & Hribar 2006;
Reid & Hribar 2006).
In 1989, an invasive weevil, Metamasius calli-
zona (Chevrolat), was detected in Broward
County, destroying native Florida bromeliads. Its
larvae mine the meristematic tissue and kill the
plants (Frank & Thomas 1994). By 2005, its pop-
ulations had spread to most southern Florida
counties, it threatened the survival of 12 of the 16
species (Table 1) of native Florida bromeliads, in-
cluding all those species that provide phytotel-
mata, and a biological control campaign had been
started to attempt to limit the destruction (Frank
& Cave 2005). Several native bromeliads had al-
ready been declared to be threatened or endan-
gered, and attrition by the weevil caused 2 more
to be placed on the list of endangered species
(Florida Administrative Code 1998). Natural bro-
meliad populations suffer losses due to natural
causes such as wind and breakage of tree







Florida Entomologist 91(1)


TABLE 1. FLORIDA NATIVE BROMELIADS, THEIR ABUNDANCE AND STATUS UNDER FLORIDA LAW, SUSCEPTIBILITY TO AT-
TACK BY M. CALLIZONA, AND WHETHER THEY PROVIDE PHYTOTELMATA.

Bromeliad species Florida status Attacked' Phytotelm2

Catopsis berteroniana Schult. (f.) Mez rare, endangered probably3 yes
Catopsis floribunda L.B. Sm. rare, endangered probably3 Yes
Catopsis nutans (Sw.) Griseb. very rare, endangered probably3 Yes
Guzmania monostachia (L.) Rusby ex Mez rare, endangered yes Yes
Tillandsia balbisiana Schult. and Schult. f. occasional, threatened yes No
Tillandsia fasciculata Sw. frequent, endangered yes Yes
Tillandsia flexuosa Sw. infrequent, threatened yes No
Tillandsia paucifolia Baker occasional yes No
Tillandsia pruinosa Sw. rare, endangered probably3 No
Tillandsia simulata Small frequent4 yes slight
Tillandsia utriculata L. frequent, endangered yes Yes
Tillandsia variabilis Schltdl.6 occasional, threatened yes Yes
Tillandsia bartramii Elliott frequent no No
Tillandsia recurvata (L.) L. common no No
Tillandsia setacea Sw. common no No
Tillandsia usneoides (L.) L. common no No

Attacked by larvae ofM. callizona.
'Forming phytotelmata.
Not yet seen to be attacked in nature in Florida perhaps only because it is rare. They or their close relatives have been seen to
be attacked in greenhouses.
'The only precinctive species.
"Listed as T valenzuelana Richard in Florida Administrative Code (1998).


branches, but M. callizona has increased those
losses to an unsustainable level. Death of Tilland-
sia utriculata and T fasciculata from natural pop-
ulations was monitored in the Myakka River
State Park (Sarasota County for 49 mo.), Loxa-
hatchee National Wildlife Reserve (Palm Beach
County, for 28 mo.), Highlands Hammock State
Park (Highlands County for 33 mo.), and St. Se-
bastian River Preserve State Park (Indian River
County for 17 mo.) ending in Jun 2005. The per-
centage deaths due to M. callizona ranged from
71% to 82%, far exceeding the deaths due to other
causes (Cooper 2006).
The fate of all specialist aquatic organisms in-
habiting phytotelmata in Florida's native brome-
liads may now depend upon the success of this bi-
ological control campaign. It is now urgent to cat-
alog the invertebrates that depend upon these
plants as habitat. This paper is an attempt to de-
scribe what may be lost if the weevil is not con-
trolled. Although vertebrates in Florida may use
bromeliads as food, concealment, hunting
grounds, or water sources (the free water in the
axils), no vertebrates depend upon bromeliads in
Florida as habitat for reproduction; it is the inver-
tebrate fauna that will be most affected.
We present an annotated list of the specialist
aquatic bromeliad-inhabiting organisms in Flor-
ida. Species that seem to be occasional inhabit-
ants are mentioned in passing. We attempt to dis-
tinguish the precinctive species (those that have
been detected only in Florida, often called "en-


demic", but see Frank & McCoy 1990) from spe-
cies with a wider distribution. For those species
with a wider distribution, we attempt to distin-
guish those that have been present for a long time
(probably pre-Columbian) from those that may
have arrived very recently as contaminants of im-
ported, ornamental bromeliads or other imported
materials. We start with the viewpoint that the
ancestors of Florida's native bromeliads arrived
as wind-dispersed seed (see e.g., Luther 1993).
The bromeliads established, dispersed, and began
to diverge. One result of their evolution in Florida
was the precinctive species Tillandsia simulata.
Other results included increasing genetic diver-
sity of Florida's native bromeliads and the evolu-
tion of natural hybrids which may be incipient
species. Once the bromeliads had colonized south-
ern Florida, they in turn were subject to coloniza-
tion by wind-blown invertebrates especially from
the Greater Antilles and Mexico's Yucatan penin-
sula. Then, the invertebrates began to evolve. It
must not be supposed that arrival of the bromeli-
ads or the invertebrates was a single event; in-
stead, there probably is continual natural arrival
(immigration) of propagules (Luther 1993), but it
has recently been complicated by inadvertent ef-
fects of international trade (human activities) in
allowing the arrival of additional invertebrate
species as contaminants of imported bromeliads.
When a species known only from Brazil has
been detected recently in Florida, we suspect that
it arrived as a contaminant of imported plants.


March 2008







Frank & Fish: Aquatic Invertebrates in Florida Bromeliads


When a species known from the Greater Antilles
has been known in Florida for decades, we sus-
pect that it arrived in pre-Columbian times.

SPECIALIST MACRO-INVERTEBRATES DETECTED
IN BROMELIAD PHYTOTELMATA IN FLORIDA

Turbellaria:
Family, genus and species unidentified, of Fish, 1976

Fish (1976) noted this turbellarian but was un-
able to obtain an identification. The record was re-
ported by Frank (1983) who had seen the organ-
ism occasionally in Tillandsia utriculata at Vero
Beach.

Annelida: Oligochaeta: Tubificidae, Naidinae
Dero Oken
Dero (Aulophorus) superterrenus Michaelsen, 1912

This aquatic annelid was reported as unidenti-
fied by Fish (1976), but was abundant in epiphytic
bromeliads in some localities. Specimens collected
from T utriculata at Vero Beach sent by Frank to
J. K. Hiltunen (Great Lakes Laboratory, Ann Ar-
bor, MI) were identified as reported by Frank &
Lounibos (1987). The species was originally de-
scribed from epiphytic bromeliads in Costa Rica
by Michaelsen (1912), an early discovery by Pic-
ado (1913). It has a wide distribution in the Neo-
tropics. Lopez et al. (2005) in Brazil found that it
is attracted to frogs visiting the bromeliads, and
crawls onto their skin and uses frogs for dispersal.

Arthropoda: Crustacea: Ostracoda: Cytheridae
Metacypris Brady & Robertson
Metacypris maracaoensis Tressler, 1941

This ostracod was initially reported from epi-
phytic bromeliads in Puerto Rico, and was later
found in epiphytic bromeliads in Collier County,
Florida (Tressler 1956). It was collected by Fish,
identified by C. W. Hart (Smithsonian Institution,
Washington, D.C.) reported by Fish (1976); it was
abundant in leaf axils of T fasciculata in Ever-
glades National Park, and less common in other
bromeliads. Lopez et al. (2005) found that Elpid-
ium, another ostracod genus, used phoresy on
frogs for transport from bromeliad to bromeliad in
Brazil, like Dero worms.

Arthropoda: Crustacea: Ostracoda
Podocopa, family unknown, sp. indet. of Fish, 1976

Only juvenile forms of this ostracod were col-
lected and sent to C. W. Hart, who therefore could
not identify them at the family or species level.
They were found in bromeliads of tropical hard-
wood hammocks, often with M. maracaoensis.


Arthropoda: Crustacea: Copepoda: Cyclopidae
Paracyclops Claus
Paracyclops bromeliacola Karaytug & Boxshall, 1998
This copepod, originally described from brome-
liads in Brazil by Karaytug & Boxshall (1998),
was found in a bromeliad in the Florida Keys by
Reid & Hribar (2006) who suggested that it might
have arrived in Florida on ornamental bromeliads
imported from Brazil. They did not identify the
bromeliad in which it was collected. They did not
identify the bromeliads from which 2 other cyclo-
pids were collected in the Florida Keys: Bryocy-
clops muscicola Menzel, and Paracyclops chiltoni
(Thomson). These last 2 species are not believed
to be bromeliad specialists.

Arthropoda: Crustacea: Copepoda:
Phyllognathopodidae
Phyllognathopus Mrazek
Although Phyllognathopus vigueiri (Maupas)
has been found in bromeliad phytotelmata in sev-
eral countries (Frank 1983); it seems to be a gen-
eralist, not a bromeliad specialist. Its finding in
unnamed bromeliads in the Florida Keys was pre-
dictable given that it had been found in other non-
phytotelm habitats elsewhere in Florida (Reid &
Hribar 2006).

Arthropoda: Arachnida: Acari: Histiostomatidae
(formerly Anoetidae)
Anoetus Dujardin
Anoetus sp. of Fish, 1976
Initial identification was made by H. L.
Cromroy (University of Florida) as reported by
Fish (1976). To the best of our knowledge the spe-
cies has not yet been described. If it really belongs
to the genusAnoetus, it may feed on bacteria as do
other species in the genus.

Arthropoda: Insecta: Diptera: Sciaridae
Corynoptera Winnertz
Corynoptera sp. of Fish, 1976
Specimens collected by Fish were identified by
W. A. Steffan (Bishop Museum, Honolulu, HI) as
reported by Fish (1976). The aquatic larvae are
presumed to feed on fungi growing on decaying
leaf litter. To the best of our knowledge the species
has not yet been described.

Arthropoda: Insecta: Diptera: Psychodidae
Alepia Enderlein
Alepia symmetrica Wagner & Hribar, 2005
Fish (1976) reported that aquatic larvae of a
psychodid were abundant in epiphytic bromeliads







Florida Entomologist 91(1)


in some localities in southern Florida. The tenta-
tive identification supplied by F. C. Thompson
(USDA Systematic Entomology Laboratory) was
as an unidentified species of Neurosystasis. How-
ever, specimens apparently of the same species
collected in 1997-2001 and supplied to a specialist
taxonomist were identified as a species ofAlepia
(Frank et al. 2004). The name Alepia symmetrica
Wagner & Hribar was based on specimens from
the Florida Keys. For the present, we assume that
this is the same species that occurs in bromeliads
elsewhere in Florida, and that it has been present
in Florida for a long time as an inhabitant of leaf
axils of native epiphytic bromeliads. It has
adapted to imported, ornamental bromeliads in
urban areas. For lack of evidence, we here treat it
as a precinctive species because we have no way of
knowing whether it occurs elsewhere. We pre-
sume that the larvae feed on submerged leaf litter.

Arthropoda: Insecta: Diptera: Culicidae

Wyeomyia Theobald
Wyeomyia mitchellii (Theobald), 1905
W. vanduzeei Dyar & Knab, 1906

Wyeomyia mitchellii was originally described
from Jamaica, and is known also from other is-
lands of the Greater Antilles, eastern Mexico, and
Florida. Wyeomyia vanduzeei was originally de-
scribed from Florida, and is known also from Cuba,
the Cayman Islands, and Jamaica. Both species
are considered native to Florida. Fish (1976) re-
ported both species. Adults and larvae may be
identified by the key by Darsie & Morris (2003).
Adults of both species are active during daylight
hours (Frank 1983; Frank et al. 1985). Of the two,
W mitchellii is more restricted to shaded habitats
(Frank & O'Meara 1985). Females of both species
use color vision to detect bromeliads in which to
oviposit, although their color preferences differ
slightly (Frank 1985, 1986). They hover over leaf
axils while ovipositing, and eggs of W vanduzeei
are made buoyant by a remarkable sculpted wax-
like coating (Frank et al. 1981). Their typical nurs-
ery plant is T utriculata (Frank & Curtis 1981a),
but they also will develop in other native water-im-
pounding Tillandsia spp. (Fish 1976) and in the in-
sectivorous bromeliad Catopsis berteroniana
(Frank & O'Meara 1984). Larvae filter-feed on
small particles in a nutrient-poor environment
which is enriched by throughfall from tree cano-
pies above. They compete intra- and inter-specifi-
cally for food, and have evolved a remarkable abil-
ity to survive long periods of starvation (Frank
1983). Larvae will not develop in less time than
about 2 weeks-attempts to provide them with a
rich diet to hasten their development in the labora-
tory may prove fatal to them (Frank 1983).
Both of these Wyeomyia mosquitoes have
adapted to the habitat provided by imported, or-


namental bromeliads that usually are cultivated
terrestrially in urban habitats in southern Flor-
ida (Frank et al. 1988). They are sometimes
present in greenhouses and even outdoors in
northern Florida where these plants are grown
beyond the northern limit of native, water-im-
pounding bromeliads.

Culex Linnaeus
Culex (Micraedes) biscaynensis Zavortink & O'Meara,
1999

This species was discovered in imported, orna-
mental bromeliads in Dade County and also was
found in T utriculata and T fasciculata (O'Meara
& Evans 1997). It was described as a new species
(Zavortink & O'Meara 1999) on the grounds that
specimens could not be matched to any known
mosquito species despite resemblance to a species
of the subgenus Micraedes known from the Baha-
mas, Hispaniola, Puerto Rico, and the U.S. Virgin
Islands. One interpretation is that it could be a
species that evolved in isolation in southern Flor-
ida, having the same common ancestor as the
abovementioned Micraedes. Another could be that
it is a species that arrived as a contaminant of im-
ported, ornamental bromeliads, and that its true
origin remains to be discovered. For lack of other
information, we consider it as a species precinc-
tive to Florida.
Immature stages of mosquito species some-
times occur in bromeliads. Toxorhynchites rutilus
(Coquillett) is a treehole specialist but its preda-
cious larvae are sometimes found in Tillandsia
utriculata (Frank et al. 1984) and imported, orna-
mental bromeliads (Frank et al. 1988).Aedes ae-
gypti (L.) and Culex quinquefasciatus Say are not
bromeliad specialists, but they sometimes colo-
nize imported, ornamental bromeliads, especially
those having the impounded water accidentally
enriched by lawn grass clippings (Frank et al.
1988). Aedes bahamensis Berlin was detected in
imported, ornamental bromeliads in southern
Florida but it was not abundant in such habitat,
and is not a bromeliad specialist (O'Meara et al.
1995). After the Asian species Aedes albopictus
(Skuse) was detected in Florida, it began to dis-
place A. aegypti in water-filled containers where
A. aegypti larvae could previously be found. In
places in northern Florida where imported, orna-
mental bromeliads are cultivated, A. albopictus
larvae usurped the phytotelmata provided by
those bromeliads to the extent that it was occu-
pied by mosquito larvae at all (O'Meara et al.
1993). In southern Florida, inroad made byA. al-
bopictus was much more limited and it repre-
sented just a small proportion of the mosquito lar-
vae in ornamental bromeliads-the vast majority
being Wyeomyia (O'Meara et al. 1993). Lounibos
et al. (2003) concluded that competition with bro-
meliad-specialist Wyeomyia was the reason for


March 2008







Frank & Fish: Aquatic Invertebrates in Florida Bromeliads


the low numbers ofA. albopictus in imported, or-
namental bromeliads in southern Florida.

Arthropoda: Insecta: Diptera: Ceratopogonidae

Forcipomyia Meigen
F. (s. str.) seminole Wirth, 1976
F. (Warmkea) fishi Wirth & Soria, 1979
Forcipomyia (Phytohelea) bromelicola (Lutz) 1914

The first 2 species of midge were reported as
unnamed by Fish (1976). Wirth (1976) described
F seminole from adult specimens collected at Vero
Beach. Wirth & de Soria (1979) described F fishi
from specimens collected in T utriculata in
Brevard, Indian River, and Monroe counties.
There is no indication that either of these species
occurs outside Florida. The detection of F bro-
melicola in the Florida Keys results from contam-
ination of imported bromeliads (Grogan & Hribar
2006). In addition to these species, Forcipomyia
(Phytohelea) oligarthra Saunders was reported
from pineapple leaf axils in Highlands County,
Florida, by de Meillon & Wirth (1979). This spe-
cies is known from terrestrial bromeliads
(Ananas and Bromelia) in several countries, but
apparently not from epiphytic bromeliads, so it
cannot be considered native to Florida where
there are no native terrestrial bromeliads.

Arthropoda: Insecta: Diptera: Chirononomidae:
Tanypodinae

Monopelopia Fittkau
Monopelopia tillandsia Beck & Beck, 1966
Monopelopia caraguata Mendes, Marcondes
& de Pinho, 2003.

Monopelopia tillandsia has not yet been re-
ported outside Florida and is considered a precinc-
tive species. The predatory, orange-colored larvae
were recorded from epiphytic Tillandsia spp. by
Beck & Beck (1966), and by Fish (1976). It was
seen in Tillandsia utriculata at Vero Beach and re-
ported by Frank (1983). Monopelopia caraguata,
originally described from Brazil by Mendes et al.
(2003), and discovered in the Everglades by R. Ja-
cobsen (Epler 2007), seems to be a new discovery.
Because we do not know how long it has been
present in Florida, we treat it as a recent arrival.

Arthropoda: Insecta: Diptera: Chirononomidae:
Orthocladiinae

Metriocnemus van der Wulp
Metriocnemus sp. A of Epler, 2001

This species was reported from Florida by Beck
& Beck (1966) and then by Fish (1976) under the
name Metriocnemus abdominoflavatus Picado,
but Epler (2001) stated that was an incorrect


identification. Larvae may be abundant, do not
build cases and are thought to feed on debris.
Genus H of Epler, 2001
A species of this unknown genus was reported
only from bromeliads in Highlands County, Flor-
ida by Epler (2001).

Arthropoda: Insecta: Diptera: Chirononomidae:
Chironominae
Tanytarsus bromelicola Cranston, 2007
Although described from Puerto Rico, from
Guzmania berteroniana (Schultes f.) Mez brome-
liads, this species was also reported from Indian
River County, Florida from Tillandsia sp. (Cran-
ston 2007). Almost certainly it is the unidentified
tanytarsine reported by Fish (1976), who found it
to be the most abundant chironomid in bromeli-
ads. Larvae of this species, with red hemolymph,
are restricted in Florida to T utriculata where
they form transportable cases and feed on micro-
organisms (Fish 1976).
Epler (2001) reported the finding of a larva of
Dicrotendipes leucoscelis (Townes) in a Florida
bromeliad, but this species is widespread in the
eastern USA and is not a bromeliad specialist.

Arthropoda: Insecta: Diptera: Syrphidae
Meromacrus Rondani
Meromacrus sp. of Fish, 1976
Fish (1976) reported an unidentified species of
this genus from bromeliad phytotelmata in Flor-
ida. A few larvae probably of the same genus were
noted by Frank in T utriculata at Vero Beach, and
he reported Fish's observation (Frank 1983). F. C.
Thompson (USDA, Systematic Entomology Labo-
ratory, Washington, DC) is preparing a description
of this species using specimens collected by Fish.

Arthropoda: Insecta: Diptera: Periscelididae
Stenomicra Coquillett (formerly in Aulacigastridae)
Stenomicra sp. of Fish, 1976
Fish (1976) reported predatory aquatic fly lar-
vae identified as Stenomicra by C. W. Sabrosky
(USDA Systematic Entomology Laboratory,
Washington, D.C.). Larvae are dorso-ventrally
flattened, have forked "tails" and are pale, and
were reared to maturity on a diet ofWyeomyia lar-
vae. This species has not yet been described.

Arthropoda: Insecta: Diptera: Muscidae
Neodexiopsis Malloch
Neodexiopsis sp. of Fish, 1976
Specimens collected by Fish were identified by
H. C. Huckett (Cornell University) and reported
by Fish (1976). Larvae are cylindrical, pale, pred-
atory, and were reared to maturity on a diet of







Florida Entomologist 91(1)


Wyeomyia larvae. This species has not yet been
described.

DISCUSSION

That many of the invertebrates discussed here
exist in no habitat other than bromeliads is sup-
ported by the work of Picado (1913). Picado (1913,
pp. 264-274) reviewed data of earlier authors as
well as his own to argue that many bromeliad-in-
habiting invertebrate species are restricted to
bromeliads. Frank & Curtis (1981b) reviewed
published collection records for 241 mosquito spe-
cies whose larvae had been reported from brome-
liads in the Americas south of the U.S.A., reveal-
ing that many had been found only in bromeliad
phytotelmata. Some had been collected also in
water-impounding leaf axils of other plants; con-
versely, some had been found mainly in axils of
other plants, rarely in bromeliads. Corbet (1983)
reviewed the phytotelma-inhabiting Odonata,
distinguishing specialists from generalists and
showing that some species develop only in brome-
liads. These data support the existence of a spe-
cialist bromeliad-inhabiting fauna.
Florida law defines the conservation status of
Florida's native biota without regard to extralim-
ital distributions. Seven of the bromeliad species


attacked by M. callizona are listed as endangered
(two because of attack by M. callizona) and three
more as threatened under Florida law (Florida
Administrative Code 1998). The only precinctive
species among the species under attack, T simu-
lata, has no protected status (Table 1). None of the
specialist invertebrates inhabiting these bromeli-
ads is protected under Florida law. However, pro-
tection under Florida law provides no guarantee
of funding to achieve protection-it just makes
permits necessary for biologists or anyone else to
collect or possess them.
U.S. Federal law, under the Endangered Spe-
cies Act, operates differently. Purportedly, it pays
no attention to species that may be at risk in the
U.S. while having a large population outside the
U.S. It concentrates on species that are precinc-
tive in some part of the USA. Thus, we might
expect that T simulata (and the 5 invertebrates
listed as precinctive in Table 2) would be eligible
for protection under Federal law. The U.S. Fish
and Wildlife Service has not yet accorded them
protected status.
Under the Endangered Species Act, funding is
available for protection of Florida populations
(named as subspecies) of species that have popu-
lations elsewhere, even though these extralimital
populations may be widespread and thriving.


TABLE 2. AQUATIC BROMELIAD-INHABITING SPECIALISTS; (A: ADVENTIVE, RECENT ARRIVAL, PERHAPS AS A CONTAMI-
NANT, C: PROBABLY A PRE-COLUMBIAN ARRIVAL, SO CONSIDERED NATIVE, P: PRECINCTIVE TO FLORIDA; U:
UNIDENTIFIED/UNDESCRIBED).

Occurs outside Florida too
Precinctive
Identity Recent arrival Pre-Columbian ("endemic") Undescribed species

Indet. turbellarian U
Dero superterrenus C
Metacypris maracaoensis C
Indet. podocopan U
Paracyclops bromeliacola A
Anoetus sp. U
Corynoptera sp. U
Alepia symmetrica P
Wyeomyia mitchellii C
Wyeomyia vanduzeei C
Culex biscaynensis P
Forcipomyia seminole P
Forcipomyia fishi P
Forcipomyia bromelicola A
Monopelopia tillandsia P
Monopelopia caraguata A
Metriocnemus sp. A U
Genus H sp. U
Tanytarsus bromelicola C
Meromacrus sp. U
Stenomicra sp. U
Neodexiopsis sp. U

At least the 10 species marked C or P are considered native; most likely the 9 species marked U are also native.


March 2008







Frank & Fish: Aquatic Invertebrates in Florida Bromeliads


Thus, Florida populations of Felis concolor L.
(cougar), Trichechus manatus L. (West Indian
manatee), and Heraclides aristodemus Esper
(dusky swallowtail) have been given the names of
Felis concolor coryi (Bangs) (Florida panther),
Trichechus manatus latirostris (Harlan) (Florida
manatee), and Heraclides aristodemus ponceanus
(Schaus) (Schaus swallowtail). These subspecies
have been declared under the law to have protec-
tion, and are even called "endangered species."
None of the bromeliads listed in Table 1 or inver-
tebrates listed in Table 2 has had Florida subspe-
cies named; we might argue that this is so be-
cause the taxonomists involved have been so
stretched to provide species-level identification
that they have not had time to provide a finer-
meshed classification.
Losses being inflicted by Metamasius callizona
on Florida bromeliad populations also affect their
aquatic invertebrate fauna. Twenty one native
species, consisting of 12 bromeliads and at least 9
(perhaps 19) invertebrates are at risk of extinc-
tion in Florida and in the U.S.A. At least 6 of them
(1 bromeliad and 5 invertebrates) seem to be pre-
cinctive species.
The most important task with the aquatic in-
vertebrates is to get adult specimens into the
hands of expert taxonomists who will identify or
describe them. This task has not changed since the
1970s. It requires collecting living specimens of the
juvenile aquatic organisms and rearing them to
the adult stage. The task is now more difficult than
it was in the 1970s because of loss of bromeliad
populations and because the community of expert
taxonomists is reduced by retirements and deaths.
Readers are requested not to send specimens to
the authors for identification. Instead, please use
the cited works to make your own identifications,
and/or contact expert taxonomists. Conceivably,
by making your chosen taxonomist aware of this
publication (showing the historical background)
you may hasten the identification process. If Flor-
ida authorities list them as endangered and re-
quire permits for their collection, this will only
make more difficult the task of description and
study. The best way to protect the bromeliad-asso-
ciated invertebrates is to control M. callizona.
This paper documents, as far as is now possible,
the identity of the aquatic invertebrates in native
Florida bromeliads in order to highlight the threat
caused by M. callizona. It does not include the geo-
graphic distributional information or much of the
host-plant information or abundance data pro-
vided by Fish (1976). Frank & Thomas (2001) in-
clude an extensive bibliography of aquatic organ-
isms in bromeliad phytotelmata worldwide.

ACKNOWLEDGMENTS

We thank all the taxonomists mentioned in these
pages; without their efforts there would be nothing to


report. We thank the Florida Council of Bromeliad Soci-
eties for current support of technicians in Honduras
who are collecting and rearing material of the biological
control agent, and the South Florida Water Manage-
ment District for current support of a graduate student
working on the project; without that support, the biolog-
ical control program against the weevil would have been
terminated. We thank Tim Andrus (Tallahassee, FL)
and Dennis Giardina (Naples, FL) for accompanying
J. H. Frank on 2 exploratory trips to Guatemala in
search of additional potential biological control agents
for use against M. callizona when there were no grant
funds to pay for their time or expenses. Julieta Bram-
bila kindly prepared the Resumen. Cal Welbourn and
Gary Steck kindly reviewed a draft manuscript.

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Florida Entomologist 91(1)







Shelly et al.: Mating Success of Male Med Flies


MATING SUCCESS OF MALE MEDITERRANEAN FRUIT FLIES FOLLOWING
EXPOSURE TO TWO SOURCES OF (-COPAENE, MANUKA OIL AND MANGO

TODD E. SHELLY, AMY N. COWAN, JAMES EDU AND ELAINE PAHIO
USDA-APHIS, 41-650 Ahiki Street, Waimanalo, HI 96795

ABSTRACT

Recent studies on the Mediterranean fruit fly (medfly), Ceratitis capitata (Wied.), have dem-
onstrated an increase in male mating competitiveness following exposure to particular plant
structures or products, including the fruit and fruit-derived oil of orange trees, the bark and
fruits of guava trees, and ginger root oil. Although it is not known which compounds) was
responsible for the enhanced mating success, all the performance-boosting substances
tested thus far contain the sesquiterpene hydrocarbon a-copaene, and a-copaene tested
alone was found to increase mating success in male medflies. As the concentration of a-co-
paene and other terpenes vary among plant species, it is not known whether exposure to a-
copaene-bearing plants (or their derived oils) will universally influence the mating behavior
of male medflies. The goal of this study was to describe the results of mating trials conducted
after male exposure to 2 previously untested sources of a-copaene, manuka oil (from the
New Zealand manuka tree) and mango fruits from cultivars in Hawaii and Guatemala. Mat-
ing trials conducted in field-cages revealed that exposure to manuka oil significantly in-
creased the mating success of both wild males and mass-reared, sterile males. However,
exposure to mangos had no effect on male mating performance in trials run in Hawaii or
Guatemala. This latter result may have reflected the absence (or presence in very small
amounts) of a-copaene in the mango cultivars tested or a particular mixture of compounds
that diminished or blocked a-copaene's effect on the male medflies.

Key Words: Ceratitis capitata, Tephritidae, manuka oil, mango, mating behavior

RESUME

Estudios actuales sobre la mosca mediterranea del fruto, Ceratitis capitata (Wied.), han de-
monstrado un aumento en la capacidad de los machos para competir en el apareamiento des-
pu6s de ser expuestos a estructuras o products de plants particulares, incluyendo el fruto o
aceite derivado del fruto, la corteza y el fruto del arbol de guajava, y aceite de la raiz del jen-
gibre. Aunque no se sabe cual de estos quimicos compuestos fue responsible para mejorar el
6xito del apareamiento, todas las substancias probadas hasta ahora que aumentan la capaci-
dad para ejecutar el apareamiento contienen el hidrocarburo sesquiterpene a-copaene, y se
encontr6 que las pruebas con solo a-copaene resultaron en un aumento en el exito de aparea-
miento de los machos de la mosca mediterranea. Como la concentraci6n de a-copaene y otros
terpenes varia en las diferentes species de plants, no se sabe si la exposici6n a plants que
contienen a-copaene (o el aceite derivado de ellas) influye universalmente el comportamiento
de apareamiento de los machos de la mosca mediterranea. La meta de este studio fue para
describir los resultados de las pruebas del apareamiento realizadas despu6s de exponer los
machos a 2 fuentes de a-copaene antes no probadas, el aceite de manuka (del arbol manuka
de Nueva Zelanda) y el fruto de variedades de mango de Hawaii y Guatemala. Las pruebas de
apareamiento realizadas enjaulas en el campo mostraran que la exposici6n al aceite de ma-
nuka aumento significativamente el 6xito de apareameinto de machos esteriles tanto salvajes
como criados en masa. Sin embargo, la exposici6n al mango no tuvo ningun efecto sobre la eje-
cuci6n del apareamiento de los machos en pruebas realizadas en Hawaii o Guatemala. Este
iltimo resultado puede reflejar la ausencia (o presencia de muy poca cantidad) de a-copaene
en las variedades de mango probadas o en la mezcla especifica de los quimicos compuestos que
diminy6 o bloqueo el efecto de a-copaene's sobre los machos de la mosca mediterranea.


Recent studies on the Mediterranean fruit fly and (iii) ginger root oil (Zingiber officinale Roscoe)
(medfly), Ceratitis capitata (Wied.), have demon- (Shelly 2001). Although it is not known which
strated an increase in male mating competitive- compounds) is responsible for the enhanced mat-
ness following exposure to particular plant struc- ing success, all the performance-boosting sub-
tures or products, including (i) the fruit and fruit- stances tested thus far contain the hydrocarbon
derived oil of orange trees (Citrus sinensis L) sesquiterpene a-copaene, a powerful attractant to
(Papadopoulous et al. 2001, 2006; Shelly et al. male medflies (Warthen & McInnis 1989; Flath et
2004a), (ii) the bark and fruits of guava trees al. 1994), and a-copaene alone was found to in-
(Psidium guajava L) (Shelly & Villalobos 2004), crease mating success in male medflies (Shelly







Florida Entomologist 91(1)


2001). In light of this latter finding, in particular,
it appears probable that a-copaene, alone or with
other compounds, influenced male mating perfor-
mance following exposure to the various plants
and oils noted above.
The compound a-copaene occurs in a wide
range of plant species, including corn (Kdllner
et al. 2004), wheat (Buttery et al. 1985), oaks
(Vrkocova et al. 2000), and pine trees (Barnola et
al. 1994) as well as many host plants of C. capi-
tata, such as Citrus spp. (Nishida et al. 2000; Dou
2003). As the concentration of a-copaene and re-
lated mono- and sesquiterpenes vary among plant
species, it is not known whether exposure to a-
copaene-bearing plants (or their derived oils) will
universally influence the mating behavior of male
medflies. The goal of this study was to describe
the results of mating trials conducted after male
exposure to 2 previously untested sources of a-co-
paene, manuka oil from the New Zealand manuka
tree, Leptospermum scopariu (Forst. & Forst.) and
mango (Mangifera indica L.) fruits from cultivars
in Hawaii and Guatemala. In addition, the rela-
tive attraction of males and females to manuka oil
was compared in field-cage trials.

MATERIALS AND METHODS

The methods employed are similar to those de-
scribed previously (Shelly 2001; Shelly et al.
2004a). Consequently, an abbreviated description
follows, and the aforementioned studies should be
consulted for additional details. Also, the single
experiment (involving mango exposure) con-
ducted in Guatemala followed the same basic pro-
cedure used in Hawaii, consequently only meth-
ods unique to Guatemala are noted.

Hawaii: Study Insects

Because of low availability of wild flies, we
used flies from recently established colonies
(REC) derived from 500-1000 adults reared from
field-collected fruits. For experiments involving
manuka oil, the wild flies were derived from coffee
berries (Coffea arabica L.) from the island of
Kauai, and the flies tested were 3-4 generations
removed from the wild. For experiments involving
mango, the wild flies were derived from Jerusa-
lem cherry (Solanum capsicum L.) from the is-
land of Hawaii, and the flies tested were 5-6 gen-
erations removed from the wild. Adults of both
colonies were provided with a sugar-protein mix-
ture and water and a perforated vial for oviposi-
tion. Eggs were placed on standard larval diet
(Tanaka et al. 1969), and pupae were sifted from
vermiculite placed beneath the diet containers.
Adults used in the mating trials were separated
by sex within 24 h of eclosion and kept in screen-
covered, plastic buckets (5-L volume, with cloth-


sleeved-opening on side for transferring flies)
with ample food and water.
Mass-reared, sterile males from a genetic sex-
ing (temperature sensitive lethal, tsl) strain were
obtained from the California Department of Food
and Agricultural Fruit Fly Rearing Facility
(Waimanalo, HI). The tsl males were dyed fluores-
cent pink and irradiated as pupae 2 d before eclo-
sion and were maintained as adults in the same
manner as the REC flies.

Manuka Oil-Source and Exposure Protocol for Mating
Trials

Douglas et al. (2004) identified over 40 com-
pounds in the essential oils of the New Zealand
manuka, including many terpenoids. The oil used
in the present study was obtained from Coast Bi-
ologicals Limited (Auckland, New Zealand) and,
according to that company's specifications, con-
tained 42-48 g/L of a-copaene. This concentration
is approximately 1 order of magnitude greater
than that recorded for a-copaene in ginger root oil
(0.4%, Shelly 2001).
We conducted 5 experiments investigating the
effect of manuka oil on male mating success dur-
ing Apr-Jun 2006. REC flies were used exclusively
in the first 2 experiments with treated REC males
exposed to 100 pL (experiment 1) or 10 pL (exper-
iment 2), competing against non-exposed (control)
REC males for matings with REC females. In the
remaining experiments, treated tsl males were ex-
posed to manuka oil and competed against (non-
exposed) REC males for matings with REC fe-
males. Doses of 100 and 10 pL were used to expose
tsl males in experiments 3 and 4, respectively. In
experiment 5, treated tsl males were also exposed
to 100 pL but were prevented from physically con-
tacting the oil-bearing source. For experiments 3-
5, corresponding controls were run in which con-
trol, non-exposed tsl males competed against (non-
exposed) REC males for REC females, thus allow-
ing assessment of the impact of manuka oil expo-
sure on the mating competitiveness of tsl males.
For exposure, we transferred 60 sexually ma-
ture males (REC males: 7-10 d old; tsl males: 5-8
d old) to a new bucket and, and using a microcap-
illary pipette, applied the oil to a small paper disc
(5 mm diameter) resting in an aluminum-foil-
lined Petri dish, which was then placed on the
floor of the male-holding bucket. Exposure started
at 0900 h and continued for 1 h. Aside from the fi-
nal experiment, the oil-laden disk was uncovered
during exposure. The behavior of males was not
monitored systematically during exposure peri-
ods, but in frequent checks males were never seen
touching the paper disk, an observation consis-
tent with prior studies involving a-copaene or a-
copaene-containing oils (Nishida et al. 2000;
Shelly 2001). Rather, the oil acted as an arrestant,
and males were generally quiescent. Nonetheless,


March 2008







Shelly et al.: Mating Success of Male Med Flies


in the final experiment, we covered the Petri dish
with nylon screening to guarantee that males did
not contact the oil-laden paper disk. Upon re-
moval of the oil, food and water were added to the
bucket, and males were held for testing the follow-
ing day. In all instances, the exposure procedure
was conducted in an isolated room to prevent in-
advertent exposure of other flies.

Mangos-Source and Exposure for Mating Trials

The mangos used for medfly exposure were ob-
tained from trees of the 'Momi-K' and'Pope' variet-
ies at the University of Hawaii Agricultural Exper-
iment Station (Waimanalo, HI; Warner 1972).
Trace amounts of a-copaene were present in the
peel of fruits (n = 5) sampled from these trees, but
quantitative data on concentration is lacking (F. X.
Webster, personal communication). Several thou-
sand cultivars of mango exist (Nakasone & Paull
1998), and their volatile components vary consid-
erably in composition and concentration (see refer-
ences below). However, monoterpene and sesquit-
erpene hydrocarbons are the major volatile compo-
nents of most mango cultivars, particularly among
New World varieties, and may represent 70-90% of
the total volatiles (Winterhalter 1991). A (non-ex-
haustive) survey of published studies revealed
that, of 36 cultivars analyzed, 80% (29/36) contain
a-copaene, usually in concentrations of 0.01-0.12
mg/kg (MacLeod & De Troconis 1982; Engel &
Tressl 1983; MacLeod & Pieris 1984; MacLeod &
Snyder 1985; Bartley & Schwede 1987; MacLeod
et al. 1988; Idstein & Schreier 1985; Sakho et al.
1985; Cosse et al. 1995; Malundo et al. 1996, 1997;
Ol1 et al. 1998; Hernandez-Sanchez et al. 2001;
Nair et al. 2003; Lalel et al. 2003; Zhu et al. 2003;
Lebrun et al. 2004; Mahattanatawee et al. 2005;
Pino et al. 2005; De Lourdes Cardenal et al. 2005).
Even in those cases where a-copaene was not de-
tected, a large number of related terpenes are in-
variably reported, and some of these (e.g., p-
cymene and limonene) are known to be attractive
to medfly males (Herandez-Sanchez et al. 2001) or
to elicit electroantennographic responses of medfly
males (p-caryophyllene, Cosse et al. 1995). In sum,
although quantitative chemical analyses are not
available, we know that the mango fruits used for
medfly exposure contained a rich mixture ofterpe-
noid compounds, including a-copaene.
We ran 4 experiments in Hawaii examining the
effect of mango fruit exposure on male mating
success during Apr-May 2002. REC flies were
used exclusively in the first 2 experiments, with
treated, mango-exposed REC males competing
against control, non-exposed REC males for mat-
ings with REC females either 1 d (experiment 6)
or 3 d (experiment 7) after fruit exposure. In the
remaining experiments, treated tsl males were ex-
posed to ripe mango fruits and competed against
(non-exposed) REC males for matings with REC


females either 1 d (experiment 8) or 3 d (experi-
ment 9) after fruit exposure. For experiments 8
and 9, corresponding controls were run in which
control, apple-exposed tsl males competed against
(non-exposed) REC males for REC females, thus
allowing assessment of the impact of mango expo-
sure on the mating competitiveness of tsl males.
For exposure, we transferred 60 sexually ma-
ture males to a screen cage (30 cm cube) and in-
troduced 2 ripe mangos (fruits from the 2 culti-
vars used were not distinguished). Prior to use,
we made 5 shallow cuts (2-4 cm long) into the skin
of all fruits using a scalpel; a-copaene occurs in
both the skin and pulp of mango fruits (Lalel et al.
2003). Exposure started at 0900 h and continued
for 4 h. Upon removal of the fruits, food and water
were added to the cage, and males were held until
testing 1 or 3 d later. Control tsl males were han-
dled in the same manner except that they were
presented with 2 Granny Smith apples (Malus
sylvestris Mill.) instead of mangos. Mango- and
apple-exposure were performed in separate rooms
to avoid aromatic 'contamination'.

Mating Trials

Mating trials were conducted at the USDA-
ARS laboratory in Honolulu and followed the
same protocol for experiments involving exposure
to manuka oil or mangos. In all cases, we released
50 males of each competing type and 50 REC fe-
males (8-13 d old) at 0800 h in nylon-screen field
cages containing 2 artificial trees and collected
mating pairs over the next 4 h. In experiments in-
volving REC males exclusively, treated and con-
trol individuals were marked 2-4 d before testing
(in all cases, treated males were marked prior to
oil or fruit exposure) with a dot of enamel paint on
the thorax. In experiments involving tsl males,
mated males were examined under a UV light
and identified by the presence (tsl) or absence
(REC) of pink dye. On a given test day, we ran 4
tents simultaneously. For experiments involving
REC males exclusively, each cage contained
treated and control REC males, and for experi-
ments involving tsl males, 2 cages contained
treated tsl males and 2 cages contained control tsl
males competing against REC males. The partic-
ular cages used for treated and control tsl males
were alternated between successive test days.
Comparisons of mating numbers were made
with a t-test for pair wise comparisons and
ANOVA for multi-sample tests as assumptions of
normality (tested by using the Kolmogorov-
Smirnov distribution with Lillefors correction)
and homoscedasticity (tested by Levene's median
test) were met in all cases (with only 2 exceptions
in which case data were log10 transformed). Where
comparisons involved proportions, values were
arcsine transformed. Statistical tests were per-
formed with SigmaStat (Version 2.0).







Florida Entomologist 91(1)


Manuka Oil-Attraction of Males and Females in Field
Cage Trials

The attraction ofmedflies to manuka oil was ex-
amined by comparing the capture of males and fe-
males (from the coffee-derived REC described
above) to manuka oil- versus water-baited Jackson
traps suspended in the canopy of the artificial trees
in the same field cages used in the mating trials. In
each cage, we suspended 2 Jackson traps with
sticky inserts. Each trap contained a paper disk
near the center of the insert, and in 1 trap this disk
contained 100 pL of manuka oil, and in the other
the disk contained 100 pL of water. For a given
field cage, the oil- and water-containing traps were
placed at the same locations in all trials. On a
given test day, 100 males or 100 females were re-
leased in a cage (2 cages per sex per day) at 0900 h,
and traps were collected and scored 3 h later. The
sex released in a given cage was alternated be-
tween successive test days. Tests were run in Jun-
Jul 2006; a total of 8 replicates were run per sex.
Pair wise comparisons were made with the t-test
(raw data) as parametric assumptions were met.

Guatemala

A single experiment assessing the effect of
mango exposure on male mating success was con-
ducted during Mar 2003 in Guatemala. Wild flies
reared from field-collected coffee were used exclu-
sively, and individuals of both sexes were 9 d old
when tested. Treated males were placed in screen
cages along with 2 ripe mangos (variety un-
known) for 3 h (0900-1200 h) on the day preceding
the mating trial; control males were not exposed
to fruit of any type. Treated and control males
were marked with paint as described above 2 d
before testing. Mating trials were conducted in
field cages erected over individual coffee plants at
Finca San Augustin, near Guatemala City. In
each field cage, we released 100 treated males,
100 control males, and 100 females at 0700 h and
collected mating pairs over the next 5 h.

RESULTS


Hawaii: Mating Trials


(oil-exposed) tsl males. However, in all 3 cases, the
treated tsl males obtained a significantly greater
number of matings than the control (non-exposed)
tsl males (experiment 3: t = 7.0, P < 0.001; experi-
ment 4: t = 3.1, P < 0.01; experiment 5: t = 7.1, P <
0.001). Correspondingly, in all 3 cases, the treated
tsl males accounted for a significantly greater pro-
portion of the total matings than the control (non-
exposed) tsl males (experiment 3: t = 6.9, P <
0.001; experiment 4: t = 3.2, P < 0.01; experiment
5: t = 4.4, P < 0.001). Among treated tsl males,
there was no detectable effect of dose or oil-acces-
sibility (covered or not) on mating success; there
was no significant variation among treated tsl
males in experiments 3-5 in either the numbers
(F2 21 = 2.3, P > 0.05, ANOVA) or proportions (F2 21
= 0.85, P > 0.05, ANOVA) of matings obtained.
In contrast to the manuka oil, exposure to
mangos had no apparent effect on the mating suc-
cess of REC or tsl males. In the experiments in-
volving REC males exclusively (experiments 6
and 7), there was no difference in the numbers of
matings obtained by mango-exposed and non-ex-
posed males either 1 or 3 d after treatment, and
fruit-exposed and non-exposed males accounted
for approximately 50% of the total matings. In the
experiments involving REC and tsl males (exper-
iments 8 and 9), REC males obtained significantly
more matings than mango-exposed tsl males, and
there was no significant difference between
mango- and apple-exposed tsl males in either the
number (experiment 8: t = 0.4; experiment 9: t =
0.9) or proportion (experiment 8: t = 0.5, experi-
ment 9: t = 0.4, P > 0.05 in all cases).

Attraction to Manuka Oil

Significantly greater numbers of males than fe-
males were captured in traps baited with manuka
oil (41.2 3.1 versus 5.5 + 2.1, respectively, (mean
SE), t = 9.0, P < 0.001) or water (12.0 2.2 ver-
sus 3.3 0.9, respectively, P < 4.2, P < 0.001). Sig-
nificantly more males were captured in traps
baited with manuka oil than water (t = 7.3, P <
0.001), while for females there was no significant
difference between trap types (t = 1.6, P > 0.05).


Guatemala


In tests involving REC males exclusively (ex-
periments 1 and 2), exposure to manuka oil in-
creased mating success for both doses tested (Table
1A). In fact, the mating frequencies of treated REC
males were nearly identical for the 2 doses, both in
terms of the number (t = 0.2, P > 0.05) and the pro-
portion (t = 0.4, P > 0.05) of matings obtained.
Similarly, in experiments involving REC and
tsl males (experiments 3-5), exposure to manuka
oil enhanced the mating success of the tsl males
(Table 1B). In all 3 experiments, REC males
achieved significantly more matings than treated


Exposure to mangos had no effect on male mating
success in the single experiment run in Guatemala.
On average, mango-exposed males obtained 31.0
2.1 matings (mean SE) compared to 32.5 1.4 for
control, non-exposed males (t = 0.6, P > 0.05, n = 6).

DISCUSSION

Consistent with tests involving ginger root oil
(Shelly 2001; Shelly et al. 2002, 2003, 2004b) and
orange oil (Shelly et al. 2004a, 2007), exposure to
manuka oil enhanced mating success in experi-


March 2008







Shelly et al.: Mating Success of Male Med Flies


TABLE 1. RESULTS OF MATING TRIALS CONDUCTED IN HAWAII TESTING THE INFLUENCE OF MANUKA OIL WITH (A) REC
MALES EXCLUSIVELY OR (B) REC AND tsl MALES. VALUES ARE MEANS SE. FOR A GIVEN EXPERIMENT, t VAL-
UES REFER TO COMPARISONS MADE BETWEEN (A) TREATED AND CONTROL REC MALES OR (B) REC MALES AND
TREATED OR CONTROL tsl MALES. TWELVE REPLICATES WERE CONDUCTED FOR EXPERIMENTS 1 AND 2, AND
8 REPLICATES WERE CONDUCTED FOR EXPERIMENTS 3-5.

A. REC males
Experiment Male type Matings per replicate t' % Matings treated males

1 Treated, 100 il oil 20.1(1.5)
Control, non-exposed 13.7(1.9) 2.6* 60.4
2 Treated, 10 il oil 20.5 (1.2)
Control, non-exposed 14.2 (0.8) 4.6*** 59.0

B. REC-tsl males
Experiment Male type Matings per replicate t % Matings tsl males

3 REC, non-exposed 20.7 (1.7)
Treated tsl, 100 p1 oil 14.5 (0.9) 3.2** 41.2
REC, non-exposed 21.7 (1.8)
Control tsl, non-exposed 4.7 (1.7) 6.4*** 17.7
4 REC, non-exposed 18.9 (2.7)
Treated tsl, 10 p1 oil 10.3 (2.1) 2.5* 35.3
REC, non-exposed 24.9 (2.6)
Control tsl, non-exposed 3.0 (0.9) 7.8*** 10.7
5 REC, non-exposed 19.3 (2.5)
Treated tsl, 100 p1 oil-ve" 11.1(1.3) 3.5** 36.5
REC, non-exposed 24.0 (2.7)
Control tsl, non-exposed 3.6 (0.5) 7.4*** 13.0

Significance levels: *P < 0.05, **P < 0.01, ***P < 0.001.


ments with wild-like or tsl males. Increased mat-
ing success was observed even when the exposed
males were prevented from contacting the
manuka oil, revealing that (as also noted for the
other oils tested) aroma alone was sufficient to
boost mating performance. Despite a much higher
concentration of a-copaene (~10-fold greater),
manuka oil enhanced the mating frequency of tsl
males to about the same level as ginger root oil. In
the present study, manuka oil increased mating
frequency from 11-18% for control tsl males to 35-
41% for treated tsl males, whereas the corre-
sponding increases (from control tsl to treated tsl
proportion of total matings in competition with
wild males) for tests involving ginger root oil were
16% to 30% (Shelly et al. 2002), 16% to 39%
(Shelly et al. 2002), and 19% to 40% (Shelly et al.
2003) and for a test involving orange oil was 26%
to 43% (Shelly et al. 2007). The greatest increase
recorded thus far, in fact, has been noted for gin-
ger root oil, where the relative mating success in-
creased from 23-27% for control tsl males to 43%
- 56% for treated tsl males in a series of tests in-
volving wild Hawaiian flies (Shelly et al. 2004b).
The finding that males were more attracted to
manuka oil than females was also recorded for
ginger root oil (Shelly & Pahio 2002).


Although the underlying mechanism remains
unknown, studies conducted in a large field enclo-
sure (Shelly 2001) and in a laboratory wind-tun-
nel (Papadopoulos et al. 2006) suggest that expo-
sure to ginger root or orange oil (and presumably
manuka oil as well) does not affect the attractive-
ness of the male sex pheromone to females. In-
stead, preliminary tests suggest that the aroma of
ginger root oil interacts with the male exoskele-
ton in some way to produce a scent attractive to
females. Females whose antennae were surgically
removed do not discriminate between ginger root
oil-exposed males and non-exposed males. How-
ever, males whose antennae were removed prior
to exposure to ginger root oil have a mating ad-
vantage over intact males not given access to the
oil. These results suggest that female preference
is based on olfactory cues associated with exposed
males but that male emission of these preferred
cues does not depend on male ability to smell (and
internally process) the oil aroma. Whether tests
involving orange or manuka oil would yield the
same results remains unknown.
In contrast to the manuka oil, exposure to ripe
mangos did not boost male mating success in tests
conducted in Hawaii or Guatemala. The absence
of mating enhancement may have reflected very







Florida Entomologist 91(1)


March 2008


TABLE 2. RESULTS OF MATING TRIALS CONDUCTED IN HAWAII TESTING THE INFLUENCE OF MANGOS WITH (A) REC
MALES EXCLUSIVELY OR (B) REC AND tsl MALES. VALUES ARE MEANS SE. FOR A GIVEN EXPERIMENT. VAL-
UES OF T REFER TO COMPARISONS MADE BETWEEN (A) TREATED AND CONTROL REC MALES OR (B) REC MALES
AND TREATED OR CONTROL tsl MALES. TEN REPLICATES WERE CONDUCTED FOR EXPERIMENTS 6-9.

A. REC males
Experiment Male type Matings per replicate t' % Matings treated males

6 Treated, mangos, 1 d pre-test 12.7 (1.1)
Control, non-exposed 12.3 (0.8) 0.3NS 50.8
7 Treated, mangos, 3 d pre-test 11.4 (0.8)
Control, non-exposed 12.2 (0.9) 0.1NS 48.3

B. REC-tsl males
Experiment Male type Matings per replicate t % Matings tsl males

8 REC, non-exposed 21.6 (2.4)
Treated tsl, mangos, 1 d pre-test 7.3 (0.9) 6.2*** 25.3
REC, non-exposed 22.5 (1.6)
Control tsl, apples, 1 d pre-test 6.9(1.1) 6.6*** 23.5
9 REC, non-exposed 19.9 (2.2)
Treated tsl, mangos, 3 d pre-test 4.4 (0.4) 7.2*** 18.1
REC, non-exposed 24.7 (2.5)
Control tsl, apples, 3 d pre-test 6.5 (0.6) 6.9*** 20.8

'Significance levels: NS-not significant (P > 0.05), ***P < 0.001.


small amounts of a-copaene in the mango culti-
vars tested or a particular mixture of compounds
that diminished or blocked a-copaene's effect on
the male medflies, or absence of another com-
pound(s) that acts synergistically with a-copaene
to promote male mating ability. Consequently, we
tentatively conclude that exposure to a-copaene-
containing fruits does not'automatically' result in
increased mating success of male medflies.

ACKNOWLEDGMENTS

We thank Bill Courtney for supplying the manuka oil,
Mindy Teruya for assistance in Hawaii, and Pedro Ren-
don, Felipe Jeronimo, Felix Acajabon, Carlos Dimas,
Pablo Matute, and Rolando Santos for help in Guatemala.

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Florida Entomologist 91(1)


March 2008


SYNONOMY OF FIVE SCIRTOTHRIPS SPECIES
(THYSANOPTERA: THRIPIDAE) DESCRIBED FROM AVOCADOS
(PERSEA AMERICANA) IN MEXICO

MARK S. HODDLE1, LAURENCE A. MOUND2, PAUL F. RUGMAN-JONES' AND RICHARD STOUTHAMER1
'Department of Entomology, University of California, Riverside, CA 92521, USA

2Honorary Research Fellow, CSIRO Entomology, GPO Box 1700, Canberra, ACT 2601, Australia

ABSTRACT

The holotypes of Scirtothrips aguacatae, S. kupandae, S. manihotifloris, S. tacambarensis,
and S. uruapaniensis were examined and compared with specimens of Scirtothrips perseae
from Mexico, Guatemala, and California. The chaetotaxy of the pronotum and head of each
of these 5 holotypes was found to fall within the range observed on specimens identified as
S. perseae based DNA analyses and subsequent slide mounting and morphological examina-
tion of the body surface of specimens from which analyzed DNA was extracted. As a result
of morphological examination and complementary DNA analyses, these 5 species are con-
sidered synonyms of S. perseae. This synonomy should reduce potential quarantine disputes
over avocado imports from Mexico that could arise from concerns raised over the large num-
ber of Scirtothrips species previously considered as pests of avocados in Mexico that might
inadvertently accompany imports.

Key Words: biosecurity, California, Mexico, Persea americana, Scirtothrips species, synon-
omy, quarantine

RESUME

Los holotipos de Scirtothrips aguacatae, S. kupandae, S. manihotifloris, S. tacambarensis y
S. uruapaniensis fueron examinados y comparados con especimenes de Scirtothrips perseae
de Mexico, Guatemala y California. Se encontr6 que la quetotaxia del pronoto y cabeza de
cada uno de los 5 holotipos estaba entire el rango observado en especimenes identificados de
S. perseae basado en el andlisis de ADN y la subsecuente examinaci6n morfol6gica de la su-
perficie del cuerpo de los especimenes montados en places de vidrio que fueron usados para
dicho andlisis de ADN. Como resultado de la examinaci6n morfol6gica y los andlisis de ADN
complementarios, se consider que estas 5 species son sin6nimos de S. perseae. Esta sin6-
nimia debe reducir las disputes potenciales de cuarantena de aguacates importados de
Mexico que pueden presentarse por la preocupaci6n de un alto numero de species de Scir-
tothrips considerados anteriormente como plagas de aguacate que pueden acompafiar invo-
luntariamente los aguacates importados de Mexico.


The genus Scirtothrips Shull 1909 (Thysan-
optera: Thripidae) consists of very small active
insects typically less than 1.5 mm in length and
often pale yellow in color. Typically, these thrips
breed and feed on young foliage but can occasion-
ally be found in flowers (Hoddle & Mound 2003).
Often large populations of a single species are
taken from a single host plant, and it is very un-
common to find a mixture of several Scirtothrips
species co-inhabiting a single host plant. This eco-
nomically important genus includes several spe-
cies that are serious pests of unrelated annual
and perennial fruits, vegetables, and ornamental
crops. Moreover, some of these species have dem-
onstrated a high invasion potential, and are a
serious quarantine concern for many countries
(Mound & Palmer 1981; Hoddle & Mound 2003).
The genus Scirtothrips includes around 100 de-
scribed species, and 32 of these were described pri-
marily from avocados Persea americana Miller


(Lauraceae) and mangos Mangifera indica L.
(Anacardiaceae) in Mexico (Johansen & Mojica-
Guzman 1998). Species in this genus are difficult to
identify because morphological characteristics (e.g.,
number and arrangement of pronotal setae) are
highly variable within species, even among mem-
bers of populations collected at the same time from
the same host plant (Hoddle & Mound 2003). Addi-
tionally, many species have been described from
distorted, uncleared specimens, and the resultant
iridescence from body contents obscures important
details on the body surface that are needed for spe-
cies identification. To fully appreciate intra- and in-
terspecific morphological variation in Scirtothrips,
it is essential to remove the body contents so that
important character states, such as surface sculp-
turing, distribution patterns of microtrichia and
small setae, can be seen readily. Consequently, ex-
cellent slide mounted material is needed for taxo-
nomic identification of Scirtothrips species.







Hoddle et al.: Synonomy of Five Scirtothrips Species from Mexico


For descriptions of new Scirtothrips species a
reasonable series of cleared specimens is needed
to assess intraspecific variation before meaning-
ful and useful comparisons across species groups
can be successfully attempted (Hoddle & Mound
2003; Mound & zur Strassen 2001). Superior
specimen preparation is especially important to
ensure accuracy and high quality detail for de-
scriptions of new pest species from economically
important crops like avocados and mangos in or-
der to minimize the chances of inaccurate deter-
mination of new species. This is important be-
cause importing countries may impose unneces-
sary quarantine restrictions to minimize the risk
of acquiring new pest species that have been inac-
curately determined and described from poorly
prepared specimens. Quarantine blockades of this
kind are reasonable and should be expected. How-
ever, disputes may be unnecessary if the de-
scribed species at the center of quarantine argu-
ments have poor taxonomic accuracy and low bio-
logical validity.
Scirtothrips perseae Nakahara is the primary
thrips pest of avocados in California U.S.A., caus-
ing millions of dollars ($US) in crop loses and in-
creased management costs annually (Hoddle et al.
2003). At time of discovery in California in 1996,
this pest was an undescribed species and its coun-
try of origin unknown. Subsequent detailed study
of morphology and comparison to known Scirto-
thrips species in North and Central America re-
sulted in the determination that this was a new
species, which led to the description and naming
of this pest as S. perseae (Nakahara 1997).
Because of the severe economic impact S. per-
seae has had on Californian avocado production,
exploration for this pest was undertaken in neigh-
bouring countries with avocado industries. The ob-
jectives were to determine the home range of this
pest, to prospect for natural enemies, and to collect
material for DNA analyses to determine species
limits and to more accurately pinpoint the area of
origin of this pest within the delineated home
range. The morphological examination of approxi-
mately 800 slide-mounted specimens, collected
during surveys in Mexico and Guatemala, revealed
that S. perseae is native to high altitude areas in
these 2 countries, and appears to be extremely host
specific. It has been found only in California, Mex-
ico, and Guatemala, and the only known breeding
host is P americana, the avocado. Using DNA tech-
niques, a molecular key to pest species of Scirto-
thrips was developed (Rugman-Jones et al. 2006),
microsatellites for S. perseae were characterized
(Rugman-Jones et al. 2005), and results of micro-
satellite and mitochondrial DNA analyses have in-
dicated that the area of origin for the source popu-
lation that invaded California was most likely
Coatepec-Harinas in Mexico (Rugman-Jones et al.
2007). Complementary DNA analyses of 2 gene re-
gions (COI and D2) have indicated that widely sep-


arated and isolated populations of Scirtothrips col-
lected from avocados throughout Mexico and Gua-
temala represent just the 1 species, S. perseae
(Rugman-Jones et al. 2007).
In the light of these findings, the description by
Johansen & Mojica-Guzman (1998) of 5 species of
Scirtothrips from avocados (S. aguacatae, S. ku-
pandae, S. manihotifloris, S. tacambarensis, and S.
uruapaniensis) is perplexing. With the recent le-
galization of fresh avocado imports into California
from Mexico the risk of quarantine disputes be-
tween the U.S.A. and Mexico over pest species is
likely to increase. Consequently, the high number
of putative native Scirtothrips species infesting av-
ocados described by Johansen & Mojica-Guzman
(1998) could possibly cause quarantine concerns
for countries importing fresh Mexican avocados.
Johansen & Mojica-Guzman (1998) separated
the 5 species indicated above on the basis of dif-
ferences in the arrangement of setae on the
pronotum. These 5 species were included within a
"citri-assemblage" of 14 species of which 11 were
described as new species. Membership in this
"citri-assemblage" was based on the median setae
on the pronotum arising in "a straight line, either
continuous or with a median gap". This condition
was contrasted with these setae arising "with 1-2
posterior displaced setae". Mound & zur Strassen
(2001) pointed out that the number and position
of the median setae on the pronotum was variable
among specimens of S. perseae from California,
and suggested that the validity of several of the
species described from Mexico needed further
substantiation. The purpose of this paper is to re-
port new observations on the original specimens
of the 5 Scirtothrips species described from avoca-
dos in Mexico, and to consider the biological real-
ity of these species.

MATERIALS AND METHODS

Material Examined

Scirtothrips aguacatae Johansen and Mojica-
Guzman: holotype female, Mexico, Michoacan,
Tacambaro, May 16, 1991, in flowers of Manihot
aesculifolia.
Scirtothrips kupandae Johansen and Mojica-
Guzman: holotype female, Mexico, Michoacan,
Tacambaro, May 16, 1991, in flowers of Manihot
aesculifolia.
Scirtothrips manihotifloris Johansen and
Mojica-Guzman: holotype female, Mexico, Micho-
acan, Tacambaro, May 16, 1991, in flowers of
Manihot aesculifolia.
Scirtothrips tacambarensis Johansen and
Mojica-Guzman: holotype female, Mexico, Micho-
acan, Tacambaro, May 16, 1991, in flowers of
Manihot aesculifolia.
Scirtothrips uruapaniensis Johansen and
Mojica-Guzman: holotype female, Mexico, Micho-







Florida Entomologist 91(1)


acan, km 7 on road Uruapan-Nuevo San Juan
Parangaricutiro, Sep 1-4, 1992, from young foli-
age of P americana.
Paratypes of these 5 species have not been re-
examined, but most of the paratypes were col-
lected from P. americana (Johansen & Mojica-
Guzman 1998).
In addition to these holotypes, the following
slide mounted specimens of S. perseae have been
studied: California 292; Mexico 361; Guatemala
411 (Hoddle et al. 2002; Rugman-Jones et al.
2007). The exoskeletons of specimens of S. perseae
collected from California, Mexico, and Guatemala
from which DNA had been extracted and analyzed
were subsequently mounted onto slides for mor-
phological examination following methods out-
lined by Rugman-Jones et al. (2006, 2007). The
pronotum of the holotypes of S. agucatae, S. ku-
pandae, S. manihotifloris, S. tacambarensis, and
S. uruapaniensis were digitally photographed
with a Zeis Axioskop microscope at 400x magnifi-
cation and the images compiled with automontage
software (Syncroscopy, Synoptic, U.K.) (Fig. 1A-E).
Photography and image compilation was repeated
for 4 specimens of Scirtothrips collected from avo-
cados in Uruapan, Mexico, from which DNA was
extracted, analyzed, and confirmed as being from
S. perseae. The resultant cadavers from DNA ex-
traction were cleared in NaOH, and subjected to a
dehydrating ethanol series and clove oil before
mounting in balsam on glass slides (Mound &
Marullo 1996 for details on slide mounting thrips).
The photographs ofS. perseae (Fig. 2A-D) are used
here for comparison to the 5 holotype species de-
scribed from Mexico (Fig. 1A-E).

RESULTS AND DISCUSSION

It is important to note that the holotypes of the
first 4 of these new Scirtothrips species, S. agua-
catae, S. kupandae, S. manihotifloris, and S.
tacambarensis, were collected on the same date,
at the same locality, and from the same plant spe-
cies. As noted previously, it is very unusual to col-
lect more than 2 different species of Scirtothrips
together on the same plant at the same time.
Based on the identification key provided by Jo-
hansen & Mojica-Guzman (1998), the holotypes
of S. aguacatae and S. manihotifloris will key to
S. citri, in view of the arrangement of pronotal se-
tae (i.e., pronotal median transverse setal row
regularly continuous) (Fig. 1A, C) and position of
pair III of the ocellar setae (i.e, ocellar setae III
arising on the margin of the ocellar triangle).
However, S. citri, the Californian citrus thrips,
does not have the tergal antecostal ridges dark as
in these specimens. The variation in position of
setae is apparent in the original illustrations pro-
vided by Johansen & Mojica-Guzman (1998). For
example, the illustrations of both S. aguacatae
and S. manihotifloris (see original Figs. 18 and 20


of the holotypes in Johansen & Mojica-Guzman
1998), indicate that 1 ocellar seta is on the mar-
gin of the ocellar triangle but the other is within
the triangle. The pronotal chaetotaxy of these 2
holotypes falls (see Fig. 18 S. manihotifloris and
Fig. 20 S. aguacatae in Johansen & Mojica-
Guzman 1998) within the range of variation
found in specimens of S. perseae collected from
avocados in California, Guatemala, and Mexico,
which have been confirmed as being S. perseae by
DNA analyses (Fig. 2A-D). Further, comparison
of the position of ocellar setae III of these 2 holo-
types also show variation that is consistent with
S. perseae (see original Figs. 10 and 127 for S. per-
seae in Johansen & Mojica-Guzman 1998). Conse-
quently, there is no reason to consider that S.
aguacatae and S. manihotifloris represent any
species other than S. perseae.
Scirtothrips kupandae was distinguished be-
cause the pronotum has a wide gap (21.5 mm) in
the transverse row of setae, and the pronotum
was stated to be "without subanteromarginal se-
tae". However, examination of the holotype has
confirmed that the original illustration Fig. 11 of
Johansen & Mojica-Guzman (1998) is correct in
showing the presence of 2 subanteromarginal se-
tae (Fig. 1B). No other characters have been ob-
served on this holotype that would distinguish S.
kupandae from S. perseae.
Scirtothrips tacambarensis was distinguished
by Johansen & Mojica-Guzman (1998) because of
the presence of 4 setae in the median transverse
row on the pronotum, and also the presence of 1
subanteromarginal seta (Fig. 1D). Johansen &
Mojica-Guzman (1998) provide no clear definition
or illustration of what constituted either the me-
dian row of setae, or the subanteromarginal setae.
Further, the precise position of the pronotal setae
is highly variable between individual Scirtothrips
from the same population (Fig. 2A-D). Thus, S.
tacambarensis can not be distinguished morpho-
logically from S. perseae.
Scirtothrips uruapaniensis was based on 2
specimens, the holotype listed above and a female
paratype taken from Mangifera. This species was
distinguished because there is a broad gap in the
transverse row of median setae on the pronotum,
that is, there are only 2 setae in this transverse
row instead of 4 (Fig. 1E). This interrupted condi-
tion of transverse pronotal median setae occurs in
specimens of S. perseae from populations in Gua-
temala, California, and Mexico (Fig. 2B), making
it impossible to distinguish S. uruapaniensis as a
species distinct from S. perseae.
It is proposed here that S. aguacate, S. kupan-
dae, S. manihotifloris, S. tacambarensis, and S.
uruapaniensis be synonomized with S. perseae.
Scirtothrips perseae Nakahara
Scirtothrips perseae Nakahara, 1997: 189-192
Scirtothrips aguacatae Johansen and Mojica-
Guzman, 1998: 34-36 syn.n.


March 2008






Hoddle et al.: Synonomy of Five Scirtothrips Species from Mexico


Fig. 1. Pronotums of the holotypes:
(A) Scirtothrips aguacate,
(B) S. kupandae,
(C) S. manihotifloris,
(D) S. tacambarensis,
(E) S. uruapaniensis.
Specimens are uncleared and slide
mounted in Balsam.


Scirtothrips kupandae Johansen and Mojica-
Guzman, 1998: 47-48 syn.n.
Scirtothrips manihotifloris Johansen and
Mojica-Guzman, 1998: 55-56 syn.n.
Scirtothrips tacambarensis Johansen and
Mojica-Guzman, 1998: 62-63 syn.n.
Scirtothrips uruapaniensis Johansen and
Mojica-Guzman, 1998: 66 syn.n.

CONCLUSIONS
The lack of significant structural differences
between the 5 holotypes of Scirtothrips described
from Mexico that have been examined for this


study, apart from differences that are known to be
naturally variable within S. perseae, and the fact
that each of these Mexican species falls within the
known range of structural variation of S. perseae
as confirmed by DNA analyses, leads to the con-
clusion that these 5 species associated with avoca-
dos are all the same species, S. perseae. The for-
mal synonymies listed above must raise further
doubts concerning the biological reality of the
other "new species" of Scirtothrips described in
Johansen & Mojica-Guzman (1998), of which 18
were collected from Mangifera indica, a plant not
native to Mexico. However, there will be no pres-
sure to consider the validity of those species until







Florida Entomologist 91(1)


March 2008


Fig. 2. The head and pronotum of 4 NaOH cleared and balsam mounted Scirtothrips perseae females collected
from avocados in Uruapan Mexico with species identity confirmed by DNA analyses.


such time as the quarantine service of a potential
importing country for Mexican mangos raises
concerns over potential risks to biosecurity that
could be caused by such a large number of differ-
ent pest species of Scirtothrips contaminating
imports.


ACKNOWLEDGMENTS

Dr. Roberto M. Johansen kindly provided the holo-
types used for this study. We thank Christina Hoddle,
Roger Burkes, and Michael Lewis for assistance with
preparation of photomicrographs.







Hoddle et al.: Synonomy of Five Scirtothrips Species from Mexico


REFERENCES CITED

HODDLE, M. S., AND L. A. MOUND. 2003.The genus Scir-
tothrips in Australia (Insecta, Thysanoptera, Thrip-
idae). Zootaxa 268: 1-40.
HODDLE, M. S., S. NAKAHARA, AND P. A. PHILLIPS. 2002.
Foreign exploration for Scirtothrips perseae Naka-
hara (Thysanoptera: Thripidae) and associated nat-
ural enemies on avocado (Persea americana Miller.)
Biol. Control 24: 251-265.
HODDLE, M. S., K. M. BETTER, AND J. G. MORSE. 2003.
The economic impact of Scirtothrips perseae Naka-
hara (Thysanoptera: Thripidae) on California avo-
cado production. Crop Protection 22: 485-493.
JOHANSEN, R. M., AND A. MOJICA-GUZMAN. 1998. The
genus Scirtothrips Shull, 1909 (Thysanoptera:
Thripidae, Sericothripini) in Mexico. Folia Entomol.
Mex. 104: 23-108.
MOUND, L. A., AND R. MARULLO. 1996. The Thrips of
Central and South America: An Introduction (In-
secta: Thysanoptera). Associated Publishers,
Gainesville Florida, U.S.A.
MOUND, L. A., AND J. M. PALMER 1981. Identification,
distribution, and host-plants of the pest species of


Scirtothrips (Thysanoptera: Thripidae). Bull. Ento-
mol. Res. 71: 467-479.
MOUND, L. A., AND R. ZUR STRASSEN. 2001. The genus
Scirtothrips (Thysanoptera: Thripidae) in Mexico: a
critique of the review by Johansen & Mojica-
Guzman (1998). Folia Entomol. Mex. 40: 133-142.
NAKAHARA, S. 1997. Scirtothrips perseae (Thysan-
optera: Thripidae), a new species infesting avocado
in southern California. Insecta Mundi 11: 189-192.
RUGMAN-JONES, P. F., A. R. WEEKS, M. S. HODDLE, AND
R. STOUTHAMER. 2005. Isolation and characteriza-
tion of microsatellite loci in the avocado thrips Scir-
tothrips perseae (Thysanoptera: Thripidae).
Molecular Ecol. Notes 5: 644-646.
RUGMAN-JONES, P. F., M. S. HODDLE, L. A. MOUND, AND
R. STOUTHAMER 2006. Molecular identification key
for pest species of Scirtothrips (Thysanoptera:
Thripidae). J. Econ. Entomol. 99: 1813-1819.
RUGMAN-JONES, P. F., M. S. HODDLE, AND R.
STOUTHAMER 2007. Population genetics of Scirto-
thrips perseae: tracing the origin of a recently intro-
duced exotic pest of Californian avocado orchards,
using mitochondrial and microsatellite DNA mark-
ers. Ent. Exp. Appl. 124: 101-115.







Florida Entomologist 91(1)


March 2008


BIOLOGICAL CONTROL OF PIERIS RAPAE IN NEW ENGLAND:
HOST SUPPRESSION AND DISPLACEMENT OF COTESIA GLOMERATA
BY COTESIA RUBECULA (HYMENOPTERA: BRACONIDAE)

R. G. VAN DRIESCHE
PSIS/Division of Entomology, University of Massachusetts, Amherst, MA 01003, USA

ABSTRACT

A survey of the imported cabbageworm, Pieris rapae (Lepidoptera: Pieridae), in cole crops in
Massachusetts found that a Chinese strain of Cotesia rubecula (Hymenoptera: Braconidae),
released in 1988, has spread and become the dominant parasitoid of this pest in central and
western Massachusetts, with an average of 75% parasitism. The previously dominant para-
sitoid of this host, Cotesia glomerata (Hymenoptera: Braconidae), has been displaced and is
now present only at trace levels (<1% of total parasitism).

Key Words: Cotesia rubecula, Cotesia glomerata, Pieris rapae, parasitoid displacement, eval-
uation, biological control, cole crops

RESUME
Un sondeo del gusano importado de repollo, Pieris rapae (Lepidoptera: Pieridae) en cultivos
de cruciferos en el estado de Massachusetts mostr6 que la distribuci6n de la variedad china
de Cotesia rubecula (Hymenoptera: Braconidae), liberada en 1988, ha sido extendida y ha
llegado a ser el parasitoide mas dominant de esta plaga en la parte central y occidental del
Massachusetts, con un promedio de parasitismo del 75%. El parasitoide anteriormente mas
dominant de este hospedero, Cotesia glomerata (Hymenoptera: Braconidae), ha sido des-
plazado y ahora solo es present en niveles muy bajos (<1% del parasitismo total).


For biological control of the pest butterfly Pieris
rapae (L.) (Lepidoptera: Pieridae), a population of
the parasitoid Cotesia rubecula (Marshall) (Hy-
menoptera: Braconidae) collected near Beijing,
China, was released in Deerfield, MA, in 1988.
Here I report the outcome of this release at the re-
gional level of western and central Massachusetts.
This same parasitoid, sourced from other loca-
tions, has previously invaded or been released in
other parts of North America. In 1963 on Vancou-
ver Island in British Columbia, a self-introduced
population was detected (Wilkinson 1966), and
later found south to Oregon (Biever 1992). This
strain was released in Missouri, New Jersey,
South Carolina, and Ontario (near Ottawa) (Putt-
ler et al. 1970; Williamson 1971, 1972). It did not
establish in Missouri (Parker & Pinnell 1972), but
may have done so in Ontario (Corrigan 1982).
This strain was determined to have an improp-
erly timed diapause induction response for east-
ern North America (Nealis 1985). In the 1980s, a
collection of this parasitoid from Yugoslovia was
released in Missouri, Virginia, and Ontario. In
1988, it was recovered in Virginia, but did not per-
sist (McDonald & Kok 1991). In 1993, C. rubecula
was found to be the dominant parasitoid of P ra-
pae in farming areas near Montreal, Quebec
(Godin & Boivin 1998).
The population ofC. rubecula released in 1988
in Massachusetts was collected by David Reed of


the USDA in Shenyang, China (42 north lati-
tude, 123 east longitude). In total, 99 female and
49 male C. rubecula adults, reared in quarantine
from Chinese-collected hosts or cocoons, were
sent to Massachusetts where they were released
in field cages in a pesticide-free, 0.1-ha collard
plot in Deerfield, MA (42 n. 1.) in 1988. Earlier
work (1985 and 1986) at this location indicated
that prior to this release, C. rubecula was not
present and the dominant parasitoid was C. glom-
erata (Van Driesche 1988), which caused 68-81%
parasitism per generation in unsprayed collard
plots with high host densities (Van Driesche &
Bellows 1988). The Chinese strain of C. rubecula
was released in 17 locations in southern New
England and by 2002, it was widely distributed in
New England, with recoveries being made up to
northern Vermont (Van Driesche & Nunn 2002).
Studies in Massachusetts from 1988-1992
(Van Driesche & Nunn 2002) at various release
sites suggested that this population of C. rubec-
ula established readily and spread quickly. Lim-
ited evidence was also collected suggesting that
as C. rubecula increased in abundance at particu-
lar sites, densities of Cotesia glomerata (L.), a
previously introduced parasitoid attacking P. ra-
pae, decreased. By 1992, C. rubecula accounted
for about half of all Cotesia parasitism of P rapae
at the Deerfield site (Van Driesche & Nunn 2002).
This study also indicated that parasitism by C.







Van Driesche: Cotesia Parasitism of Pieris rapae


rubecula could reach high levels. However, work
in this time period was not able to determine if
substantial displacement of C. glomerata would
occur regionally, nor if C. rubecula would become
widespread and important over the whole land-
scape. Here I report a survey undertaken in 2007
to assess the outcome of this 1988 release at the
landscape level, for the region of central and
western Massachusetts. With the above men-
tioned objectives, in 2007 I visited farms produc-
ing cole crops in Massachusetts to evaluate (1)
the proportion of sites with C. rubecula, (2) the
level of parasitism of P. rapae by C. rubecula, and
(3) the fraction of P rapae parasitism due to
C. rubecula.

MATERIALS AND METHODS

I collected samples of P rapae from 20 farms or
garden plots in 13 towns in 4 counties from cen-
tral and western Massachusetts, principally in
the Connecticut River valley, where vegetable
farms are most common. Larvae were returned to
the laboratory and dissected. Most larvae col-
lected were 3 or 4th instars, with limited numbers
of 5th instars. Because sampling was conducted at
the end of the first host generation, 1t and 2nd in-
stars were scarce. Also included in samples were
any Cotesia cocoons or P. rapae pupae found on
plants while searching for larvae. In total, 415 in-
sects were examined (either live P. rapae larvae,
live P rapae pupae, or live cocoons of C. rubecula
or cocoon groups of C. glomerata).
Immature stages of C. rubecula could be
readily distinguished from those of C. glomerata
by several characteristics, including the presence
of mandibles in 1t instars (C. rubecula only), pres-
ence of an anal hook or vesicle (C. rubecula only),
and the number of larvae per host (1 for C. rubec-
ula and 10-60 for C. glomerata). Eggs also can be
determined to species, but no parasitoid eggs
were found in this survey because it occurred late
in the first parasitoid generation.
In the field, larvae were detected by turning
over leaves with feeding holes and also closely ex-
amining the young leaves in the center of the
plant (a preferred feeding site). Plants sampled
were collards, broccoli, and cabbage. Any farm
(conventional or organic) or garden plot located
was checked and included in the survey if P rapae
larvae were present.

RESULTS

Cotesia rubecula was found at all 20 locations
sampled, indicating that this species is now
present throughout the region. In addition to be-
ing present on larger farms, the parasitoid was
found in patches of cole crops as small as 2 dozen
plants, even plots located in forested areas not


near other agricultural fields. Parasitism levels
by C. rubecula averaged 75% parasitism (summed
over all 415 life stages collected), with 16 of 20
sites having more than 60% parasitism (Table 1).
Damage to plants by P rapae, while not quanti-
fied, was light because few larvae reached the 5th
instar, the stage responsible for most feeding,
with the sole exception of farm #19, in Grafton,
where the lowest level of C. rubecula parasitism
(9%) was found. At this site, 65% (15/23) of the
sample consisted of 5th instars and damage to
plants (feeding and frass) was readily observed.
In contrast at the other 19 sites, only 10% of life
stages collected were 5th instars (44/415, of which
6 were small 5th instars parasitized by C. rubec-
ula). By comparison, in New Zealand, introduc-
tion ofC. rubecula caused 48-97% parasitism and
reduced P rapae 5th instar density by 88-97% in
experimental plots (Cameron & Walker 2002).
At the 20 farms in the survey, C. glomerata-
once a common, reasonably abundant parasitoid
in Massachusetts (Van Driesche 1988)-was vir-
tually absent. Of 310 parasitized P. rapae larvae
found in samples, 308 were due to C. rubecula
alone, 1 was a case of multiparasitism of both C.
rubecula and C. glomerata, and 1 was due to an
unknown dipteran. Thus of 310 Cotesia attacks,
99.7% (309) were due to C. rubecula, indicating
that C. rubecula has displaced C. glomerata. In
comparison, in 1990-1992, at release sites in Mas-
sachusetts, C. rubecula accounted for only 49% of
all Cotesia parasitism and in 1992 in Quebec, an-
other strain of C. rubecula accounted for 63% of
all P rapae parasitism (Godin & Boivin 1998).

DISCUSSION

These results indicate that in Massachusetts
at the landscape (not study plot) level a C. rubec-
ula population of Chinese origin (1) has displaced
C. glomerata and become the dominate parasitoid
of P rapae and (2) is widespread and exerts a high
level of control of the target pest. The introduction
of C. rubecula from China has achieved in large
measure the goal of this classical biological con-
trol project by causing high levels of mortality of
young P. rapae larvae. Also, because C. glomerata
has had an undesirable effect on the native but-
terfly Pieris napi oleracea Harris in New England
(Benson et al. 2003; Van Driesche et al. 2004), the
disappearance of C. glomerata due to competition
with C. rubecula may over time allow this species
to recolonize areas from which it has disappeared
(Scudder 1889), given that C. rubecula has little
effect on this species in the field (see laboratory
and field host preference test data in Van
Driesche et al. 2003). Finally, the area surveyed
did not reach the boundaries of this parasitoid's
distribution in the region and surveys in adjacent
areas (NY, VT, CT, RI, NJ) are likely to find simi-
lar outcomes.







Florida Entomologist 91(1)


March 2008


TABLE 1. RATES OF PARASITISM BY COTESIA WASPS IN PIERIS RAPAE FROM VEGETABLE FARMS IN MASSACHUSETTS,
JUN, 2007.

No. hosts attacked by each parasitoid
Location: Date Farm % parasitism
Farm# Town (Co.') (Jun) type2 95% CI (n3) Cotesia rubecula Cotesia glomerata Other

1 Hadley (HS) 6 CF 81 13 (32) 32 0 0
2 Amherst (HS) 6 CG 20 35 (5) 1 0 0
3 Westhampton (HS) 6 G 27 26 (11) 3 0 0
4 Northampton (HS) 6 CG 84 13 (32) 26 1 1
5 Westhampton (HS) 6 OF 67 17 (30) 20 0 0
6 Whately (HS) 7 OF 73 16 (30) 22 0 0
7 Whately (HS) 7 OF 100 0 (3) 3 0 0
8 E. Deerfield (F) 7 OF 80 14 (31) 25 0 0
9 Montague (F) 7 OF 100 0 (4) 4 0 0
10 Hadley (HS) 11 OF 88 12 (27) 24 0 0
11 Hadley (HS) 11 OF 93 9 (31) 29 0 0
12 Sunderland (HS) 12 CF 67 19 (24) 16 0 0
13 Hadley (HS) 12 OF 63 18 (27) 17 0 0
14 Agawam (HD) 13 OF 92 11 (25) 22 0 0
15 Agawam (HD) 13 CF 90 11 (27) 26 0 0
16 Amherst (HS) 13 OF 28 33 (7) 2 0 0
17 Charlemonte (F) 14 OF 80 35 (5) 4 0 0
18 Lancaster (W) 18 CF 65 17 (29) 19 0 0
19 Grafton (W) 18 OF 9 12 (23) 2 0 0
20 Northbridge (W) 18 CF 100 0 (12) 12 0 0
Total 75 4 (415) 309 14 15

Counties: Hampshire (HS), Hamden (HD, Franklin (F), and Worcester (W).
,Type of farm: conventional vegetable farm (CF), organic vegetable farm (OF), community garden plots (CG), individual garden
(G).
'Samples consisted of Pieris rapae larvae of all instars, plus all Cotesia cocoons orPieris rapae pupae found on foliage. Intended
sample size was 25-30 per site, unless this number could not be obtained.
'This was an instance of multiparasitism by both C. rubecula and C. glomerata.
'This was 1 instance of parasitism by an unidentified dipteran.


ACKNOWLEDGMENTS

I thank the growers who allowed me to visit
their fields. This material is based upon work sup-
ported by the Cooperative State Research Exten-
sion, Education Service, U.S. Department of Agri-
culture and the Massachusetts Agricultural Ex-
periment Station, as publication MAS3414.

REFERENCES CITED

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ELKINTON. 2003. Introduced braconid parasitoids
and range reduction of a native butterfly in New En-
gland. Biol. Cont. 28: 197-213.
BIEVER, K. D. 1992. Distribution and occurrence of Co-
tesia rubecula (Hymenoptera: Braconidae), a para-
site ofArtogeia rapae in Washington and Oregon. J.
Econ. Entomol. 85: 739-742.
CAMERON, P. J., AND G. P. WALKER 2002. Field evalua-
tion of Cotesia rubecula (Hymenoptera: Braconidae),
an introduced parasitoid of Pieris rapae (Lepi-
doptera: Pieridae) in New Zealand. Environ. Ento-
mol. 1: 367-374.
CORRIGAN, J. E. 1982. Cotesia (Apanteles) rubecula [Hy-
menoptera: Braconidae] recovered in Ottawa, On-


tario ten years after its release. Proc. Entomol. Soc.
Ontario 113: 71.
GODIN, C., AND G. BOIVIN. 1998. Occurrence of Cotesia
rubecula (Hymenoptera: Braconidae) in Quebec, 30
years after its introduction in North America. Cana-
dian Entomol. 130: 733-734.
MCDONALD, R. C., AND L. T. KOK. 1992. Colonization
and hyperparasitism of Cotesia rubecula (Hymen.:
Braconidae), a newly introduced parasite of Pieris
rapae, in Virginia. Entomophaga 37: 223-228.
NEALIS, V. 1985. Diapause and the seasonal ecology of
the introduced parasite, Cotesia (Apanteles) rubec-
ula (Hymenoptera: Braconidae). Canadian Entomol.
117: 333-342.
PARKER, F. D., AND R. E. PINNELL. 1972. Further stud-
ies of the biological control of Pieris rapae using sup-
plemental host and parasite releases. Environ.
Entomol. 1: 150-157.
PUTTLER, B., F. D. PARKER, R. E. PINNELL, AND S. E.
THEWKE. 1970. Introduction of Apanteles rubecula
Marsh. and other parasites of Pieris rapae in British
Columbia. J. Econ. Entomol. 63: 304-305.
SCUDDER, S. H. 1889. The Butterflies of the Eastern
United States and Canada: Vol. 1. Pub. by author,
Cambridge, Massachusetts.
VAN DRIESCHE, R. G. 1988. Survivorship patterns of
Pieris rapae (Lep.: Pieridae) larvae in Massachu-







Van Driesche: Cotesia Parasitism of Pieris rapae


setts kale with special reference to mortality due to
Cotesia glomerata (Hymen.: Braconidae). Bull. Ent.
Res. 78: 199-208.
VAN DRIESCHE, R. G., AND T. S. BELLOWS. 1988. Host
and parasitoid recruitment for quantifying losses
from parasitism, with reference to Pieris rapae and
Cotesia glomerata. Ecol. Entomol. 13: 215-222.
VAN DRIESCHE, R. G., AND C. NUNN. 2002. Establish-
ment of a Chinese strain of Cotesia rubecula (Hy-
menoptera: Braconidae) in New England. Florida
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VAN DRIESCHE, R. G., C. NUNN, N. KREKE, B. GOLD-
STEIN, AND J. BENSON. 2003. Laboratory and field
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invasive Pieris butterflies. Biol. Cont. 28: 214-221.


VAN DRIESCHE, R. G., C. NUNN, AND A. PASQUALE. 2004.
Life history pattern, host plants, and habitat as de-
terminants of population survival of Pieris napi ole-
racea interacting with an introduced braconid
parasitoid. Biol. Cont. 29: 278-287.
WILKINSON, A. T. S. 1966. Apanteles rubecula Marsh.
and other parasites ofPieris rapae in British Colum-
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Parasites and Predators 1970. Agric. Canada Liber-
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Florida Entomologist 91(1)


March 2008


NEOMUSOTIMA FUSCOLINEALIS (LEPIDOPTERA: PRYALIDAE) IS AN
UNSUITABLE BIOLOGICAL CONTROL AGENT OF LYGODIUM JAPONICUM

CHRISTINE A. BENNETT1 AND ROBERT W. PEMBERTON2
'University of Florida, Institute of Food and Agriculture, Entomology Department,
1911 SW 34th St., Gainesville, FL 32608

2United State Department of Agriculture, Agriculture Research Service, Invasive Plant Research Laboratory,
3225 College Avenue, Ft. Lauderdale, FL 33314

ABSTRACT

In its native Japan Neomusotima fuscolinealis Yoshiyasu feeds on and damages the leaves
ofLygodium japonicum (Thunberg ex Murray) Swartz, an invasive weed in Florida and the
southeastern U.S. Larvae and pupae of the moth were imported into the quarantine facility
at the Florida Biological Control Laboratory, Gainesville, Florida, to establish a colony for
preliminary host range studies and to define its lifecycle and reproduction parameters. Lar-
vae of the moth did not feed significantly nor develop on 5 tested rare, native Florida ferns.
The rare North American native climbing fern, Lygodium palmatum (Bernhardi) Swartz,
however, supported complete development ofN. fuscolinealis, and 6 continuous generations
of the moth were reared on the fern. Because the rare L. palmatum and the invasive
L. japonicum co-occur in the US, the release of N fuscolinealis could result in the harm to
L. palmatum, a risk that makes the moth unsuitable as a potential biological control of
L. japonicum.

Key Words: Lygodium palmatum, Florida, rare native ferns

RESUME

Neomusotima fuscolinealis Yoshiyasu es una polilla indigena del Jap6n donde se alimenta y
dana las hojas de Lygodium japonicum (Thunberg ex Murray) Swartz, una maleza invasora
en la Florida y en el sureste de los Estados Unidos. Larvas y pupas de la polilla fueron im-
portadas a la facilidad de cuarentena en el Laboratorio de Control Biol6gico de Florida, Gai-
nesville, Florida, para establecer una colonia para realizar studios preliminaries del rango
de hospederos, definir el ciclo de vida y sus parametros de reproducci6n. Larvas de la polilla
no se alimentaron significativamente, ni se desarrollaron sobre los 5 helechos raros y nativos
de la Florida probados. Sin embargo, el helecho trepadora raro y native para norteamerica,
Lygodium palmatum (Bernhardi) Swartz, sostuvo el desarrollo complete de N. fuscolinealis
y 6 generaciones continues de dicha polilla fueron criadas sobre el helecho. Debido a que el
helecho raro, L. palmatum y L. japonicum (un helecho invasor) coexisten en los Estados Uni-
dos, la liberaci6n de N. fuscolinealis puede resultar en un dano a L. palmatum, un riesgo que
hace la polilla del Jap6n inapropiada como un candidate potential para el control biol6gico
de L. japonicum.


Lygodium japonicum (Thunberg ex Murray)
Swartz), Japanese climbing fern, is rapidly
spreading from northern Florida into central and
southern regions of the state. First introduced
into the United States as an ornamental around
1900, populations of Japanese climbing fern are
now present in nine states from the Carolinas
through Georgia, Florida, Alabama, Mississippi,
and Louisiana to Texas and Arkansas (Nauman
1993; Langeland & Burks 1998). In Florida, L.
japonicum has been reported in 53 of 67 counties
(Van Loren 2006).
Lygodium japonicum is a perennial fern with
wiry brown rachis and yellowish green leaflets or
pinnules capable of forming thick mats that can
shade and eliminate underlying vegetation. (Nau-
man 1993). Lygodiumjaponicum is similar in ap-


pearance to L. microphyllum (Canvanilles) R.
Brown, the other more invasive climbing fern
that is a problem in more moist habitats of south-
ern and central Florida. The margins of the sterile
leaflets of L. japonicum are toothed compared
with the entire margins ofL. microphyllum.
A decision was made to develop a biological
control project for the Old World climbing fern
(L.microphyllum) in 1997 (Pemberton et al. 2002),
but not for L. japonicum because the weed is par-
tially sympatric with the rare native congener
L. palmatum in its range in the eastern US. Our
concern was, and is, that biological control agents
developed for L. japonicum might harm the rare
L. palmatum. An opportunity to test that possibil-
ity arose when an herbivorous moth ofL. japoni-
cum was discovered in Japan.







Bennett & Pemberton: Moth Unsuitable Biological Control Agent


On Oct 3, 1997 R. W. Pemberton discovered lar-
vae of a pyralid moth, subsequently determined
to be Neomusotima fuscolinealis Yoshiyasu, feed-
ing on the fronds of L. japonicum plants in 3 areas
of the Tokyo Botanical Garden in Japan. The
young larvae fed gregariously, skeletonizing the
leaflets, and older larvae completely consumed
the blade tissue of the leaflets pinnaee). Pupae
were found within the webbing and frass associ-
ated with feeding larvae. Two infested L. japoni-
cum plants were growing in a shade and glass
house occupied by a diverse planting of fern spe-
cies. Searches of these other ferns failed to yield
either N. fuscolinealis larvae or the characteristic
damage, suggesting that the moth might have a
high degree of host specificity. On Oct 7, the lar-
vae were found feeding on L. japonicum vines in
the Honda section of Tsu City in Mie Prefecture
about 300 km west of Tokyo. The characteristic
damage by the moth was also found on L. japoni-
cum growing in Ugata-Yokoyama Park, s. of Ise in
Mie Prefecture. Larvae from Tokyo were fed
leaves of L. japonicum and reared to the pupal
stage. Specimens of reared adults were deter-
mined to be N. fuscolinealis by lepidopterist Yu-
taka Arita, of Meijo University, Nagoya, Japan.
The immature stages and host plant of this moth
were previously unknown (Y Arita, pers. comm.).
On a subsequent trip to Japan in Jun 2002, N.
fuscolinealis was sought in the Tokyo Botanical
Garden and the Mie locations but was not found.
In Sep 2002 larvae and pupae were collected in
the Tokyo Botanical Garden and shipped to the
U.S. for biological studies and preliminary host
range tests focusing on the native North Ameri-
can L. palmatum. Lygodium palmatum is a tem-
perate plant that ranges north to New York along
the Eastern seaboard, but is generally local and
rare except on the Cumberland Plateau of Ken-
tucky and Tennessee (Nauman 1973). Thus, the
weedy Lygodium and the rare Lygodium are sym-
patric in the upper South and the Carolinas. If
preliminary feeding tests in quarantine demon-
strated that L. palmatum could not support the
development of N. fuscolinealis, then additional
host range research would be conducted to more
precisely determine its potential host range in
North America.

MATERIALS AND METHODS

All research was conducted at the quarantine
facility at the Florida Biological Control Labora-
tory, Division of Plant Industry, Florida Depart-
ment of Agriculture and Consumer Services,
Gainesville, Florida, from Sep 2002 to May 2003.
Lygodium japonicum plants were collected in
Hamilton, Suwannee, and Madison counties,
Florida by Dr. Min Rayamajhi, USDA-ARS, IPRL,
Ft. Lauderdale, Florida, and L. palmatum plants
were collected in Rome Co., Tennessee, by the se-


nior author. A shipment of 40 N. fuscolinealis lar-
vae and pupae was received from Japan on Sep
30, 2002 collected by Tokyo Metropolitan Univer-
sity colleague Akira Shimizu and students at the
Tokyo Botanical Garden site.
First generation adults were transferred to a
screen sleeve cage (30.5 x 30.5 x 30.5 cm) contain-
ing a bouquet of cut sprigs of L. japonicum and
held in a quarantine laboratory at 22C. Adults
were fed 10% honey-Gatorade solution provided
on a rolled dental cotton wick in a 7-dram glass
vial filled with the solution. A bouquet of L. pal-
matum was added, and then bouquets of both
plants were changed every 3-4 d until the adults
died. Bouquets with eggs were removed from the
cage and separated by plant species into 28 x 15 x
5 cm translucent plastic rearing boxes. The boxes
were checked daily for egg hatch and larval devel-
opment, and fresh plant material was added
when necessary until adult emergence.
After establishment, the colony was held in the
greenhouse at an average temperature of 23C,
and natural light supplemented by fluorescent
lights with a photoperiod of 16:8 (L:D). Adults were
exposed to plants of both species together in
wooden sleeve cages 47.0 x 55.0 x 47.0 cm or 54.6 x
72.4 x 44.5 cm until the adults died. To conserve L.
palmatum plants, only 50 eggs on each of 3 plants
of each Lygodium species were allowed to hatch.
Larvae were allowed to feed freely on the plant of
their choice until pupation, and plants with pupae
were caged separately. New adults emerging from
each species were counted and sexed with aid of a
stereomicroscope and placed back in the sleeve
cages on fresh plants of both species.
As the experiment progressed and the supply
of L. palmatum plants dwindled, the number of
eggs allowed to develop on each plant had to be
further reduced to 25 per plant on 3 plants of each
Lygodium species.

Biological Studies

All studies were conducted in environmental
chambers at 26.7C, 75% RH, and a photoperiod
of 16:8 (L:D), unless otherwise indicated. Individ-
ual larvae on Japanese climbing fern were con-
fined in plastic boxes with lids, 8.0 x 8.0 x 5.0 cm.
The boxes were examined daily during the life-
time of the experiment for larval development,
pupation, and adult emergence.
Newly emerged adults were paired in plexi-
glass cylinders (42 cm high, 14.5 cm ID) with a
bouquet of L. japonicum sprigs to determine fe-
cundity and adult longevity. The bouquets were
changed daily, and eggs were counted and cut
from the leaflets. Eggs on the small pieces of leaf
material were then placed on moist cotton in 30-
ml clear plastic cups capped with a translucent
plastic lid with a cotton-plugged hole and checked
daily for eclosion.







Florida Entomologist 91(1)


To determine whether adults could survive cold
temperatures, 5 males and 5 females were placed
individually in 15-mL plastic vials with no paper
or plant material. The vials were then placed in a
household refrigerator freezer at -4C for 24 h.

Multi-choice Larval Host Range Studies

The plastic boxes used in the biological studies
were also used in a multi-choice host range exper-
iment with medium sized larvae. Approximately
900 mm2 (30 x 30 mm) of fronds from 5 native spe-
cies, 4 of which are listed as endangered by the
Florida Department of Agriculture (Nelson 2000),
were tested together. A companion control treat-
ment had an equal amount ofL. japonicum, 4500
mm2. Each test had 5 replications of each treat-
ment each with 3 larvae randomized to treat-
ments in groups of 3. The replicates were random-
ized to positions on a laboratory table. After 3 d,
the number of living larvae was recorded and
feeding on the test plants was estimated with a 1-
mm2 grid. Feeding on host plants was estimated
by counting the number of leaves and multiplying
by an estimated mean leaf area. The estimated
mean area was determined by measuring L.
japonicum leaflets with a Li-Cor Portable Leaf
Area Meter, model Ll-3000. Fifteen samples of
leaflets, each approximately 900 mm2, were mea-
sured and a mean leaf area was determined.
One host range experiment was conducted in
the small screen sleeve cage in a quarantine green-
house. Bouquets ofL. microphyllum were exposed
to N. fuscolinealis adults for 4 d. Plant material
with eggs was then placed in the plastic translu-
cent rearing boxes and held for adult emergence.

RESULTS AND DISCUSSION

Results of the rearing experiments are summa-
rized in Table 1. Fourteen females and 2 males
emerged from the pupae sent from Japan. These


insects were exposed to bouquets of L. japonicum
andL. palmatum and initially all the eggs but one
were deposited on Japanese climbing fern. One
hundred and forty females and 105 males
emerged from L.japonicum compared to no adults
from the L. palmatum. These adults were then
divided into 2 cages with bouquets of both plant
species. Adults were produced on both species of
plants. The experiment continued for 6 genera-
tions, with the result that adults produced on
L.japonicum were 1,202 females and 979 males
compared to 249 females and 230 males produced
on L. palmatum. It was concluded after the 6th
generation that L. palmatum could support com-
plete development of N. fuscolinealis and the in-
sect was not specific enough to be considered as a
biological control agent of Japanese climbing fern.

Biological Studies

The moths mate shortly after emergence, usu-
ally at night. Females lay the eggs on both sides of
the leaflets usually the second night after emer-
gence. The eggs initially are flat, but swell as they
mature and the developing larva is visible through
the chorion prior to egg hatch. The duration of the
egg stage averages 9 d. Larvae are yellowish-
cream to green in color with black spots and dark
brown heads. The young larvae feed by scraping
the surface of the new growth, while older larvae
eat the entire leaflet including older and fertile
leaves. The duration of the larval stage is 11.2
1.1 d (n = 21). The mature larva spins a very loose
web of silk on the leaflet and rachis and forms a
brown naked pupa beneath it. The development
time for the pupal stage is 5.7 + 0.6 d (n = 21).
The adults are brown with distinctive white
boomerang-shaped marks near the margin of the
forewing. The development time from neonate to
adult at 26.7C is 16.9 1.3 d (n = 21). None of the
individual insects were followed from egg deposi-
tion to adult, so the total developmental time was


TABLE 1. NEOMUSOTIMA FUSCOLINEALIS ADULTS PRODUCED ON TWO LYGODIUMS.

Lygodium japonicum Lygodium palmatum

Generation Females Males Females Males

Parents 14 2 0 0
Fl 140 105 0 0
F2 171 208 113 118
F3 136 96 79 55
F4 278 179 37 37
F5 259 230 13 16
F6 264 159 7 4
Total 1262 979 249 230
Means 180 140 36 33
SD 95 78 44 43


March 2008







Bennett & Pemberton: Moth Unsuitable Biological Control Agent


TABLE 2. MULTI-CHOICE TEST OF NEOMUSOTIMA FUSCOLINEALIS LARVAE WITH RARE NATIVE FERNS.'

Living larvae Ferns eaten (mm2)

Plant species Mean SE Mean SE

Actinostachys pennula 1.2 0.3 0.0 0.0
Anemia adiantifolia 1.2 0.3 0.4 0.2
Ctenitis sloanei 1.2 0.3 0.0 0.0
Tectaria fimbriata 1.2 0.3 4.6 2.7
Tectaria heracleifolia 1.2 0.3 25.4 9.0
Lygodiumjaponicum 2.2 0.1 224.9 53.3

'First 5 species tested together in same cage with 900 mm2 of cut fronds of each species except A. pennula, which had 100 mm2.
An equal amount of L. japonicum, 4,500 mm2, was in each control cage. There were 3 medium-sized larvae in each cage for 3 d and
5 replications each of the treatment and control.


estimated. Total developmental time at 26.7C
should be 24-30 d based upon an egg stage of 9 d
and the larval/adult times.
In oviposition studies, females laid an average
of 146.6 84.0 (2-233) eggs and 68.8 24.3% of
the eggs hatched. Female longevity averaged 6.9
+ 2.6 d (n = 12) compared with the male at 11.1 +
2.2 d (n = 9).
One female survived 24 h at -4C without plant
material or moisture. After removal from the
freezer, the female survived 2 more d in a cage in
the greenhouse.

Multi-choice Tests

The results of the multi-choice test with a com-
panion control are presented in Table 2. There
was no feeding onActinostachys pennula (Swartz)
Hooker and Ctenitis sloanei (Poeppig ex Sprengel)
C.V. Morton. Feeding on Anemia adiantifolia
(Linnaeus) Swartz was minimal, averaging 0.4
mm2. The 2 species of Tectaria were both attacked,
but T heracleifolia (Willdenow) L. Underwood
suffered heavier damage than the related T fim-
briata (Willdenow) Proctor & Lourteig. However,
the feeding on both species of Tectaria was slight
when compared with the feeding on the control.
Females oviposited on bouquets of L. micro-
phyllum in a sleeve cage in the greenhouse. Sixty
six adults were produced in the first generation
and 77 adults in the second generation.
Neomusotima fuscolinealis was eliminated as
a potential biological control agent of L. japoni-
cum because of its potential use of the rare native
L. palmatum. Our studies demonstrated that the
moth could complete its development on the plant
for multiple generations.


ACKNOWLEDGMENTS

The authors thank Yutaka Arita for identifying N.
fuscolinealis and Akira Shimizu for collecting and ship-
ping larvae and pupae to Florida, Gary Buckingham for
help with experimental design and other technical ad-
vice, Min Rayamajhi for supplying Lygodium japoni
cum, and Luke Kasarjian for providing the other plants
used in the study. We thank William Bennett for finding
Lygodium palmatum and allowing us to collect the
plants. This research was supported by the Florida De-
partment of Environmental Protection.


REFERENCES CITED

LANGELAND, K., AND A. K. CRADDOCK BURKS (eds.).
1998. Lygodium japonicum (Thunb.) SW, pp. 14-15 In
Identification & Biology of Non Native Plants in Flor-
ida's Natural Areas. University of Florida. 165 pp.
NAUMAN, C. E. 1993. Lygodiaceae C. Presl. pp. 114-116
In Flora of North America, Editorial Committee
[ed.]. Flora of North America North of Mexico. Vol. 2.
Oxford University Press, NY.
NELSON, G. 2000. The Ferns of Florida. A Reference and
Field Guide. Pineapple Press, Sarasota, FL. 208 pp.
PEMBERTON, R. W., J. A. GOOLSBY, AND T. WRIGHT.
2002. Old World climbing fern, pp. 139-147 In R. Van
Driesche, B. Blossey, M. Hoddle, S. Lyon, and R.
Reardon [eds.], Biological Control of Invasive Plants
in the Eastern United States. Forest Health Tech-
nology Enterprise Team-FHTLET-2002-04, Mor-
gantown, WV. 413 pp.
SOLIS, M. A., S.-H. YEN, AND J. A. GOOLSBY. 2004. Spe-
cies o01 il ..-..--.. .,New Genus and Neomusotima
Yoshiyasu (Lepidoptera: Crambidae) from Australia
and Southeastern Asia Feeding on Lygodium micro-
phyllum (Schizaeaceae). Ann. Entomol. Soc. Amer-
ica. 97: 64-76.
VAN LOAN, A. N. 2006. Japanese climbing fern: The in-
sidious "other" Lygodium. Wildland Weeds 9: 25-27.







Florida Entomologist 91(1)


A NEW PARELBELLA FROM MEXICO
(HESPERIIDAE: PYRGINAE: PYRRHOPYGINI)

OLAF H. H. MIELKE1, GEORGE T. AUSTIN2 AND ANDREW D. WARREN2'3
'Departamento de Zoologia, Universidade Federal do Parana, Caixa Postal 19020,
81531-980 Curitiba, Parana, Brazil

2McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History,
University of Florida, P.O. Box 112710, Gainesville, FL 32611

3Museo de Zoologia, Facultad de Ciencias, Departamento de Biologia Evolutiva,
Universidad Nacional Aut6noma de M6xico, Apdo. Postal 70-399, M6xico, D.F. 04510, M6xico

ABSTRACT
A new species of Parelbella is named and described. It is known from the states of Veracruz
and Oaxaca, M6xico, and may be endemic to the southern Sierra Madre Oriental.

Key Words: Hesperiidae, Mexico, Parelbella, Pyrginae

RESUME

Se describe una especie nueva de Parelbella. Se conoce de los estados de Veracruz y Oaxaca,
M6xico, y posiblemente es end6mico a la parte austral de la Sierra Madre Oriental.


Translation provided by the authors.


Parelbella (Hesperiidae: Pyrginae: Pyrrhopy-
gini) was proposed by Mielke (1995) for a group of
4 Neotropical species occurring from northern Ar-
gentina and eastern Paraguay northward into
southern Mexico. A single species, Parelbella ma-
cleannani (Godman & Salvin, 1893), has been
known from the northern extreme of this distribu-
tion, ranging southward into northern South
America. An undescribed species potentially sym-
patric with P macleannani, discovered in the col-
lection of Allyn Museum of Entomology, now
housed at the McGuire Center for Lepidoptera
and Biodiversity, is described herein.

Parelbella nigra Mielke, Austin & A. Warren, sp. n.
(Figs. 1A, B, a, b; 2A, C)

Description. Male-FW length = 25.6 mm (ho-
lotype), 25.0 mm (paratype). Forewing pointed
apically, termen nearly straight, anal margin
slightly concave just basad of middle; black; 3
aligned opaque white macules angled from mid-
costa toward just basad of tornus, broadest mac-
ule in discal cell, rectangular, extending distad
just beyond origin of CuA,; narrower macule in
CuA,-CuA,, hourglass-shaped, entirely basad of
origin of CuA1, outlined distad with single row of
pale blue scales; still narrower and pointed
caudad macule in anterior half of CuA2-2A, out-
lined distad and posterior half proximad with sin-
gle row of pale blue scales; small pale blue macule
at base of discal cell; pale blue postbasal band


across wing from anal margin to anterior discal
cell continued in costal cell by a few pale blue
scales; a few pale blue scales just caudud of CuA2
about one-third distance from base to termen;
narrowly triangular pale blue macule extending
along vein 2A from about mid-CuA2-2A to beyond
end of white macule; another parallel pale blue
macule in anal cell extending distad of that in
CuA,-2A to submargin; irregular and less distinct
submarginal patches of pale blue scales in M3-
CuA1, CuA,-CuAk, and CuA,-2A; a few pale blue
submarginal scales in mid-M,-M,; fringe black
with a few pale scales in CuAk-2A.
Hindwing termen slightly undulate to a short
projection at end of vein 2A; mostly black, but
browner along costa and with gray-brown scaling
along anal margin; pale blue submarginal band di-
vided by black veins, narrowing somewhat from Rs
to 2A, curving slightly caudad; similar, more or less
parallel medial band, about equally broad through-
out, anteriormost and posteriormost portion with
scales like those of submarginal band, mid-portion
(between veins M1 and CuA2) of bluish white hair-
like scales; vague pale blue macule in Sc+R,-Rs be-
tween submarginal and medial bands; postbasal
curved band of bluish white hair-like scales from
anterior discal cell to beyond 2A; fringe white with
black at tips of veins, a few black scales intermixed
between veins, mostly black posterior to vein 2A.
Ventral forewing duller than dorsum, distinctly
brown caudad of CuAk; white macules of dorsum
repeated with additional narrow white macules in


March 2008







Mielke et al.: New Mexican Parelbella


Fig. 1. Parelbella from Mexico: A (dorsal), a (ventral)-Parelbella nigra holotype male, MEXICO: Oaxaca; Toton-
tepec, Jul 1950; B (dorsal), b (ventral)-Parelbella nigra allotype female, MEXICO: Oaxaca; Totontepec, Jul 1950;
C (dorsal), c (ventral)-Parelbella macleannani female, MEXICO: Oaxaca; Rio Sarbia, Aug 1958; D (dorsal), d (ven-
tral)-Parelbella macleannani, female, MEXICO: Oaxaca; Chimalapa, Sep 1956.







Florida Entomologist 91(1)


R,-R2 extending just distad of distal end of macule
in discal cell and in Sc-R, from mid-macule in R,-
R2 to well distad of distal end of that macule
roughly aligned with white macule in discal cell;
pale blue macule at base of costa; postbasal band
faint, most prominent in discal cell; thin line of
pale blue scales at distal end of discal cell; sub-
marginal pale blue macules somewhat more
prominent than on dorsum, that in CuA2-2A dou-
bled; pale blue macule in anal cell as on dorsum.
Ventral hindwing duller black than on dorsum;
submarginal pale blue band similar to that on
dorsum paralleled distad by much narrower pale
blue line from Rs to just caudad of M3, more or less
joined cephalad by rectangular pale blue macule
in Sc+R,-Rs; another similar but broader macule
in Sc+R,-Rs just proximad of submarginal band
with a narrow blue line overlapping both in costal
cell; medial band less well-defined than on dor-
sum consisting of individual and well-separated
macules; postbasal band also vague, most promi-
nent cephalad.
Head black, dorsum with narrow transverse
lines, white medio-caudad of palpi, white between
antennae, white dorsad of mid-eyes, pale blue be-
hind antennae, broader white to pale blue ceph-
alad on collar extending behind eyes and very
broadly beneath eyes onto ventro-lateral portion
of palpi, caudal portion of collar black; eyes dark
gray; palpi black dorsad, third segment black,
short, stout, porrect; antennae black with sparse
whitish scales ventrad on club, apiculus dull red-
brown of 20 holotypee) and 21 (paratype) seg-
ments. Thorax black, dorsum with narrow trans-
verse pale blue line cephalad, dorso-lateral pale
blue lines on tegulae narrowing caudad (central
portion of dorsal and lateral thorax rubbed, may
have pair of narrow central blue lines as does fe-
male and other congeners), venter with pair of
medial white lines narrowing caudad, legs black
with narrow white laterally, broadest on femur.
Abdomen slightly greased (may have been
brighter), black dorsally and laterally with nar-
row pale blue transverse lines at segments later-
ally (leaving broad black dorsal ridge), these nar-
rowing ventrad and caudad; ventral abdomen
dark gray with transverse white to pale blue at
segments narrowing posteriorly; terminal tuft
dark gray, highlighted with pale ochre scales
caudad from distal end of segment 7 to distal tip.
Genitalia (Fig. 2A). Uncus undivided, robust,
strongly decurved with hook at caudal end; tegu-
men hood-like with pair of lateral processes from
caudal end slightly divergent, slightly decurved,
toothed along central edge; vincular arc [we use
this descriptive term for the combined and often
curved ventral appendix of the tegumen and dor-
sal appendix of the saccus (e.g., see Pierce 1914)
termed the vinculum by many authors (see also
Torre-Bueno 1937)] thin, slightly sinuate; saccus
long, thin, oriented nearly vertically; valva with


costa-ampulla broadly humped narrowing caudad
to harpe, harpe with prominent more-or-less tri-
angular dorsal process strongly toothed on ceph-
alad edge, less so on caudal edge, this process ex-
ceeded by caudal lobe shorter than dorsal lobe,
prominently toothed on dorsal edge; aedeagus ro-
bust, about three-quarters length of valva, proxi-
mal part of aedeagus slightly curved ventrad.
Female-FW length = 29.6 mm (allotype),
29.1, 30.1 mm (paratypes). Forewing broader
than on male, pointed apically but more rounded
than on male, termen slightly curved, anal mar-
gin nearly straight, black; 3 aligned translucent
macules lightly scaled with white angled from
mid-costa toward just basad of tornus, broadest
macule in discal cell, trapezoidal (narrowest ceph-
alad) extending distad just beyond origin of CuAk;
narrower macule (nearly of equal width on
paratype) in CuA,-CuA,, hourglass-shaped, en-
tirely basad of origin of CuA, (extending slightly
distad on paratype), outlined distad with single
row of pale blue scales; still narrower and pointed
caudad macule in anterior half of CuAk-2A out-
lined distad with single row of pale blue scales;
cells Sc-R, and R1-R2 with narrow pale blue lines
cephalad of white band; small pale blue macule at
base of discal cell; pale blue postbasal band across
wing from anal margin to anterior discal cell
(vague on paratype); narrowly triangular pale
blue macule extending along vein 2A from about
mid-CuA,-2A to beyond end of white macule; an-
other parallel pale blue macule in anal cell ex-
tending distad of that in CuA2-2A to submargin;
irregular and less distinct submarginal patches of
pale blue scales in M3-CuA1, CuAI-CuAk, and
CuA2-2A; a few pale blue submarginal scales in
mid-M2-M3; fringe black.
Hindwing more convex and broader than on
male, termen slightly undulate to a short projec-
tion at end of vein 2A; mostly black, but slightly
browner along costa and anal margin; pale blue
submarginal band divided by black veins, narrow-
ing somewhat from Rs to 2A, curving slightly
caudad, broader pale blue macule posterior to vein
2A; similar, more-or-less parallel medial band,
about equally broad throughout, anteriormost
portion of scales like those of submarginal band,
posterior portion not well-defined, of blue scales
and bluish white hair-like scales; postbasal curved
band of bluish white hair-like scales from anterior
discal cell to beyond 2A; fringe white with black at
tips of veins, a few black scales intermixed in cell
Sc+R,-Rs, mostly black posterior to vein 2A.
Ventral forewing duller than dorsum, dis-
tinctly brown caudad of CuA,; white macules of
dorsum repeated, additional narrow blue-white
macules in R1-R2 extending just distad of distal
end of macule in discal cell and in Sc-R, extending
well distad of distal end of that macule; pale blue
macule at base of costa; postbasal band faint,
most prominent in discal cell (especially on


March 2008






Mielke et al.: New Mexican Parelbella


d


bIzz


Figure 2A


0a C




rz~ dd
b==:


Figure 2B


Figure 2C


Figure 2D


Fig. 2. Genitalia of Parelbella from Mexico. A. Parelbella nigra holotype, GTA #13765, data as in Fig. 1: (a) lat-
eral view of tegumen, uncus, saccus, and valva; (b) lateral (above) and dorsal (below) views of aedeagus; (c) dorsal
view of tegumen and uncus; (d) ventral view of saccus; B. Parelbella macleannani male, GTA #13767, MEXICO:
Oaxaca; Chimalapa, Jul 1953 (same views as 2A); C. Parelbella nigra allotype, GTA #13768, data as in Fig. 1 (lat-
eral view of caudal structures); D. Parelbella macleannani female, GTA #13766, MEXICO: Oaxaca; Rio Sarbia, Aug
1958 (same view as 2C).


paratype); thin line of pale blue scales at distal
end of discal cell; submarginal pale blue macules
similar to those on dorsum, that in CuA,-2A dou-
bled (not on paratype); pale blue macule in anal
cell as on dorsum.
Ventral hindwing duller black than on dorsum;
submarginal pale blue band similar to that on
dorsum paralleled distad by much narrower pale
blue line from Rs to CuA, vague rectangular pale
blue macule in Sc+R,-Rs between the two; similar
macule (more prominent on paratype) in Sc+R,-Rs
just proximad of submarginal band with a vague
narrow blue line overlapping both in costal cell;
medial band less well-defined than on dorsum,
prominent only in CuA2-2A and only a few pale


blue scales cephalad (better defined on paratype);
postbasal band vague throughout (better defined
on paratype).
Head same as male, but all lines pale blue
except that behind and beneath eye remaining
white, antennal nudum with 20, 21, and 22 seg-
ments. Thorax same as male, but dorsal markings
deeper blue (perhaps an artifact of greasing of
male's abdomen), pair of medial longitudinal pale
blue lines in addition to the broader ones more
laterally. Abdomen same as male, except segmen-
tal lines on venter pale blue.
Genitalia (Fig. 2C). Sterigma in lateral view
with curved caudal edge extended to prominent
point caudad from dorsal edge, cephalad edge bul-


a C







Florida Entomologist 91(1)


bous, papillae anales robust, more-or-less quad-
rate but being somewhat broader ventrally, cau-
dal edge straight.
Types. Holotype male with the following la-
bels: white with black lines enclosing data,
printed and handwritten / T. Escalante / Toton-
tepec / Oax / vii-50 /; white printed /A. C. Allyn /
Acc. 1973-48 /; white, printed / MGCL/FLMNH /
Specimen no. / 40755 /; white, printed and hand-
written / Genitalic Vial / GTA-13765 /; red,
printed / HOLOTYPE IParelbella nigra / Mielke,
Austin & A. Warren /. Allotype female with the
following labels: white with black lines enclosing
data, printed and handwritten / T. Escalante /
Totontepec / Oax. / vii-50 /; white printed / A. C.
Allyn / Acc. 1973-48 /; white, printed / MGCL/
FLMNH / Specimen no. / 40756 / white, printed
and handwritten / Genitalic Vial / GTA-13768 /;
red, printed / ALLOTYPE / Parelbella nigra /
Mielke, Austin & A. Warren /. Paratype female
with the following labels: white with black lines
enclosing data, printed and handwritten / T Es-
calante / Presidio / Ver / vii-54 /; white printed /
A. C. Allyn / Acc. 1973-48 /; white, printed /
MGCL/FLMNH / Specimen no. / 40757 /; blue,
printed / PARATYPE /Parelbella nigra / Mielke,
Austin & A. Warren /. The types above are depos-
ited at the McGuire Center for Lepidoptera and
Biodiversity, Florida Museum of Natural History,
University of Florida, Gainesville, Florida. Two
additional paratypes, at the Instituto de Biologia,
UNAM (IBUNAM), Mexico City, are from MEX-
ICO: Oaxaca, Puerto Eligio, V-1978, Adolfo Ibarra
(male) and MEXICO: Oaxaca; Chiltepec, VIII-68,
Diaz Frances (female). The primary types and ex-
amples of P macleannani from Mexico are illus-
trated in color on the McGuire Center's website <
http://www.flmnh.ufl.edu/mcguire/ >.
Type Locality. MEXICO: Oaxaca; Municipio
Totontepec Villa de Morelos, Totontepec. The holo-
type and allotype of P nigra are labeled as from
Totontepec, Oaxaca, situated at about 2000 m in
the southeastern part of the Sierra de Juarez
(Sierra Mixe). Native habitats at this elevation
should include moist montane cloud forest. Chil-
tepec (Mpio. San Jose Chiltepec) and Puerto Eligio
(Mpio. Santiago Comaltepec) also are situated in
the Sierra de Juarez at 100 and 650 m, respec-
tively). The fauna of Papilionoidea of this region
has recently been studied (e.g., Luis et al. 1991)
and several taxa are known to be endemic to the
region (e.g., Papilio esperanza Beutelspacher,
1975, Papilionidae; Paramacera chinanteca L. D.
Miller, 1972, Nymphalidae). A female paratype of
P nigra is labeled as from Presidio, Veracruz. Pre-
sidio was a ranch near Totutla (Mpio. Totutla) fre-
quented by various Mexican naturalists, from
which collections were made at nearby localities
including Orizaba, C6rdoba and Fortin de las
Flores, on the eastern slope of the Sierra Madre
Oriental at approximately 1000-2500 m. The


ranch is now apparently known as Finca Hilde El
Mirador (J. Brock, pers. comm. 2007). In general,
habitats in this region have been altered drasti-
cally since the specimen ofP. nigra was collected in
1954, but included moist montane cloud forest and
semi-deciduous tropical forest at lower elevations.
Etymology. The species is named after its very
dark aspect due to the absence of white macules
in the apical portion of the forewing as occur on
other species of the genus.

DIAGNOSIS AND DISCUSSION

Parelbella nigra is immediately distinguished
from its most similar congener, P. macleannani
(Fig. 1), by the absence of white subapical macules
on its forewing. In addition, P. macleannani usu-
ally has 1 or 2 white submarginal macules in M1-
M2 and/or M2-M3 that are also absent on P nigra.
Additional characters of the wings, color, and pat-
tern are abundantly different between the 2 taxa.
The male of P nigra has a triangular forewing that
is less truncated apically than on P. macleannani
and the hindwing is proportionally longer. Female
forewings of P nigra are more rounded than those
of P. macleannani and the hindwings are less
rounded. The white macules of the medial band on
the forewing are aligned or even slightly curved
distad on P nigra, while these tend to be curved in-
ward on P. macleannani. The blue on P nigra is
less intense than that of P macleannani on which
it is more extensive, with the submarginal macules
even extending to the subapex on the forewing. The
submarginal band on the hindwing of P nigra is
curved caudad on the male and curved throughout
on females, whereas these are much straighter on
P. macleannani. On the ventral hindwing, the blue
markings are again less extensive on P nigra on
which the medial and postbasal bands are poorly
developed and lack elements present on P ma-
cleannani. Finally, the terminal scales on the ab-
domen of P nigra are pale ochre in contrast to
whitish on P. macleannani.
Genitalia of P nigra have the overall gestalt
for the genus (Mielke 1995). The uncus appears
more robust than on other congeners. The pro-
cesses of the tegumen are likewise more robust
and exhibit both a distinctly toothed ventral edge
and a divergent aspect not seen on other Parel-
bella. The harpe has the caudal lobe shorter than
the dorsal process as noted for Parelbella po-
lyzona (Latreille [1824]) and Parelbella peruana
Mielke, 1995 (Mielke 1995). The dorsal process is
prominently toothed on its cephalad edge as also
illustrated for those two taxa (Mielke 1995). The
aedeagus appears more robust than those of other
Parelbella. The pointed dorsal edge of the female's
sterigma of P nigra is not seen on other Parelbella
on which this is blunt and has a dorsad orienta-
tion. Quadrate papillae anales were illustrated
only for P. macleannani (Mielke 1995).


March 2008







Mielke et al.: New Mexican Parelbella


In comparison with the sympatric P maclean-
nani, the genitalia of both sexes of P nigra are
distinctly different as illustrated (Fig. 2). It
should be noted that the genitalia of putative P.
macleannani from Mexico (Fig. 2B, D) differ in
several respects from those illustrated for the spe-
cies by Mielke (1995). It may be that P maclean-
nani as now constituted includes more than 1 spe-
cies. This is further reinforced by the differences
in markings between the specimens illustrated
here and those illustrated by Mielke (1995) from
Panama and Ecuador.
While P macleannani and P. nigra have not
been recorded at the same localities, they are po-
tentially sympatric with both occurring in the
states of Veracruz and Oaxaca in southern Mex-
ico. The available specimens suggest that P nigra
might be endemic to Mexico, particularly to the
southern Sierra Madre Oriental (which includes
the Sierra de Juarez) of Veracruz and Oaxaca, in
extremely humid regions. A specimen seen by Bell
(1942) in the Academy of Natural Sciences in
Philadelphia and described as having the subapi-
cal macules absent and a narrower blue pattern
may well have been P nigra and merits re-exam-
ination. In Mexico, Parelbella macleannani is
known from Dos Amates and Catemaco in Ver-
acruz, and San Miguel (Chimalapa) and Rio Sar-
bia in Oaxaca (Mielke 1995, this study). It also
has been reported at Sayaxche, El Peten, Guate-
mala, and then southward from Nicaragua to Co-
lombia and Ecuador (Mielke 1995; Burns & Jan-
zen 2001).


ACKNOWLEDGMENTS

We thank Andrei Sourakov for assembling Fig. 1 and
Christine Eliazar for preparing Fig. 2. Lee D. Miller,
Jacqueline Y. Miller, and Jorge Llorente reviewed ver-
sions of the manuscript and made valuable suggestions.
We also thank Jim P. Brock for information and Adolf
Ibarra for facilitating access to the IBUNAM collection.
Funding for A. D. Warren during completion of this
study was provided by DGAPA-UNAM.

REFERENCES CITED

BELL, E. L. 1942. New records and new species of Hes-
periidae from Mexico (Lepidoptera: Hesperiidae).
An. Esc. Nac. Cienc. Biol. 2: 455-468.
BURNS, J. M., AND D. H. JANZEN. 2001. Biodiversity of
pyrrhopygine skipper butterflies (Hesperiidae) in
the Area de Conservaci6n Guanacaste, Costa Rica. J.
Lepid. Soc. 55: 15-43.
LUIS, A. M., I. F. VARGAS, AND J. E. LLORENTE. 1991.
Lepidopterofauna de Oaxaca I: Distribuci6n y fenologia
de los Papilionoidea de la Sierra de Juarez. Publica-
ciones Especiales del Museo de Zoologia 3: iii, 1-119.
MIELKE, O. H. H. 1995. Revisao de Elbella Evans e
g6neros afins (Lepidoptera, Hesperiidae, Pyrrhopy-
ginae). Revta Brasileira Zool. 11: 395-586.
PIERCE, F. N. 1914. The Genitalia of the Group
Geometridae of the Lepidoptera of the British Is-
lands. An Account of the Morphology of the Male
Clasping Organs and the Corresponding Organs of
the Female. Publ. by author, Liverpool. 226 pp.
TORRE-BUENO, J. R. DE LA. 1937. A Glossary of Ento-
mology. Smith's "An Explanation of Terms Used in
Entomology", completely revised and rewritten. Sci-
ence Press, Lancaster, PA. 336 pp.







Florida Entomologist 91(1)


March 2008


CITRUS FLUSHING PATTERNS, DIAPHORINA CITRI (HEMIPTERA:
PSYLLIDAE) POPULATIONS AND PARASITISM BY TAMARIXIA RADIATA
(HYMENOPTERA: EULOPHIDAE) IN PUERTO RICO

RICHARD W. H. PLUKE, JAWWAD A. QURESHI AND PHILIP A. STANSLY
Department of Entomology and Nematology, University of Florida/IFAS
Southwest Florida Research and Education Center, 2686 SR 29N, Immokalee, FL 34142, USA

ABSTRACT

Discovery of citrus greening disease or Huanglongbing in Brazil and Florida has elevated
the vector psyllid, Diaphorina citri (Hemiptera: Psyllidae), to key pest status in both re-
gions. Detected in Puerto Rico within 3 years of first detection in Florida, the psyllid ap-
peared to be relatively scarce in the Island's limited citrus and alternate rutaceous host,
orange jasmine, Murraya paniculata. Monthly surveys were conducted at 4 locations during
2004 through 2005 to evaluate citrus flushing patterns, psyllid densities, and prevalence of
parasitism by Tamarixia radiata. Although low levels of D. citri are known to be established
in the high, cool areas ofAdjuntas, a total lack of psyllids at the particular study location was
attributed to scarcity of flush except for a short period in Feb. Greatest and most prolonged
production of new flush, highest psyllid numbers, and greatest incidence of parasitism oc-
curred at Isabela, the most coastal location and the only one with irrigated citrus. Favorable
climate and irrigation resulted in prolonged availability of new foliage needed to maintain
populations of psyllids and consequently its parasitoid. There, apparent parasitism of late
instars was estimated to average 70% and approached 100% on 3 different occasions. Tam-
arixia radiata also was found parasitizing psyllid nymphs in orange jasmine at the rate of
48% and 77% at Rio Piedras and San Juan, respectively, approaching 100% on 5 occasions
during spring and summer. The corresponding decline in infestation during peak flush in
spring and later in the year could indicate that T radiata made important contributions to
the regulation of D. citri populations at these locations. Better understanding of factors fa-
voring high parasitism rates in Puerto Rico could lead to more effective biological control of
D. citri in other citrus producing areas.

Key Words: Asian citrus psyllid, biological control, citrus, Tamarixia radiata

RESUME

La llegada de la enfermedad de los citricos Huanglongbing en Brasil y en Florida, elev6 en
ambas regions a la categoria de plaga clave a su vector Diaphorina citri (Hemiptera: Psy-
llidae). Tres aios despu6s de su aparici6n en Florida se le detect en Puerto Rico, donde su
abundancia parecia ser escasa en comparaci6n, tanto en citricos como en Murraya panicu-
lada, otro hu6sped preferido. Para evaluar sus densidades poblacionales y cuantificar la ac-
ci6n de su ectoparasitoide Tamarixia radiata durante 2004-05 se realizaron muestreos
mensuales en cuatro localidades de la isla. En la localidad mas alta y fria, Adjuntas, no se
observe la presencia de psilidos, a pesar que anteriormente se habia detectado. Se supone
que la ausencia de disponibilidad continue de brotes susceptibles dificult6 a D. citri alcanzar
valores detectables. En cambio en Isabela, la localidad mas calida y costera, donde ademas
los arboles tenian riego, se observe una mayor producci6n de brotes y de D. citri. El parasi-
tismo de estadios maduros de ninfa en esta localidad promedio el 70%, alcanzando el 100%
en 3 ocasiones. Un descenso correspondiente en la infestaci6n de D. citri durante el maximo
de brotes susceptibles indic6 que el parasitoide podria habia contribuido en la regulaci6n de
las poblaciones del vector. Por tanto, un mejor conocimiento de factors favoreciendo el pa-
rasitoide en Puerto Rico podria ayudar a implementar estrategias de control biol6gico mas
efectivas de D. citri en otras zonas citricolas.

Translation provided by the authors.


The Asian citrus psyllid, Diaphorina citri Ku- stages of D. citri develop on newly expanding
wayama, has been reported as an important pest of shoots of citrus and related species of Rutaceae
citrus from tropical and subtropical Asia, Afghani- (Shivankar et al. 2000), although adults can sur-
stan, Saudi Arabia, Reunion, Mauritius, parts of vive for extended periods by feeding on mature
South and Central America, Mexico, and the Carib- leaves (Michaud 2004). In addition to direct feeding
bean (Costa Lima 1942; Wooler et al. 1974; Shivan- damage to plants, D. citri is also an efficient vector
kar et al. 2000; Halbert & Nifiez 2004). Nymphal of the bacterium, Candidatus Liberibacter asiati-







Pluke et al.: Asian Citrus Psyllid Populations and Parasitism


cus and other members of the genus, which cause
greening or "Huanglongbing" disease of citrus
(Catling 1970). The chronic decline in plant health
associated with the pathogen leads to yellow mot-
tled leaves with green banding along the major
veins and fruit that are small, misshaped, and bit-
ter in taste (Halbert & Manjunath 2004; Chung &
Brlansky 2005). Diaphorina citri was first detected
in Guadeloupe and Florida in 1998 (Etienne et al.
1998; Halbert 1998; Halbert et al. 2003) and subse-
quently in Puerto Rico in 2001 (Halbert & Nifiez
2004). The first detection of citrus greening disease
in the Americas occurred in Brazil in 2004 (Coletta-
Filho et al. 2004) and in the United States in south
Florida in Aug 2005 (Halbert 2005).
Tamarixia radiata (Waterson) is an effective
ectoparasitoid ofD. citri nymphs that is credited
with effecting significant control following re-
leases on Reunion and Guadaloupe islands (Aub-
ert & Quilici 1984; Etienne et al. 2001). A single
female of T radiata can deposit up to 300 eggs at
the rate of a single egg per D. citri nymph. The
newly hatched parasitoid larva sucks hemolymph
from the site of attachment to the host which is
eventually killed and consumed.
Classical biological control ofDiaphorina citri
with the parasitoid, T radiata was initiated in
Florida in 1999 (Hoy & Nguyen 2001; Hoy et al.
2004). The parasitoid established and dispersed
quickly and is now found in all the major citrus
growing regions of the State, although generally
at low incidence (Qureshi et al., unpublished data).
Although never intentionally released, T radiata
has been found parasitizingD. citri in Puerto Rico
since 2002 (A. Escribano, personal communica-
tion). It seems likely that both D. citri and T radi-
ata came to the Island on infested orange jasmine
Murraya paniculata (L) a widely used ornamen-
tal shrub locally known as "mirto" or "cafe de la
India." Orange jasmine is grown extensively by
commercial nurseries in Florida. An island-wide
survey in 2004 (R. Pluke, unpublished data) indi-
cated that D. citri was found throughout the is-
land, most commonly on orange jasmine. The
psyllid also was found on various citrus varieties
and another rutaceous ornamental, the limeberry
bush, Triphasia trifolia (Burm. f.) P. Wilson.
A comprehensive survey was required to study
the population trends ofD. citri and assess the con-
tribution of T radiata to mortality of D. citri
nymphs on citrus in Puerto Rico. Therefore, citrus
flushing patterns, and populations ofD. citri and T
radiata were monitored at 4 localities on the island.

MATERIALS AND METHODS

Study Sites

Studies were conducted at 4 agricultural ex-
perimental stations of the University of Puerto
Rico during 2004-2005. The Adjuntas experimen-


tal station (18.16N 66.72W. 608 m) is located in
the western part of the central mountains, prima-
rily a coffee-growing region where a significant
amount of the island's citrus is also found. The Is-
abela experimental station (18.5N 67.02W, 26
m) is on the northern coast and had a variety of
citrus plots as well as a large hedge of orange jas-
mine. There were no other citrus plantings of any
size in the surrounding area, which was com-
prised of some vegetable and seed farms as well
as residential neighborhoods. Corozal experimen-
tal station (18.35N 66.32W, 155 m) is more in
the center of the island, where banana and root
crops are grown on a small scale. There were also
quite a few low density residential areas close to
the experimental station. Gurabo experimental
station (18.25N 65.98W. 68 m) still retains some
of its agricultural origins, a mixture of dairy and
field crops bordering greater San Juan. There was
no significant amount of citrus grown in this re-
gion although orange jasmine was common in all
urban/residential areas. The 4 survey sites had
different stands of citrus present: a 5-yr old or-
ange plot in Adjuntas, (trees 5-10 feet in height),
an irrigated orchard of mixed varieties and ages
in Isabela (trees 6-12 feet in height), a 10-yr old
plot of 'chironja' (a hybrid of orange and manda-
rin) in Corozal (trees 10-15 feet in height), and a
small 5-yr old planting of oranges in Gurabo
(trees 6-12 feet in height). The study blocks did
not receive any irrigation, except the orchard at
Isabela which received some supplemental irriga-
tion during dry periods. No regular insecticidal
spraying of the trees occurred during the year and
the plots were generally kept weed-free. One or 2
applications of dry fertilizer and micronutrients
were made during the year.
Additional samples to evaluate apparent para-
sitism were taken from M. paniculata in Rio Pie-
dras and San Juan. At Rio Piedras, the sampled
plants formed a hedge bordering a pond in the bo-
tanical gardens near the University of Puerto
Rico. In San Juan a similar hedge grew around
the administrative building at the Parque Cen-
tral sporting complex. Both hedges were mini-
mally managed and only occasionally pruned.
There were no citrus plants in close proximity.

Sampling

On each monthly sampling date, 10 trees were
randomly selected and a meter square frame
(quadrat) was randomly placed over an area in the
outer tree canopy. The selected area was exam-
ined to count young flush and the flush infested
with eggs and nymphs ofD. citri. Flush is a newly
developing cluster of very young and feather-
stage leaves on the expanding terminals, pale
green in color and not yet fully hardened, that is
suitable for the psyllid oviposition and nymphal
development. Prior work has shown that oviposi-







Florida Entomologist 91(1)


tion occurs principally on buds and developing
flushes (Catling 1970; EPPO 2005). Therefore,
sampling was restricted to those flushes that sup-
ported oviposition and nymphal development. By
the time flushes had expanded and hardened to a
dark green color, nymphs had completed their de-
velopment. Our characterization of flushes fol-
lowed the categories described in a prior study of
citrus flushes in Puerto Rico (Michaud & Brown-
ing 1999). Flush development at Isabela was ex-
amined more regularly by making weekly visits.
For each tree, the percentage of flushes with
psyllid eggs or nymphs present in the 1-m2 quad-
rat was noted. Relative infestation rates were cal-
culated by multiplying flush density (i.e., number
of developing flushes/m2) by the proportion of
flush infested with D. citri eggs and nymphs. Ad-
ditionally, a score of 1 to 5 was assigned to a com-
bined number of all instars representing follow-
ing density ranges: 1 = 0-5, 2 = 6-15, 3 = 16-50, 4
= 51-100, and 5 = 100+ per flush. One density
score was given to each of the 10 trees on each
sampling date.
A sample of third to fifth psyllid instars was
collected from different trees and different loca-
tions in a tree at each study site and taken to the
laboratory to assess T radiata parasitism. The
psyllid-infested flushes were put into a container,
dated, and placed into an incubator at 27C. After
14 d, the container was transferred to a freezer to
kill any live insects. The container was then
opened and the number of D. citri and T radiata
adults counted. Adult counts ofD. citri and T ra-
diata were used to calculate apparent parasitism
rates (Stansly et al. 1997). Late psyllid instars on
orange jasmine in Rio Piedras and San Juan also
were collected by the methodology described
above. In Rio Piedras, nymphs were collected in
Jun, Aug, Sep, Oct, and Dec in 2004, and in Jan,
Mar, and May in 2005. In San Juan, nymphs were
collected in Jul, Sep, Oct, and Dec in 2004, and in
Feb-Jun in 2005. Nymphs were collected only
once from the hedge of orange jasmine at Isabela.
Data on flush density and incidence of D. citri
were subjected to analysis of variance (ANOVA),
and means were separated by the least significant
(LSD) test in the event of a significant F value
(SAS 1999-2001). Flush infestation data were arc-
sine transformed before ANOVA. Residuals were
analyzed for normality by using stem and leaf
plots. Temperature and rainfall data were col-
lected at all 4 research stations.

RESULTS


Weather Patterns


Minimum temperatures reported by the exper-
iment stations averaged 18.5C and maximum
temperatures 29.2C over the 4 study sites (Fig.
1). Lowest temperatures were recorded at Adjun-


Rainfall (cm) -e-Min(C) --Max (C)
60
A
S50 50
L 40 40
L 30 a 30 |
S20 20
t 10 10

ONDM J J
0 N D J F M A M J J A


ONDJ FMAM J J A


OND J FMA M J J A


ONDJ F M A M J J A
2004-2005
Fig. 1.
Monthly mean temperature ( C) and rainfall (cm) at (A)
Isabela, (B) Corozil, (C) Gurabo, and (D) Adjuntas dur-
ing the study period in 2004-2005.


tas, especially minimum temperatures which av-
eraged almost 5C below the other 3 sites. Diur-
nal extremes were also greatest at Adjuntas, av-


March 2008







Pluke et al.: Asian Citrus Psyllid Populations and Parasitism


eraging 14C compared to 8C at Isabela. Rainfall
averaged 204 cm over all 4 sites, and was greatest
at Corozal, exceeding the other locations by 52
cm. Feb and Mar were the driest months at all
sites with varying rainfall patterns during the
rest of the year.

Citrus Flushing Patterns

Overall flush density was greater at Isabela
and Gurabo than Corozil and Adjuntas with no
difference between high density locations or be-
tween low density locations (F = 6.62, df = 3, P =
0.0002, Table 1). A peak in spring flush was ob-
served in Feb and Mar at Adjuntas and Corozal,
respectively, and in Apr at Isabela and Gurabo
(Fig. 2A). However, the peak was more pro-
nounced at Isabela and Gurabo. Another peak in
flush density was observed during summer in Jul
at all the four sites. Flush was more abundant in
spring than summer and there was very little
flush activity observed outside these intervals.

Psyllid Populations

Diaphorina citri was present at Isabela,
Corozil, and Gurabo but absent at Adjuntas. Per-
centage of infested flush, relative infestation rates,
and psyllid density scores were all significantly
different among locations (F = 25.08, 14.71, 18.45;
df = 2, 2, 2; P = <0.0001, <0.0001, <0.0001, respec-
tively, Table 1). Overall, all 3 measures of psyllid
abundance were higher at Isabela than Corozil
and Gurabo with no significant differences be-
tween the latter locations. Percentage of infested
flush was significantly higher at Isabela than at
Corozil and Gurabo in Oct, Jan, Feb, and Mar
with similar trends at other times (Fig. 2B). The
percentage of infested flush was greatest in Feb
(69%) at Isabela, and in Apr at both Corozil and
Gurabo (52% and 22%, respectively). Flush infes-
tation did not differ between Corozil and Gurabo
in any month. The monthly results of relative in-
festation rates are not reported because they were


similar to the ones obtained from data on percent
flush infestation except in Dec, when infestation
rate was higher at Isabela than Corozal and
Gurabo, with no difference between the latter
sites. Although, flush density was not different
among sites in Dec. Density of D. citri nymphs
based on the density scores also differed among lo-
cations and was generally higher at Isabela than
at Corozal and Gurabo (Fig. 2C). In Oct and Dec,
D. citri density was higher at Isabela than Gurabo
and both sites did not differ from Corozal in either
month. In Jan and Feb, D. citri density was higher
at Isabela than both Corozal and Gurabo with no
difference between the latter sites in either month.
In Apr, D. citri density was higher at Isabela and
Corozal than observed at Gurabo with no differ-
ence between the former sites.

Incidence of Parasitism

Tamarixia radiata was found parasitizing D.
citri nymphs in citrus at all 3 survey sites where
the psyllid was found (Fig. 3). Mean percentage
apparent parasitism was highest (70 8%) and
most consistent at Isabela compared with Corozal
(38 10%) and Gurabo (39 10%). Parasitism at
Isabela generally exceeded 50%, and was gener-
ally higher and less variable than at Corozal and
Gurabo.
Tamarixia radiata also was found parasitizing
D. citri nymphs in orange jasmine. In Rio Piedras,
parasitism was 100% in Jun (n = 7), 50% in Aug (n
= 16), 38% in Oct (n = 13) 2004, and 100% in May
(n = 4) 2005 although undetectable in Sept (n = 7),
Jan (n = 1), and Mar (n = 1). No adults ofD. citri
or T radiata emerged in Dec 2004. In San Juan,
parasitism was 67% in Jul (n = 12), 92% in Dec (n
= 24) 2004, and 100% in Feb, Mar, and Apr (n =
39, 11, 44, respectively), 93% in May (n = 30), and
71% in Jun (n = 14) 2005 though again undetect-
able in Sept (n = 5). No adults ofD. citri or T ra-
diata emerged in Oct 2004. Parasitism was 50%
from one-time collection of nymphs made in Jun
in the orange jasmine hedge at Isabela.


TABLE 1. OVERALL INFESTATION AND INCIDENCE OF DIAPHORINA CITRI EGGS AND NYMPHS (MEAN SEM) AT THE 4
STUDY SITES IN PUERTO RICO DURING 2004-2005.

Incidence of Diaphorina citri /m2
Flush density
Study sites no./m2 Infested flush (%) Infestation rate/m2 (no.)a Density index (no.)b

Isabela 14.0 2.43 a 31.0 3.32 a 7.14 1.59 a 1.13 + 0.11 a
Corozil 7.1 0.98 b 14.2 2.60 b 1.18 + 0.27 b 0.65 0.09 b
Gurabo 11.6 2.23 a 8.2 1.76 b 1.97 0.73 b 0.46 0.09 b
Adjuntas 7.6 1.16 b -

"Infestation rate is obtained by multiplying number of flushes per m and proportion of flush infested with eggs and nymphs.
bDensity index is based on the density scores that ranged from 1 to 5 and represent combined density of all instars, i.e., 1 = 0-5,
2 = 6-15, 3 = 16-50, 4 = 51-100, and 5 = 100+ nymphs per flush.







Florida Entomologist 91(1)


-e-sabela --Corozal --Gurabo -Adjuntas
A


O N D J F MA M J J A


March 2008


45


SbIsabela

22 21 26


0 '{ |1 11


J A S O ND J F MA M J J A
3 3 Corozal I


20




2 I


2A


2 A


J ASONDJ F M A M J J A


O N D J F M A M J J A


I Gurabo
26 45
28 45



23 31 4


s





hA


J ASOND J F M A M J J A


O N D J F M A M J J A
2004-2005

Fig. 2. Mean SEM (A) number of young citrus
flushes per meter square, (B) percentage of flush in-
fested with D. citri eggs and nymphs, and (C) density
score representing density of D. citri eggs and nymphs
at the 4 study sites in Puerto Rico during 2004-2005.
Density score ranged from 1 to 5 and represented the
combined numbers of all instars in the following ranges,
1 = 0-5, 2 = 6-15, 3 = 16-50, 4 = 51-100, and 5 = 100+
nymphs per flush. Asterisks indicate differences among
the locations during the marked month for a particular
variable. Diaphorina citri was not found at the sam-
pling location in Adjuntas.



DISCUSSION

Most new foliage production at all 4 sites oc-
curred during the spring and to a lesser extent in
summer, which conforms to the usual flush pat-
terns. Spring is the time of the year when trees
produced greatest amount of flush. In this study,
it was limited to Feb, Mar, and Apr at Adjuntas,
Corozil, and Gurabo, respectively, but spanned
these months in Isabela. Flush events were char-
acterized by a one- to two-month period of shoot
initiation and growth that was somewhat uniform


2004-2005
Fig. 3. Percent ofDiaphorina citri nymphs (3-5th in-
stars) parasitized by Tamarixia radiata at Isabela,
Corozal, and Gurabo, in Puerto Rico during 2004-2005.
The black triangles indicate samples where neither D.
citri adults nor T radiata adults emerged. Numbers on
the bars represent total number of adults of D. citri and
T radiata that emerged and were used to calculate par-
asitism rates.


in that most of the new flushes on a particular
tree at a given time were of a similar developmen-
tal stage. More frequent observations at Isabela
indicated that it takes about 2 weeks for shoot de-
velopment from flush initiation to leaf maturity.
The trees at Isabela, Gurabo, and Adjuntas were
smaller compared to the trees at Corozal; how-
ever, only Isabela and Gurabo sites had more
flush compared to Corozal, providing more re-
sources for psyllids. Thus, of the sites with psyl-
lids, the one with least flush (Corozal) had fewest
psyllids, in contrast to Isabela with the greatest
and most prolonged densities of flush and psyl-
lids. The trees at Adjuntas did not flush at the
same rate, probably due to the cooler conditions
and mix of varieties with different flush patterns.
Since the criteria to choose flush for sampling was
the same throughout the study and flush was
available across sites at similar times, we believe
that adult psyllids and nymphs had a fair chance
to oviposit and develop.







Pluke et al.: Asian Citrus Psyllid Populations and Parasitism


Although D. citri was first discovered almost
simultaneously in Adjuntas and Isabela in May,
2001 (P Stansly, unpublished data), none was
found this time at the former location. Monthly
inspections of some other citrus plantings at the
experimental station led to a single detection of
the insect during the survey period. Also during
this time, low numbers of all life stages ofD. citri
were found in 2 locations in a nearby commercial
citrus grove about 16 km from the experiment
station. Some of these nymphs were parasitized.
Evidence from the searches in and around the Ad-
juntas experimental station suggests that the in-
sect has spread but not flourished in the high-
lands. One can only suppose that the combination
of a cool, dry winter, and a coincident short flush-
ing season was somehow responsible for this scar-
city. The optimum temperature range for D. citri
development is 25-28C (Liu & Tsai 2000), higher
than the minimum temperatures found at Adjun-
tas throughout the year.
At the Isabela, Corozal and Gurabo sites, all
stages of D. citri were present throughout the
year, even when there was little flush. However,
psyllid populations showed an increasing trend
with flush density and thus were greater at Isa-
bela compared to Corozal and Gurabo. At all loca-
tions, greatest density of flush and psyllids oc-
curred during the spring. It is difficult to attribute
observed differences in flushing patterns and
psyllid incidence solely to environmental factors,
especially in comparing Isabela and Corozil
where weather conditions during the study period
were so similar. However, there was more citrus
at Isabela than the other 2 sites, and it was irri-
gated during the dry months of Feb and Mar. This
irrigation was probably responsible for the earlier
and more ample flush observed, which provided
greater resources for psyllids and more time for
host and parasitoid populations to stabilize. An-
other factor favoring psyllids and parasitoids at
Isabela may have been the nearby hedge of or-
ange jasmine that flushed continuously due to fre-
quent pruning, and thus may have provided a ha-
ven when citrus was not available. In comparison,
populations ofD. citri at Corozil and Gurabo were
subjected to a more limited food supply and there-
fore were smaller and more variable. There also
were no nearby hedges of orange jasmine to pro-
vide refuge for psyllids.
Psyllid populations started to decline in Isa-
bela after Feb in concert with consistently high
rates (75% or more) of parasitism by T radiata.
The inability of psyllid populations to continue in-
creasing in response to the increased flush in Apr
at Isabela suggested that T radiata may have
played a significant role in regulating D. citri
there. Although sampled only once, T radiata was
parasitizing 50% of the nymphs in the nearby
hedge of orange jasmine. It is likely that those
populations contributed to the effects observed in


citrus. At Corozil and Gurabo, D. citri population
peaks correlated more closely with a shorter and
smaller flush in Mar-Apr, indicating a more re-
source limited abundance pattern, although rela-
tively high levels of parasitism likely had an im-
pact as well. Generally high rates of parasitism by
T radiata on psyllid nymphs in orange jasmine at
Rio Piedras and San Juan also support that the
parasitoid was actually making significant contri-
bution to the mortality of psyllid nymphs in Pu-
erto Rico. Several other factors such as fungus and
predators particularly ladybeetles are known to
contribute to psyllid mortality (Halbert & Manju-
nath 2004). However, we did not see psyllid adults
or nymphs killed by fungus in citrus although
some psyllid mortality due to fungus was occasion-
ally observed in orange jasmine at Rio Piedras.
Only 2 coccinellids Coelophora inaequalis F. and
Cycloneda sanguine limbifer L., predominated
the citrus groves. However, both of these species
have been shown to prefer the brown citrus aphid
over the psyllid in Puerto Rico (Pluke et al. 2005).
Tamarixia radiata was found together with
D. citri at almost all times and locations in Puerto
Rico, at an incidence relative to the availability of
its host. The parasitoid was present year round at
Isabela with the exception of Nov 2004 when
D. citri populations were at their lowest ebb. Par-
asitism at Corozil and Gurabo was less predict-
able, reflecting lower psyllid populations and pos-
sibly the local paucity of host plants. Neverthe-
less, apparent parasitism rates were high at all
3 of these sites compared to generally low (<20%)
and variable rates observed in commercial citrus
groves in Florida (Qureshi et al., unpublished
data). This contrast suggests that environmental
or ecological factors are more favorable for T ra-
diata in Puerto Rico, or that the biological and ge-
netic characteristics of the parasitoid in the two
areas are somehow different.
The apparent parasitism rates estimated in the
study were meant to serve only as a relative index
of parasitoid activity, and not as a measure of co-
hort mortality. Our methods would not have taken
into account other mortality factors such as preda-
tion, which are probably responsible for additional
mortality, especially of younger instars (Michaud
2004; Qureshi & Stansly 2007). Another factor af-
fecting the estimate could be the likely lower sur-
vivorship of still-feeding psyllid nymphs compared
to parasitoids once shoots have been removed
from the tree. However, the comparison within
sites in Puerto Rico and with Florida is valid be-
cause the same methods were used to evaluate in-
cidence of parasitism for all. However, the degree
to which parasitism is responsible for regulation
of psyllid populations at this location would re-
quire a more detailed life table analysis. In lieu of
that, we can speculate that the consistent decline
in psyllid populations and consistently high par-
asitism rates by T radiata at Isabela after Feb











suggest that the parasitoid was making a signifi-
cant contribution to regulation of psyllid popula-
tions. Additionally, high parasitism rates in citrus
at Gurabo and Corozil and in orange jasmine at
Rio Piedras and San Juan also support this con-
clusion. Tamarixia radiata also was credited for
significant reduction in psyllid populations in
Reunion, where it was intentionally released (Eti-
enne et al. 2001). The apparent lack of similar re-
sults in Florida require further studies.


REFERENCES CITED

AUBERT B., AND S. QUILICI. 1984. Biological control of
the African and Asian citrus psyllids (Homoptera:
Psylloidea), through eulophid and encyrtid parasites
(Hymenoptera: Chalcidoidea) in Reunion Island, pp.
100-108 In S. M. Garnsey, L. W. Timmer, and J. A.
Dodds [eds.], Proc. 9th Conference of the Interna-
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CATLING, H. D. 1970. Distribution of the psyllid vectors
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CHUNG, K. R., AND R. H. BRLANSKY. 2005. Citrus dis-
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stitute of Food and Agricultural Sciences, University
of Florida. http://edis.ifas.ufl.edu/PP133
COLETTA-FILHO, H. D., M. L. P. N. TARGON, M. A. TAK-
ITA, J. D. DE NEGRI, J. POMPEU, JR., M. A. MACHADO,
A. M. Do AMARAL, AND G. W. MULLER. 2004. First re-
port of the causal agent of Huanglongbing ("Candi-
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COSTA LIMA, A. M. DA. 1942. Homopteros. Insetos do
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ETIENNE, J., D. BURCKHARDT, AND C. GRAPIN. 1998. Di-
aphorina citri (Kuwayama) [sic] en Guadeloupe, pre-
mier signalement pour les Caraibes (Hem.,
Psyllidae). Bull. Soci6t6 Entomologique de France.
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ETIENNE J., S. QUILICI, D. MARIVAL, AND A. FRANCK.
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rixia radiata (Hymenoptera: Eulophidae). Fruits.
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HALBERT, S. E. 1998. Entomology section. Tri-ology
(May-June 1998) 37: 6-7.
HALBERT, S. E., C. L. NIBLETT, K. L. MANJUNATH, R. F.
LEE, AND L. G. BROWN. 2003. Establishment of two


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new vectors of citrus pathogens in Florida, pp. 1016-
1017 In Proc. International Soc. Citriculture IX Con-
gress, ASHS Press, Alexandria, VA, USA.
HALBERT, S. E., AND C. A. NU1EZ. 2004. Distribution of
the Asian citrus psyllid, Diaphorina citri Kuwayama
(Rhynchota: Psyllidae) in the Caribbean Basin. Fla.
Entomol. 87: 401-402.
HALBERT, S. E., AND K. L. MANJUNATH. 2004. Asian cit-
rus psyllids (Sternorrhyncha: Psyllidae) and green-
ing disease of citrus: a literature review and
assessment of risk in Florida. Florida Entomol. 87:
330-353.
HALBERT, S. E. 2005. Pest Alert: Citrus Greening/Huang-
longbing. Florida Department of Agriculture and
Consumer Services. Department of Plant Industry.
http://www.doacs.state.fl.us/pi/enpp/ento/citrus-
greeningalert.html.
HoY, M. A, AND R. NGUYEN. 2001. Classical biological
control of Asian citrus psylla. Citrus Ind. 81: 48-50.
HoY, M. A., R. NGUYEN, AND A. JEYAPRAKASH. 2004.
Classical biological control of Asian citrus psyllid in
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rus/citrus_psyllid.htm
LIU, Y. H., AND J. H. TSAI. 2000. Effects of temperature
on biology and life table parameters of the Asian cit-
rus psyllid, Diaphorina citri Kuwayama (Homop-
tera: Psyllidae). Ann. Appl. Biol. 137: 201-206.
MICHAUD, J. P. 2004. Natural mortality of Asian citrus
psyllid (Homoptera: Psyllidae) in central Florida.
Biol. Contr. 29: 260-269.
MICHAUD, J. P., AND H. W. BROWNING. 1999. Seasonal
abundance of the brown citrus aphid, Toxoptera cit-
ricida (Homoptera: Aphididae) and its natural ene-
mies in Puerto Rico. Florida Entomol. 82: 424-447.
PLUKE, R. W. H., A. ESCRIBANO, J. P. MICHAUD, AND
P. A. STANSLY. 2005. Potential impact of ladybeetles
on Diaphorina citri (Homoptera: Psyllidae) in Pu-
erto Rico. Florida Entomol. 88: 123-128.
QURESHI, J. A., AND P. A. STANSLY. 2007. Integrated ap-
proaches for managing the Asian citrus psyllid Dia-
phorina citri (Homoptera: Psyllidae) in Florida, In E.
Etxeberria [ed.], Proc. Florida State Hort. Soc. 120:
110-115.
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ies on citrus psylla, Diaphorina citri Kuwayama: a
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parent parasitism of Bemisia argentifolii (Homop-
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citri on citrus. FAO Plant Prot. Bull. 22: 93-94.


Florida Entomologist 91(1)







Gagn6 et al.: A New Cecidomyiid Preying on Avocado Lace Bug


A NEW LESTODIPLOSINE (DIPTERA: CECIDOMYIIDAE) PREYING
ON THE AVOCADO LACE BUG, PSEUDACYSTA PERSEAE
(HETEROPTERA: TINGIDAE) IN SOUTHERN FLORIDA

RAYMOND J. GAGNE1, JORGE E. PENA2 AND FLOOR E. ACEVEDO
'Systematic Entomology Laboratory, PSI, Agricultural Research Service, U.S. Department of Agriculture,
c/o Smithsonian Institution MRC-168, P.O. Box 37012, Washington, D.C. 20013-7012, USA
E-mail: rgagne@sel.barc.usda.gov)

2University of Florida, Tropical Research and Education Center, 18905 S.W. 280th St., Homestead, FL 33031

ABSTRACT

A species new to science, Tingidoletes praelonga Gagn6 (Diptera: Cecidomyiidae), was re-
cently discovered preying on the avocado lace bug, Pseudacysta perseae (Heidemann) (Het-
eroptera: Tingidae), in Florida, USA. A new genus is described to receive the new species.

Key words: gall midge, predator, avocado lace bug, Persea americana

RESUME
Una especie nueva para la ciencia, Tingidoletes praelonga Gagn6 (Diptera: Cecidomyiidae),
fu6 descubierta recientemente depredando la chinche del aguacate, Pseudacysta perseae
(Heidemann) (Heteroptera: Tingidae), en Florida, USA. Se describe un nuevo g6nero que
acoge la nueva especie.


Translation provided by the authors.


An undescribed cecidomyiid was discovered in
Miami-Dade Co., Florida, during a survey for
predators of the avocado lace bug, Pseudacysta
perseae (Heidemann), a native pest of avocados,
Persea americana, and redbay, Persea borbonia, in
the USA. The avocado lace bug was considered a
minor pest of avocados until the mid-1990s. Per-
sistent outbreaks of this insect have been ob-
served in Florida and in the Caribbean region
since 1990 (Medina-Gaud et al. 1991; Abud-An-
tun 1991). In the United States the avocado lace
bug is currently known from Florida and Georgia
and more recently in California. It also is known
from Bermuda, Dominican Republic, Puerto Rico,
Mexico, Cuba, Surinam, and Venezuela (Mead &
Pefia 1991; Sandoval 2004; Morales, unpubl.). A
survey for predators of this pest undertaken in
Florida from 1995 through 1997 found several im-
portant natural enemies of this pest (Pefia et al.
1998), but only in a recent survey was the new ce-
cidomyiid discovered by one of us (FA) preying on
nymphs of P perseae.
Single eggs were observed among colonies of
P perseae on avocado. Newly hatched amber-col-
ored larvae crawled to the lace bugs and inserted
their mouthparts usually under the more anterior
abdominal segments (Figs. 1 and 2). After their
initial feeding, larvae turned reddish-orange.
Larvae were commonly observed feeding in a po-
sition perpendicular to the prey. A larva was once
found with its mouthparts inserted into the distal


antennal segment of an immobilized third instar.
Larvae appeared more often to feed on lace bug
nymphs, but larger larvae were also observed
feeding on lace bug adults. When full grown, lar-
vae spun orange-colored cocoons close to the leaf
midvein (Fig. 3). Adults (Fig. 4) emerged 6-8 d
later and lived 2-4 d under laboratory conditions.

MATERIALS AND METHODS

To obtain adults of the predator, older larvae
were placed in petri dishes with lace bug nymphs
so the larvae could be fully fed when they formed
their cocoons. Immature stages and adults were
preserved in 70% isopropyl alcohol. Specimens
were mounted on microscope slides following the
method outlined in Gagne (1989). Terminology for
adult morphology follows usage in McAlpine et al.
(1981) and for larval morphology that in Gagne
(1989). The discovery of the new species and fur-
ther study of its biology were made by JEP and
FA, and the taxonomy of the new taxon was done
by RJG.

Tingidoletes Gagn6, new genus

Adult (Fig. 4).-Head: Eyes large, connate, eye
bridge 12 facets long; all eye facets hexagonal and
closely adjacent to one another. Occiput with
short, blunt dorsal protuberance with pair of
large, elongate setae. Antenna with 12 flagellom-







Florida Entomologist 91(1)


Figs. 1-4. Tingidoletes praelonga. 1, Larva feeding on nymph of avocado lace bug. 2, Larva feeding on adult av-
ocado lace bug. 3, Cocoon. 4, Male.


March 2008







Gagn6 et al.: A New Cecidomyiid Preying on Avocado Lace Bug


eres, the first and second flagellomeres partly con-
nate. Male flagellomeres (Figs. 6-7) binodal, basal
node spherical with single circumfilum, distal
node longer, cylindrical, with 2 circumfila, both
nodes with more setae dorsally than ventrally, the
setae all of generally similar length; loops of basal
and middle circumfila of each flagellomere greatly
uneven in length, 1 loop of each originating on
dorsolateral flagellomere surface longer than en-
tire flagellomere, the remaining loops of uneven
length but much shorter, not reaching next node;
distal circumfilum on each flagellomere with
loops of slightly uneven length, none reaching
apex of flagellomere. Female flagellomeres (Fig. 8)
cylindrical with short necks, with more setae dor-
sally than ventrally, and 2 horizontal circumfila
connected by 2 vertical strands. Frons with sparse
setae and no scales. Labella covered mesad with
fine, elongate setulae (Fig. 14). Hypoproct ringed
along outer edge with long, wide setulae (Fig. 14).
Palpus 4-segmented.
Thorax: Notum with 4 longitudinal rows of se-
tae and no scales. Pleura with vestiture only on
anepimeron. Wing (Fig. 5): C broken posteriad of
its junction with R5; R5 slightly curved apically,
joining wing just below apex; Cu forked. Legs elon-
gate, thin, about 1 1/2 times as long as wing. Acro-
pods (Figs. 9-10): claws strongly curved just beyond
midlength, with basal tooth on fore- and midlegs,
without tooth on hindlegs; empodia reaching curve
of claws; pulvilli short, about 1/4 length of claws.
Male Abdomen (Figs. 13, 15-16): First tergite
rectangular with single, sparse row of posterior
setae and pair of anterior trichoid sensilla. Second
through sixth tergites short-rectangular, with sin-
gle, sparse posterior row of setae, 1-3 lateral setae
on each side, a pair of anterior trichoid sensilla,
and elsewhere with evenly distributed scales; sev-
enth and eighth tergites unpigmented, their only
vestiture the anterior pair of trichoid sensilla.
Sternites second through sixth with single row of
posterior setae, 2 rows of setae at midlength, and
2 closely adjacent trichoid sensilla anteriorly; sev-
enth as for sixth except narrower and the trichoid
sensilla widely separated; eighth with no to sev-
eral posterior setae and widely separated pair of
anterior trichoid sensilla. Genitalia (Figs. 15-16):
Cerci convex apically, each with several apical and
apicoventral setae; hypoproct gradually widening
from midlength to apex, posterior edge nearly
straight across, with several apical and apicoven-
tral setae; aedeagus dorsoventrally flattened, in
dorsoventral view widest near midlength, the
apex convex, 3 pairs of papillae present on each
side; gonocoxite thickset at base, with cylindrical,
apically rounded, elongate-setulose mesal lobe;
gonostylus broadest at base, tapering to apical
tooth, setulose on basal half, ridged beyond.
Female Abdomen (Figs. 11-12): First through
seventh tergites as for first through sixth in male,
but seventh more diminutive than sixth; eighth


No o
\ 6 7




9 10
8
Figs. 5-10. Tingidoletes praelonga. 5, Wing. 6, Male
third antennal flagellomere (dorsal). 7, Same. (ventral).
8, Female third antennal flagellomere. 9, Acropod of
foreleg. 10, Acropod of hindleg.


tergite not pigmented, demarcated only by anterior
pair of trichoid sensilla. Sternites 2 through 7 as for
male except for the mostly double posterior row of
setae; sternite 8 undefined except for the widely
separated anterior pair of trichoid sensilla. Tenth
tergum with several posterior setae. Tenth sternum
with a large group of setae on each side. Cercus se-
tose, with posterior pair of large peglike setae, set-
ulose throughout. Hypoproct as wide as long, with a
pair of apical setae, setulose throughout.
Larva, Third Instar (Figs. 17-18).-Head cap-
sule conical, antenna more than 3 times as long as
basal width, apodemes as long as head capsule.
Integument dorsally and laterally smooth, ven-
trally on anterior half of each segment with 4 con-
vexities (traction pads) covered with rounded ver-
rucae, posterior half smooth. Spatula (Fig. 17)
with 2 rounded anterior lobes and elongate shaft.
Anus located dorsoposteriorly. Papillae on venter
difficult to detect, but 2 triplets evident on each
side of spatula. Dorsal papillae with short, cylin-
drical, blunt-tipped setae, pleural papillae with
setae of same length but more pointed. Terminal
segment with 4 papillae on each side, 1 of each
group with short, cylindrical, blunt-tipped seta,
the remainder low-convex, without setae.







Florida Entomologist 91(1)


15 16


1~- -. y-


S" 13 14



Figs. 11-14. Tingidoletes praelonga. 11, Female ab-
domen, sixth segment to cerci (lateral). 12, Same, detail
of female tenth segment and cerci (lateral). 13, Male ab-
domen, fifth through eighth segments (lateral). 14,
Adult mouthparts (lateral).



Type Species: Tingidoletes praelonga Gagne.
Etymology.-The generic name Tingidoletes is
Latin for "predator of tingids." The name is con-
sidered feminine.
Remarks.-Tingidoletes belongs to the super-
tribe Cecidomyiidi where it can be subsumed with
most other cecidomyiid predators within the tribe
Lestodiplosini as defined in Gagne (1994). The larva
of the new genus is distinctive and unusual among
Lestodiplosini for its short, thick, cylindrical setae
on the dorsal papillae and the makeup of the termi-
nal papillae of which 3 pairs have no setae and 1
pair has thick, short, and blunt setae similar to
those on the dorsal papillae (Fig. 18). The only gen-
erally similar predaceous larva known to date is
that ofTrilobia aphidisuga Del Guercio, a European
predator of aphids known from the original descrip-
tion of the larval stage alone (Harris 1973). The
form of its terminal papillae appears generally sim-
ilar to that of T praelonga, except that the end of the
setose pair is tapered instead of blunt. The shape of
the setae on the dorsal papillae of T aphidisuga re-
mains undescribed. It is possible that Trilobia could
serve as a generic name for the new species, but
without adults we cannot know.
Tingidoletes will run to Aphidoletes in couplet
102 in the key to Nearctic genera in Gagne (1981a),
offering a good illustration that characters effec-
tive for use in keys, in this case the presence of


17 18
Figs. 15-18. Tingidoletes praelonga. 15, Male gono-
pod, hypoproct and aedeagus (dorsal). 16, Male gonocox-
ite, cerci, hypoproct and aedeagus (lateral). 17, Larval
head and collar and prothoracic segments (ventral). 18,
Larval seventh to terminal abdominal segments (dorsal).


teeth on the tarsal claws and an extremely long cir-
cumfilar loop on each node of the male flagellom-
eres, are not necessarily a measure of propinquity.
Aphidoletes is a genus of 3 species whose larvae are
external predators of aphidoids. The 2 genera dif-
fer most conspicuously in that the adult abdomen
of Tingidoletes is fusiform instead of evenly cylin-
drical, is much shorter due to the foreshortened in-
stead of primatively large, rectangular sclerites,
has lost most of the tergal lateral setae, and the
male seventh tergite is membranous and without
vestiture except for the anterior pair of trichoid
sensilla. The genitalia also are very different; those
of Aphidoletes are much more complex (Harris
1966) than those of Tingidoletes (Figs. 15-16).
The presence of greatly elongate individual cir-
cumfilar loops on the antenna of both genera is
only a superficial similarity. The enlarged circum-
filar loops ofAphidoletes are on the basal and dis-
tal circumfila of each flagellomere, while those of
Tingidoletes are on the basal and middle loops.
Also, unlike in Aphidoletes, Tingidoletes does not
have a greatly elongate seta situated next to the
long circumfilar loop. That the middle circumfi-
lum is very long is extraordinary because in the
supertribe Cecidomyiidi generally the second cir-
cumfilum is generally the first to undergo reduc-
tion or complete loss, e.g., in Bremia, most Con-
tarinia (Gagne 1994), and some Lestodiplosis


March 2008


12







Gagn6 et al.: A New Cecidomyiid Preying on Avocado Lace Bug


(Harris 1973). An exception brought to our atten-
tion by K. M. Harris is Lestodiplosis irregularifila
Kashyap (1989) in which that middle circumfilum
also has 1 elongated loop.
As a rule more setae and circumfilar loops of
gall midges are disposed on the ventral half of the
flagellomeres. The significance of that arrange-
ment, we suppose, is optimal sensory perception
because the ventral surface of the antenna is the
leading edge during flight (Fig. 4). Yet, where
greatly elongated loops of circumfila occur, as in
Aphidoletes and Bremia (Harris 1966), Thripsobre-
mia (Gagne & Bennett 1993), Lestodiplosis (Gagne
& Lill 1999) and the new genus, they are always on
the dorsolateral flagellomere surface (Fig. 6). That
placement makes long loops less likely to fold or to
collide during flight with the corresponding cir-
cumfila of the other antenna. Elongate circumfilar
loops appear in several predaceous and presum-
ably predaceous genera, but their significance is
unknown. Inasmuch as it is the female that
searches for the host, it would appear the male
needs its antennal sensoria only to find females. A
remarkable antennal feature that can be seen in
Fig. 4 is that with the antennae arched almost in a
circle, the elongated circumfilar strands are evenly
disposed radially. Possibly this arrangement am-
plifies the sensory capability of the antennae.
The mediolateral lobe of the male gonostylus of
Tingidoletes is reminiscent of those found in
Lestodiplosis and Thripsobremia (Gagne & Ben-
nett 1993), but in those genera, the female
flagellomere necks are at least twice as long as
wide, and the female cerci have on their venter a
field of closely placed, very short sensilla. Tingi-
doletes females have flagellomere necks that are
no longer than wide and lack the group of short,
ventral sensilla on the cerci.
The male hypoproct and aedeagus of Tingid-
iplosis are similar in shape to those of Endaphis
spp. (Tang et al. 1994; Gagne 1981b), internal
predators of aphids, and of Silvestriola cincta, a
mite predator (Gagne 1994), but that resem-
blance is only superficial when other head charac-
ters are taken into account. Endaphis and Silves-
triola have circular eye facets that are sparser at
eye midheight, while Tingidoletes has eyes of con-
siderably greater extent with entirely hexagonal,
closely juxtaposed facets. Further, both Silves-
trina and Endaphis lack a dorsal occipital protu-
berance, a distinctive character in Tingidoletes.

Tingidoletes praelonga Gagn6

Adult.-Head: Antennal flagellomeres as in
Figs. 6-8. Frons with 3-5 setae per side. Mouth-
parts as in Fig. 14, setae ringing the hypoproct
long and strong. Labella hemispherical in lateral
view, each with 6-8 lateral setae.
Thorax: Wing (Fig. 5): without markings;
length: male, 1.4-1.6 mm (n = 4); female, 1.4-1.6


mm (n = 3). Notum with sparse setae; scutellum
with 3-5 setae on each side and 4-5 anteromedi-
ally; anepimeron with 6-8 setae. Acropods as in
Figs. 9-10, fore- and midclaws toothed, the hind
claws simple. Male abdomen as in Figs. 13, 15-16.
Female abdomen as in Figs. 11-12.
Holotype.-Male, Homestead Florida, X-10-
2006, F.E. Acevedo, deposited in USNM.
Other Specimens Examined.-Six adults, all
from Homestead, Florida, reared by F.E. Acevedo
on the following dates: 2 males, IX-24-2006; 1 fe-
male, X-8-2006; 1 female, X-10-2006; 1 female, X-
14-2006; 1 female, X-20-2006. Seven larvae, Home-
stead, Florida, XI-30-2006, J. E. Peia & D. Long.
Etymology.-The specific name praelonga is a
Latin adjective meaning very long. In the present
case, the name refers to the 2 elongate circumfilar
strands on each of the male flagellomeres.
Remarks.-This is the only species of Cecid-
omyiidi with a greatly enlarged middle circumfi-
lum on the male flagellomeres and short, stubby
dorsal larval papillae. A single pair of terminal
larval papillae has setae, a condition known else-
where only in Trilobia aphidisuga, in which they
are conical instead of cylindrical.

SUMMARY

Insect larvae of Cecidomyiidae were discov-
ered preying on the avocado lace bug, a great pest
of avocado in Florida and elsewhere in the Amer-
ican tropics. The predator was determined to be a
species new to science that is apparently a natu-
ral control of the lace bug. The new insect is de-
scribed and a new genus is erected to receive it.
This report classifies the species in its proper
place, will allow identification of the species in the
future, and make the information available to the
scientific community.

ACKNOWLEDGMENTS

We thank P. Malikul for making the slide prepara-
tions, D. Long for help with collections of specimens,
and M. Metz for setting the illustrations onto plates. We
are grateful to K. M. Harris, David A. Nickle, Allen L.
Norrbom, and an anonymous reviewer for comments on
drafts of the manuscript.

REFERENCES CITED
ABUD-AUTUN, A. 1991. Presence of avocado lace bug,
Pseudacysta perseae (Heidemann) in Dominican Re-
public. Primera Jornada de Protecci6n Vegetal, Uni-
versidad de Santo Domingo, Dominican Republic. p.
4. (Abstract).
GAGNE, R. J. 1981a. Cecidomyiidae, pp. 257-292 In J. F.
McAlpine, B. V. Peterson, G. E. Shewell, H. J. Teskey,
J. R. Vockeroth, and D. M. Wood [eds.], Manual ofNe-
arctic Diptera. Vol. 1. Research Branch, Agriculture.
Canada Monograph No. 27.
GAGNE, R. J. 1981b. A new species of Endaphis
(Diptera: Cecidomyiidae) endoparasitic in aphids in











British Columbia. Proc. Entomol. Soc. Washington
83: 222-224.
GAGNE, R. J. 1989. The Plant-Feeding Gall Midges of
North America. Cornell University Press, Ithaca,
New York. xiii & 355 pp. & 4 pls.
GAGNE, R. J. 1994. The Gall Midges of the Neotropical
Region. Cornell University Press. xv & 352 pp.
GAGNE, R. J. AND F. D. BENNETT. 1993. Two new species
of Lestodiplosini (Diptera: Cecidomyiidae) preying
on Homoptera and Thysanoptera in southern Flor-
ida. Florida Entomol. 76: 341-348.
GAGNE, R. J. AND J. T. LILL. 1999. A new Nearctic spe-
cies of Lestodiplosis (Diptera: Cecidomyiidae) prey-
ing on an oak leaf tier, Psilocorsis quercicella
(Lepidoptera: Oecophoridae). Proc. Entomol. Soc.
Washington 101: 332-336.
HARRIS, K. M. 1966. Gall midge genera of economic impor-
tance (Diptera, Cecidomyiidae). Part 1: Introduction
and subfamily Cecidomyiinae; supertribe Cecidomyi-
idi. Trans.Royal Entomol. Soc. London 118: 313-358.
HARRIS, K. M. 1973. Aphidophagous Cecidomyiidae
(Diptera): taxonomy, biology and assessments of
field populations. Bull. Entomol. Res. 63: 305-325.
KASHYAP, V. 1989. A new species of Lestodiplosis Kief-
fer (Cecidomyiidae: Diptera) from India. Cecidologia
Indica 10: 119-126.
MCALPINE, J. F., B. V. PETERSON, G. E. SHEWELL, H. J.
TESKEY, J. R. VOCKEROTH, AND D. M. WOOD [eds.].
1981. Manual of Nearctic Diptera. Vol. 1. Research
Branch, Agriculture Canada, Monograph 27. vi +
674 pp.


March 2008


MEAD, F. AND J. E. PENA. 1991. Avocado Lace Bug,
Pseudacysta perseae (Hemiptera: Tingidae). Florida
Department of Agriculture and Consumer Services,
Division of Plant Industry Entomology Circular No.
346: 1-4.
MEDINA-GAUD, S., A. E. SEGARRA-CARMONA AND R. A.
FRANQUI. 1991. The avocado lacewing bug, Pseuda-
cysta perseae (Heidemann) (Hemiptera: Tingidae). J.
Agriculture Univ. Puerto Rico 75: 185-188.
MORALES, L. 2005. La chinche de encaje del agua-
catero: Pseudacysta perseae (Heid.) (Heteroptera:
Tingidae). Bioecologia y lucha biological en las
condiciones de Cuba. Universidad Central Martha
Abreu de las Villas. Fac. Ciencias Agropecuaria
Santa Clara, Cuba. Thesis. Unpublished 2005.
66 pp.
PENA, J. E., S. SUNDHARI, A. HUNSBERGER, R. DUNCAN
AND B. SCHAFFER. 1998. Monitoring, damage, natu-
ral enemies and control of avocado lace bug, Pseuda-
cysta perseae (Hemiptera: Tingidae). Proc. Florida
State Hort. Soc. 111: 330-334.
SANDOVAL, M. F. 2004. Presencia de Pseudacysta per-
seae (Heid.) (Insecta: Hemiptera: Tingidae) en Vene-
zuela. P. 54 In Resumenes V Seminario Cientifico
Int. Sanidad Vegetal, Mayo 24-28. La Habana, Cuba.
TANG, Y. Q., R. K. YOKOMI, AND R. J. GAGNE. 1994. Life
history and description of Endaphis maculans (Bar-
nes) (new combination) (Diptera: Cecidomyiidae), an
endoparasitoid of aphids in Florida and the Carib-
bean Basin. Ann. Entomol. Soc. America 87: 523-
531.


Florida Entomologist 91(1)







Brailovsky & Cervantes: New Species of Acroleucus


TWO NEW SPECIES AND DISTRIBUTION RECORDS
OF THE GENUS ACROLEUCUS IN MEXICO
(HEMIPTERA: HETEROPTERA: LYGAEIDAE: LYGAEINAE)

HARRY BRAILOVSKY1 AND LUIS CERVANTES2
1Departamento de Zoologia, Instituto de Biologia, Universidad Nacional Aut6noma de M6xico,
Apdo Postal 70153, M6xico D.F., 04510

2Departamento de Entomologia, Instituto de Ecologia, Jalapa, Veracruz, M6xico

ABSTRACT

The genus Acroleucus Stal from M6xico is revised. Two new species A. calvatus andA. tensus
are described and illustrated. New distribution records are presented, as well as comments
on the host plants for some of the species. A revised key to Mexican species is included.

Key Words: Heteroptera, Lygaeidae, Lygaeinae, Acroleucus, new species, Mexico

RESUME

Se revisa el g6neroAcroleucus Stal para M6xico. Dos nuevas especies,A. calvatus yA. tensus,
son descritas e ilustradas. Nuevos datos de distribuci6n son presentados asi como comenta-
rios sobre las plants hospederas para algunas de sus species. Se incluye una clave para re-
conocer las species mexicanas.


Translation provided by the authors.


The genus Acroleucus Stal, 1874, belonging to
the subfamily Lygaeinae (Heteroptera: Lygaei-
dae), contains 40 species (Brailovsky 1977, 1980,
1984; Brailovsky & Barrera 1984; Slater 1992). It
is a Neotropical genus ranging from Mexico to Ar-
gentina, and is characterized by having the callus
of the anterior pronotal lobe interrupted by longi-
tudinal depressions flanking a distinct median ca-
rina. In Mexico 5 species have been recorded. In
this paper we add 2 new species, include a synop-
tic treatment for previously known taxa, and pro-
vide new distribution and host plants records for
some species.
Habitat.-Very little is known about the habi-
tat requirements of the species of Acroleucus.
Some species are collected on the foliage of
Solanum nigrum L., and Solanum nudum H. B.
M. (Solanaceae), on Ipomoea sp. (Convolvu-
laceae), and Camellias (Theaceae), while others
are associated with Tillandsia dasyliriifolia
Baker, Tillandsia violacea (Baker), Tillandsia
oaxacana L. B. Sm., and Hechtia podantha Mez
(Bromeliaceae).
All measurements are given in mm. Reposito-
ries for specimens and abbreviations given in the
text are as follows: Colecci6n Entomol6gica del In-
stituto de Biologia, Universidad Nacional Au-
tonoma de Mexico, Mexico, D.F. (UNAM), Colec-
ci6n Entomol6gica del Instituto de Ecologia A.C.,
Jalapa, Veracruz (IEXA), and Texas A&M Univer-
sity, Collage Station, TX (TAMU).


Acroleucus brevicollis (Stal)

Lygaeus brevicollis Stal 1862: 311

This species is distinguished from other mem-
bers ofAcroleucus by a combination of the follow-
ing characters: coxae yellow with basal third
brownish hazel, trochanters and bucculae yellow,
head dorsally and antennal segment IV black to
reddish brown, hemelytral membrane dark
brown with apical margin widely hyaline, and
pronotum dark brown with anterior, lateral, and
posterior margin widely yellowish orange.
Distribution.-Recorded from Mexico, San Sal-
vador, Costa Rica, and Panama. Mexico: Chiapas:
La Trinitaria, Comitan, Ocozocoautla and Ixhua-
tan. Estado de Mexico: Real de Arriba (Temas-
caltepec), and Malinalco. Morelos: Cuernavaca.
Nuevo Le6n: Chipinque. Veracruz: Orizaba
(Brailovsky 1977, 1980).
New Records.-Mexico: 1 male, 1 female:
Hidalgo, Hwy 105, 2.4 mi N Tlanchinol, Aug 1982,
C. W. O'Brien and G. Wibmer. 1 female: Oaxaca,
Valle Nacional, Rancho Grande, 900 m, 13 Mar
1989, A. Cadena and L. Cervantes. 1 male: Oax-
aca, km 58 Tuxtepec-Oaxaca, 28 May 1987, L.
Cervantes. 1 female: Puebla, Xicotepec de Juarez,
13 Jul 1980, H. Brailovsky. 1 female: San Luis Po-
tosi, Tamazunchale, 10 Apr 1980, H. Brailovsky. 1
female: Tamaulipas, Gomez Farias, Joya de
Manantiales, 13 Mar 2002, I. Pacheco, A.







Florida Entomologist 91(1)


Sanchez, and L. Cervantes. 1 male, 1 female: Ver-
acruz, Fortin de Las Flores (Estaci6n de Microon-
das), 10 Aug 1980, E. Barrera. 2 males, 1 female:
Veracruz, Jalapa, 22 May 1982, E. Aranda. All the
specimens deposited in UNAM.
Host Plants.-Collected on Solanum nigrum L.
(Solanaceae), Ipomoea sp., (Convolvulaceae), and
Camellias (Theaceae).

Acroleucus bromelicola Brailovsky

Acroleucus bromelicola Brailovsky 1977: 124-126
(Figs. 1, 3)

This species is recognized by having the coxae,
trochanters, basal third of femora, head dorsally,
and bucculae yellow, antennal segment IV dark
brown, and hemelytral membrane dark brown
with hyaline apex digitiform, extending toward
the center of the membrane. Genital capsule. Cir-
cular in cross section; inner space with lateral
arms subtruncated; space between arms with
deep "V" concavity (Fig. 1). Paramere. Shaft ro-
bust; posterior projection broad, hemispheric; an-
terior projection elongate, slender; spur apically
acute, weakly directed upward (Fig. 3).
Distribution.-Only known from Mexico. Mex-
ico: Puebla: Xicotepec de Juarez and Tehuacan; and
San Luis Potosi: Tamazunchale (Brailovsky 1977,
1980). The records given by Brailovsky (1977,
1980) from Sonora (Alamos and Nogales) are erro-
neous and belong to the new speciesA. tensus.
New Records.-Mexico: 1 male, 1 female: Oax-
aca, Ayautla, 700 m, 17 Mar 1989, A. Cadena and
Cervantes. 2 females: km 55 Oaxaca-Tehuante-
pec, 1950 m, 5 Sep 1979, E. Barrera. 3 males, 3 fe-
males: Puebla, Cuetzalan, Santiago Yacuncual-
pan (Cuautanapaluyan), 940 m, 19 May 1995, E.
Barrera and G. Ortega-Le6n. 2 females: km 6.5
Breca-Huazor, nr Tilazo, 26 Apr 1998, E. Barrera
and C. Mayorga. 1 female: Veracruz, Municipio
Buena Vista, Iztaczoquitlan, 1000 m, 28 Jul 2000,
E. Barrera and A. Ibarra. 2 females: Tamaulipas,
Gomez Farias, Camino del Ejido El Azteca, 18
Sept 2003, Q. Santiago and Luis Cervantes. 1 fe-
male: Tamaulipas, G6mez Farias, El Cielo, 14
April 2003, I. Pacheco and Luis Cervantes. 1 fe-
male: Veracruz, km 13 Coatepec-Huatusco, 600
m, 12 Mar 1989, A. Cadena and L. Cervantes. The
specimens are deposited in IEXA and UNAM.
Host Plant.-Collected on Tillandsia dasylirii-
folia Baker (Bromeliaceae).

Acroleucus calvatus Brailovsky and Cervantes
NEW SPECIES (Fig. 6)

Types.-Holotype female: Mexico: Chiapas, 31
mi SE Comitan, 18-19 Jun 1965, H. R. Burke,
J.R. Meyer, and J. C. Schaffner (TAMU).
Paratypes: 2 females: same data as holotype
(TAMU, UNAM).


Description.-Female holotypee). Dorsal color-
ation: Head yellowish hazel except for 2 short red-
dish brown irregular transverse marks restricted
to the interocellar space; antennal segments I to
IV reddish brown; pronotum yellowish orange
with 2 large, irregular pale to dark brown spots at
posterior lobe and transverse line; scutellum red-
dish brown to dark brown, middle third of apical
half yellowish orange; clavus dark brown, claval
commissure yellow; corium dark brown, costal
margin and apical angle yellow; hemelytral mem-
brane ocher, and apical margin widely hyaline.
Ventral coloration: Head including the bucculae
pale yellowish orange; juga and rostral segments
I, III and IV dark orange hazel; rostral segment II
yellowish hazel; propleura shiny orange with pale
brown spot near middle third; prosternum yellow-
ish white; mesopleura pale to dark brown, with
anterior margin, posterior margin and acetabu-
lum dark to pale yellowish white; mesosternum
dark yellowish white, and transverse line pale to
dark brown; metapleura pale to dark brown,
tinged with orange hazel marks, and anterior
margin, posterior margin, and acetabulum pale to
dark yellowish white; metasternum reddish or-
ange; ostiolar peritreme yellowish white; coxae,
and trochanters yellow; femora pale brown,
tinged with orange hazel, and basally yellow; tib-
iae and tarsi reddish brown; abdominal sterna
and genital plates pale brown, except middle
third of sterna, posterior margin of sterna VI and
VII, and pleural margins yellow.
Structure.-Rostrum reaching posterior mar-
gin of abdominal sternite III; rostral segment I
reaching anterior margin of prosternum.
Variation.-(1) Fore femur entirely pale
brown, tinged with orange hazel. (2) Mesoster-
num brown, anterior and posterior margins yel-
low, and transverse line black. (3) Metasternum
brown, with posterior margin yellow. (4) Posterior
margin of abdominal sterna III to V yellow.
Male-Unknown.
Measurements (n = 1).-Female. Head length
1.05; width across eyes 1.60; interocular space
0.95. Length of antennal segments: I, 0.45; II,
1.25; III, 1.15; IV, 1.40. Pronotum: Total length
1.25; maximum width across anterior lobe 1.50;
maximum width across posterior lobe 2.50. Scutel-
lar length 1.00; width 1.27. Total body length 8.18.
Discussion.-This new species is related to A.
orinocoensis Brailovsky, in having the coxae and
trochanters yellow, hemelytral membrane ocher,
with apical margin widely hyaline, head dorsally
yellow with reddish brown to pale brown marks,
restricted to the interocellar space and transverse
line, and antennal segment IV black to reddish
brown. In A. orinocoensis the pronotum, clavus,
corium, prothorax, and metathorax are entirely
yellow and the antenniferous tubercle dark brown
to black. In A. calvatus the pronotum, clavus, co-
rium, prothorax, and mesothorax are not entirely


March 2008







Brailovsky & Cervantes: New Species of Acroleucus


yellow, and the antenniferous tubercles are yel-
lowish orange.
Etymology.-From the Latin, calvata, meaning
smooth.

Acroleucus nexus Brailovsky and Barrera
Acroleucus nexus Brailovsky and Barrera 1984: 96-97
Easy to recognize by having the coxae yellow
with basal third orange hazel, trochanters yellow,
bucculae black, hemelytral membrane dark
brown with apical border narrowly hyaline and
difficult to see, pronotum, scutellum, and clavus
entirely dark brown, and head dorsally shiny or-
ange with tylus, juga, and distinct median longi-
tudinal stripe black.
Distribution.-Only known from Mexico. Mex-
ico: Morelos, Cuernavaca (Brailovsky and Bar-
rera 1984).
New Records.-1 male, 1 female: Oaxaca, Ixte-
peji, Pefia Prieta, Mar 2006, A. Franco (UNAM).
Host Plant-Collected on Tillandsia violacea
(Baker) and Tillandsia oaxacana L. B. Sm. (Bro-
meliaceae).

Acroleucus signaticollis Stil
Acroleucus signaticollis Stal 1874: 114
Clearly distinguished by the coxae, trochant-
ers, and bucculae yellow, hemelytral membrane


brown to ocher with contrasting dark brown veins,
and apical margin widely hyaline; head dorsally
yellowish orange with distinct black median lon-
gitudinal stripe, antennal segment IV black to
reddish brown, and pronotum, corium, femora,
and tibiae predominantly yellow to pale brown.
Distribution.-Recorded from Mexico, Hondu-
ras, Costa Rica, Panama, Colombia, British Gui-
ana. Mexico: San Luis Potosi: road Tamazun-
chale-Ciudad Valles (Brailovsky 1980).

Acroleucus tensus Brailovsky and Cervantes
NEW SPECIES (Figs. 2, 4-5, 7-8)

Types.-Holotype male: Mexico: Oaxaca, km.
56, road Oaxaca-San Migue Sola de Vega, 1 Jul
1990, E. Barrera and A. Cadena (UNAM).
Paratypes: 9 males, 7 females: same data as holo-
type (UNAM). 1 female: Oaxaca, Municipio Tlaco-
lula, San Juan Guelavia, 1658'00"N, 9632'57"W,
1600 m, 31 Dec 2004, H. Brailovsky and E. Bar-
rera (UNAM). 16 males, 11 females: Oaxaca, 17
km SE de Huajuapan de Le6n, 29 Jun 1996, E.
Barrera and H. Brailovsky (UNAM). 2 males, 2 fe-
males: Oaxaca, Pochutla-Pluma Hidalgo, 3 Jun
1987, E. Barrera, F. Arias, and L. Cervantes.
(UNAM). 1 female: Oaxaca, 2 km SW, El Cama-
r6n, 12 Jul 2000, E. Barrera, A. Ibarra, and C.
Mayorga (UNAM). 2 males, 2 females: Guerrero,
Atoyac-Nueva Delhi, Rio Santiago, 21 Apr 1988,


Figs. 1-5. Acroleucus spp. 1-2. Male genital capsule in dorsal view. 1. A. bromelicola Brailovsky. 2. A. tensus
Brailovsky and Cervantes. Figs. 3-4. Paramere. 3.A. bromelicola Brailovsky. 4.A. tensus Brailovsky and Cervantes.
5. Spennatheca ofA. tensus Brailovsky and Cervantes.







Florida Entomologist 91(1)


/


Fig. 7. Dorsal view of Acroleucus tensus Brailovsky
and Cervantes.


Fig. 6. Dorsal view ofAcroleucus caluatus Brailovsky
and Cervantes.

A. Cadena, M. Garcia, and L. Cervantes (UNAM).
3 males, 1 female: Guerrero, Zihuaquio, 15 Apr
1988, L. Cervantes, M. Garcia, and A. Cadena
(UNAM). 1 male: Michoacan, km 93 Uruapan-
Playa Azul, Finca El Manguito, 1300 m, 26 May
1988, L. Cervantes and A. Cadena (UNAM). 1
male: km 90 Patzcuaro-La Huacana, 1400 m, 1
Jun 1988, L.Cervantes and A. Cadena (UNAM).
11 males, 12 females: Hidalgo, 5 km NE Pachuca,
24 Feb 1990, E. Barrera and H. Brailovsky. Col-
lected in Hechtia podantha Mez (Bromeliaceae)
(UNAM). 1 male, 2 females: Hidalgo, San Miguel
Regla, Hueyapan, and Pefia del Aire, 24 Feb 1990,
7-8 Jun 1990, H. Brailovsky and E. Barrera
(UNAM). 1 male, 1 female: Hidalgo, Zimapan, 26
Mar 1997, H. Brailovsky (UNAM). 1 male: Quere-
taro, Jalpan de Amoles, 1180 m, 2111'69"N,
99037'84"W, 5 Nov 1997, E. Barrera and G. Or-
tega-Le6n (UNAM). 3 males, 4 females: Guana-
juato, Yuriria, 13 Mar 1997, E. Barrera and H.
Brailovsky (UNAM). 2 females: Puebla, Coscat-
lan, 1050 m, 5 Jul 1979, 8 Sep 1979, E. Barrera
and G. Ortega-Le6n (UNAM). 1 female: Puebla, 6
km NW Teontepec, 1900 m, 14 Jul 1999, H.
Brailovsky and E. Barrera (UNAM). 2 females:
Puebla, 2.5 km SW de Zapotitlan, 1490 m, 13 Jul


1999, E. Barrera and H. Brailovsky (UNAM). 2
males: Puebla, 2 km N Calipan, 18 Mar 1993, E.
Barrera (UNAM). 2 males: Puebla, San Juan
Raya, 19 Jan 1992, H. Brailovsky, E. Barrera, C.
Mayorga, and G. Ortega-Le6n (UNAM). 1 female:
Puebla, Atexcoco, 12 Mar 1994, E. Barrera and C.
Mayorga (UNAM). 1 male, 1 female: Puebla, Ax-
usco-Petlanco, 5 Nov 1988, E. Barrera, R. Barba,
and L.Cervantes (UNAM). 1 female: Chiapas,
Reserva El Ocote, 29 Apr-3 May 1993, E. Barrera
(UNAM). 1 female: km 6 Motozintla-Siltepoc, 8
Jul 1988, A. Cadena (UNAM). 3 males, 5 females:
Tamaulipas, Jaumave, el Salto, 1111 m,
23021'23"N, 99030'54"W, 12 May 2007, H.
Brailovsky, E. Barrera and L. Cervantes (IEXA,
UNAM). 1 male: Tamaulipas, Ciudad Victoria,
Balc6n de Moctezuima, 1000 m, 23035'08"N,
99011'10"W, 13 May 2007, H. Brailovsky, E. Bar-
rera and L. Cervantes (UNAM).
Description.-Male holotypee). Dorsal colora-
tion: Head pale yellowish orange, except black
apex of tylus, and juga; antennal segments I to IV
dark brown; pronotum dark brown with narrow
brownish ocher anterolateral margins; scutellum
and clavus brown; corium brown with costal mar-
gin yellow; hemelytral membrane pale brown, api-


March 2008







Brailovsky & Cervantes: New Species of Acroleucus


imm



















8
Fig. 8. Dorsal view of Acroleucus tensus Brailovsky
and Cervantes.


cal border narrowly hyaline (difficult to see). Ven-
tral coloration: Head yellow except brown to black
bucculae; rostral segments I to IV brownish hazel;
thorax brown; mesosternum transversely yellow-
ish hazel; ostiolar peritreme dark yellow tinged
with pale brown marks; coxae yellow with basal
third orange hazel; trochanters yellow; femora
brown, basal third yellow; tibiae pale brown; tarsi
brown, except each basal segment with anterior
third dark yellow; abdominal sterna pale brown,
pleural margins yellow; pygophore pale brown.
Structure.-Rostrum reaching anterior mar-
gin of abdominal sternite III; rostral segment I
extending to anterior border of prosternum. Gen-
ital capsule: circular in cross section; inner space
with lateral arms wide opened and robust; space
between arms with "V" concavity slightly pro-
nounced (Fig. 2). Paramere: shaft robust; poste-
rior projection well developed, thick, subconical;
anterior projection elongate, slender; spur api-
cally acute, clearly directed upward (Fig. 4).
Female.-Color and habitus similar to male
holotype. Spermatheca: bulb moderately broad;
tube extremely elongate, slender and complexly
coiled (Fig. 5).
Variation.-(1) Pale to dark brown color of
pronotal disk, scutellum, clavus and corium even-


tually black. (2) Head dorsally pale yellow, except
black apex of tylus and juga. (3) Humeral angles
yellow. (4) Ostiolar peritreme yellowish white to
pale brown, suffused or not with yellow marks.
(5) Inner border of clavus, and claval commissure
yellow to brown.
Measurements (n = 10).-Male (female). Head
length 0.63 (0.71); width across eyes 0.92 (1.01);
interocular space 0.60 (0.65). Length of antenna
segments: I, 0.22 (0.25); II, 0.62 (0.68); III, 0.54
(0.59); IV 0.78, (0.83). Pronotum: Total length
0.68 (0.72); maximum width across anterior lobe
0.83 (0.93); maximum width across posterior lobe
1.46 (1.64). Scutellar length 0.57 (0.62); width
0.77 (0.88). Total body length 4.62 (5.17).
Discussion.-This new species is related to A.
nexus Brailovsky, in having the bucculae, and
scutellum pale brown to black, the hemelytral
membrane pale to dark brown with apical border
narrowly hyaline and difficult to see, coxae yellow
with basal third orange hazel, and trochanters
yellow. In A. nexus the head dorsally is shiny or-
ange, except tylus, juga, and distinct black me-
dian longitudinal stripe, femora entirely reddish
orange, rostrum reaching posterior margin of ab-
dominal sternite III, corium black with costal
margin narrowly yellow, and mesosternum with
transverse line shiny brown to black. InA. tensus
the head dorsally is yellowish orange except black
apex of tylus and juga, femora brown with the
basal third yellow, rostrum reaching anterior
margin of abdominal sternite III, corium brown
with costal margin widely yellow, and mesoster-
non with transverse line yellowish hazel.
Etymology.-From the Latin tensus, referring
to the narrow general shape of the species.

Acroleucus tullus (Stal)

Lygaeus tullus Stal 1862: 311

This species is separated by having the coxae
yellow with basal third brownish hazel, trochanters
and bucculae yellow, head dorsally and antenna
segment IV black to dark brown, hemelytral mem-
brane dark brown with apical margin widely hya-
line, and pronotal disk dark brown with anterior
and lateral margins widely yellowish orange, and
posterior margin black or very narrowly yellowish
orange usually restricted to the humeral angles.
Distribution.-Widely distributed through Mex-
ico, Guatemala, Costa Rica, Panama and Vene-
zuela. Mexico: Chiapas: Ocozocoautla e Ixhuatan.
Guerrero: Chilpancingo. Veracruz, Cordoba, Jal-
apa, and Orizaba.
New Records.-Mexico: 1 male: Jalisco, 12 mi S
of Mazamitla, 5 Dec 1948. 2 males, 2 females:
Oaxaca, km 41 Puerto Escondido-Sola de Vega,
855 m, 4 Jul 1990, E. Barrera and A. Cadena. 3
males: Oaxaca, Tlacolula, km 17 Tlacolula-El
Carrizal, 2240 m, 1703'52"N, 9624'67"W, 4 Sep











2004, L. Cervantes y J. Calonico. 1 male: Oaxaca,
km 111 Oaxaca-Puerto Escondido, 1443 m,
16026'05"N, 97001'58"W, 1 Dec 2006, E. Barrera. 1
male: Oaxaca, San Pedro Yolox, Sta. Cruz Teoeto-
tutla, 1167 m, 17044'25"N, 96033'48"W, 1 Sep
2004, L. Cervantes and J. Calonico. 1 male, 3 fe-
males: Oaxaca, Portillo del Rayo, 18 Oct 1985, 30
May 1987, E. Barrera. 1 male: Oaxaca, San Mateo


March 2008


Yetla, 21 Sep 1982, A. Ibarra. 1 male: Oaxaca, km
176 Puerto Angel-Oaxaca, 18 Apr 1983, A. Ibarra.
1 female: Guerrero, Ixcateopan, km 4.5 road to
Amealco, 1480 m, 13 Sept 2006, L. Cervantes and
L.Lozada. All the specimens deposited in UNAM
Host Plants.-Collected on the leaves of
Solanum nigrum L. and Solanum nudum H. B.
M. (Solanaceae).


REVISED KEY TO MEXICAN SPECIES OF ACROLEUCUS

1. Hyaline apex of hemelytral membrane with digitiform extension toward center of membrane
................................................................. A. bromelicola Brailovsky

1'. Hyaline apex of hemelytral membrane not extended toward center of membrane, restricted to apical margin.
..................................................................................2

2. Bucculae black to pale brown; hyaline apex of hemelytral membrane narrow, difficult to see .............. 3

2'. Bucculae yellow; apical margin of hemelytral membrane widely hyaline .............................. 4

3. Head dorsally shiny orange, except tylus, juga, and distinct black medial longitudinal stripe; basal third of fem-
ora black to dark brown; tarsi brown to black ........................ A. nexus Brailovsky & Barrera

3'. Head dorsally yellowish orange, except black apex and juga; basal third of femora yellow; tarsi brown except
each basal segment with anterior third yellow ...... A. tensus Brailovsky & Cervantes NEW SPECIES

4. Head dorsally yellowish orange, suffused with pale brown marks ................... ................ 5

4'. H ead dorsally black to dark brown ............................................................. 6

5. Veins of hemelytral membrane black, contrasting with dark brown surrounding areas
.......................................................................A sig naticollis Stil

5'. Veins of hemelytral membrane concolorous with surrounded areas
......................................... A. caluatus Brailovsky & Cervantes NEW SPECIES

6. Posterior pronotal margin widely yellowish orange .................. .............. A. brevicollis (Stal)

6'. Posterior pronotal margin black or very narrowly yellowish orange ...................... .A. tullus (Stal)


ACKNOWLEDGMENTS

We are much indebted to Dr. Joseph C. Schaffner
(Texas A, & M. University, College Station) for kindly
providing material. We thank Ernesto Barrera for com-
ments on the manuscript, and Albino Luna for the prep-
aration of dorsal view illustrations (each one at the
Institute de Biologia, Universidad Nacional Aut6noma
de M6xico). Comments on the manuscript from anony-
mous reviewers are greatly appreciated. Support for the
research reported in this paper was provided by UNAM-
DGAPA, IN-223503-3.

LITERATURE CITED

BRAILOVSKY, H. 1977. Contribuci6n al studio de los
Hemiptera-Heteroptera de M6xico. XIII. Revision
del g6nero Acroleucus Stal (Lygaeidae-Lygaeinae)
con descripci6n de una nueva especie. Anales Inst.
Biol. Univ. Nal. Aut6n. M6xico, Ser. Zool. 48: 123-128.


BRAILOVSKY, H. 1980. Revision del g6nero Acroleucus
Stal (Hemiptera-Heteroptera-Lygaeidae-Lygaeinae).
Folia Entomol6gica Mexicana 44: 39-120.
BRAILOVSKY, H. 1984. Nuevas adiciones al g6nero Acro-
leucus Stal (Hemiptera-Heteroptera-Lygaeidae-Lyg-
aeinae). Anales Inst. Biol. Univ. Nal. Aut6n. M6xico
(1982), Ser. Zool. 54: 35-52.
BRAILOVSKY, H., AND E. BARRERA. 1984. Cinco species
nuevas, nuevos datos distribucionales y notas bi-
ol6gicas acerca de Lygaeinae americanos (Lyga-
eidae: Hemiptera: Heteroptera). Anales Inst. Biol.
Univ. Nal. Aut6n. M6xico, Ser. Zool. 55: 95-110.
SLATER, ALEX. 1992. A genus level revision of Western
Hemisphere Lygaeinae (Heteroptera: Lygaeidae)
with keys to species. The University of Kansas, Sci-
ence Bulletin 55: 1-56.
STAL, C. 1862. Hemiptera mexicana enumeravit
speciesque novas descripsit. Stettiner Entomol. Zei-
tung. 23: 289-325.
STAL, C. 1874. Enumeratio Hemipterorum. Part 4.
Kongl. Svenska Vetensk-Akad. Handl. 12 (1): 1-186.


Florida Entomologist 91(1)







Virla et al.: Bionomics of the Sharpshooter Oncometopia tucumana


BIONOMICS OF ONCOMETOPIA TUCUMANA (HEMIPTERA:
CICADELLIDAE), A SHARPSHOOTER FROM ARGENTINA, WITH NOTES
ON ITS DISTRIBUTION, HOST PLANTS, AND EGG PARASITOIDS

EDUARDO G. VIRLA1, GUILLERMO A. LOGARZO2, SUSANA L. PARADELL3 AND SERGUEI V. TRIAPITSYN4
'PROIMI-Biotecnologia, Divisi6n de Control Biol6gico, Avenida Belgrano y Pasaje Caseros,
T4001 MVB, San Miguel de Tucuman, Tucuman, Argentina
E-mail: evirla@hotmail.com

2USDA-ARS, South American Biological Control Laboratory, Bolivar 1559 (1686),
Hurlingham, Buenos Aires, Argentina
E-mail: glogarzo@speedy.com.ar

3Facultad de Ciencias Naturales y Museo de La Plata, Universidad Nacional de La Plata,
Paseo del Bosque sin nmmero, CP 1900, La Plata, Buenos Aires, Argentina
E-mail: paradell@museo.fcnym.unlp.edu.ar

4Entomology Research Museum, Department of Entomology, University of California, Riverside, CA 92521, USA
E-mail: serguei.triapitsyn@ucr.edu

ABSTRACT

Bionomics of the proconiine sharpshooter Oncometopia tucumana Schr6der (Hemiptera: Ci-
cadellidae) from northern Argentina is reported. Leafhoppers were monitored during the en-
tire season in a citrus orchard in Horco Molle, Tucuman Province, and also sampled in Jujuy
and Salta Provinces. The sharpshooters were found from spring to late fall; they overwinter
as adults and females do not lay eggs from Apr to Oct. Oncometopia tucumana is polypha-
gous, 12 plants in 11 families were recorded as its hosts for the first time. Egg masses of
0. tucumana were attacked by 3 parasitoid species, Gonatocerus annulicornis (Ogloblin),
G. metanotalis (Ogloblin), and G. tuberculifemur (Ogloblin) (Hymenoptera: Mymaridae),
that collectively produced egg mortality close to 60%. Gonatocerus annulicornis was the
main egg parasitoid, emerging from nearly 80% of the parasitized eggs.

Key Words: Proconiini, Oncometopia, seasonal occurrence, Mymaridae, Gonatocerus

RESUME

En este trabajo se informan aspects biol6gicos del proconino Oncometopia tucumana
Schr6der (Hemiptera: Cicadellidae) en el norte de Argentina. Las chicharritas fueron moni-
toreadas durante todo un aio en un cultivo de citrus en Horco Molle, provincia de Tucuman,
asi como en las provincias de Jujuy y Salta. Estas chicharritas fueron encontradas desde la
primavera hasta finales del otofio, pasando el invierno como adults y sus hembras no depo-
sitan huevos durante dicho period, entire abril y octubre. Oncometopia tucumana es poli-
faga y habiendo sido registrada en 12 plants hospedadoras, pertenecientes a 11 families.
Las posturas de 0. tucumana son atacadas por tres species de parasitoides, Gonatocerus
annulicornis (Ogloblin), G. metanotalis (Ogloblin) y G. tuberculifemur (Ogloblin) (Hymenop-
tera: Mymaridae), quienes en conjunto produce una mortalidad de huevos cercana al 60%.
Gonatocerus annulicornis fue el principal parasitoide o6fago, emergiendo de aproximada-
mente un 80% de los huevos parasitizados.

Translation provided by the authors.


The tribes Proconiini and Cicadellini, com- tor of the bacterium Xylella fastidiosa that causes
only referred to as sharpshooters (Hemiptera: Pierce's disease of grapes and phony peach dis-
Cicadellidae: Cicadellinae), represent the largest ease in the USA and Mexico. In California, USA,
group of xylem-feeding leafhoppers and include production of wine and table grapes is under
most of the known vectors of xylem-born phyto- threat due to the efficiency of the GWSS in vector-
pathogenic organisms (Rakitov & Dietrich 2001). ing this pathogen (Blua et al. 1999).
The glassy-winged sharpshooter (GWSS), Homa- Oncometopia Stal is widely distributed in the
lodisca vitripennis (Germar), is a well-known vec- New World, from northern USA to Argentina, and







Florida Entomologist 91(1)


is the most largest genus of the Proconiini, or pro-
coniine sharpshooters. Some species are of signif-
icant economic importance, e.g., 0. orbona (Fabr-
icius) and 0. nigricans (Walker), are vectors ofX.
fastidiosa, and Oncometopia facialis (Signoret) is
involved in X. fastidiosa transmission in citrus
and coffee in Brazil that causes citrus variegated
chlorosis (Lopes 1999; Yamamoto et al. 2002).
Two species of Oncometopia occur in Argentina:
0. facialis in Misiones Province (Remes Lenicov
et al. 1999) and 0. tucumana Schroder in north-
ern Argentina (Schroder 1959; Young 1968), with
a recent record from Horco Molle, Tucuman Prov-
ince (Takiya & Dmitriev 2004-2006).
Since Dec 2000, the USDA-ARS South Ameri-
can Biological Control Laboratory, Hurlingham,
Buenos Aires, Argentina (SABCL) has been con-
ducting a survey of egg parasitoids of the proconi-
ine sharpshooters in South America for the neo-
classical biological control program against the H.
vitripennis in California. This approach is based
on the "new association" strategy (Pimentel 1963,
1991; Hokkanen & Pimentel 1989) that involves
selection of natural enemies of the species closely
related to the target pest, with which the natural
enemies have not had a previous association.
Short distances in the taxonomic proximity be-
tween the host and the target species increase the
probability of success (Van Driesche & Bellows
1996). Studies in South America on the biology
and natural enemies of the proconiine sharp-
shooter genera closely related to Homalodisca
Stal are of particular interest. This study is fo-
cused on 0. tucumana due to the close relation-
ship between the genera Oncometopia and Homa-
lodisca (Young 1968). We investigated seasonal oc-
currence, host plants (for feeding and oviposition),
oviposition substrates, and egg parasitoid com-
plex of 0. tucumana in cultivated and surround-
ing wild areas in Tucuman Province of Argentina.

MATERIAL AND METHODS

Seasonal Abundance in a Citrus Orchard

Temporal occurrence and abundance of O. tucu-
mana and its egg parasitoids were estimated in a
4-ha abandoned 40-years-old lemon orchard, sur-
rounded by wild vegetation located in Horco Molle,
Tucuman Province in the Yunga's rainforest
(2646'50.1"S, 6519'38.3"W; elevation: 703 m; an-
nual precipitation: 1250 mm; summer mean tem-
perature (Jan): 23.80C, winter mean temperature
(Jul): 11.30C). The sampling was conducted weekly
from mid Sep 2003 to late Jun 2004, and consisting
in searching at random during 45 min for the egg
masses on leaves and stems. Fifteen trees were
checked during each sampling session. In addi-
tion, shrubbery plants surrounding the lemon
trees were checked. Nymphs and adults were sam-
pled by sweeping with a standard entomological


net on the same plants where the visual search for
eggs was conducted. The collected sharpshooters
were taken to the laboratory, sexed, and some of
them preserved as voucher specimens.

Distribution and Host Plants

A non-systematic search for 0. tucumana and
its egg parasitoids was made on the wild plants
and 2 agricultural crops in 58 sites between
26022' to 2758'S and 64033' to 65044'W, in the fol-
lowing 3 areas: southern Andean Yunga's region,
Chaco region, and the ecotone between both re-
gions in Tucuman Province. In addition, the 2
main entomological collections in Argentina: Mu-
seo de Ciencias Naturales, La Plata, Buenos Aires
(MLPA) and Instituto y Fundaci6n "Miguel Lillo",
San Miguel de Tucuman, Tucuman (IMLA), were
consulted for specimens of this sharpshooter.
Yunga's is a submontane and montane ever-
green forest with altitudes between 500 and 2000
m. This forest is characterized by a great varia-
tion in rainfall; being all tropical, frequently
foggy, and has a low annual range of temperature.
Annual precipitation range of the Yunga's forest
is between 1000 and 2000 mm; the dry season
lasts 2 to 5 months. Chaco is a tropical deciduous
dry forest with annual precipitation ranging from
500 to 900 mm; the dry season lasts 5 to 8
months. Chaco is a wooded region where the av-
erage temperature in the coldest month is greater
than 130C; it is widely disturbed by agricultural
activities.
The survey was conducted between Dec 2002
and Dec 2005. Most samples from crops were col-
lected on citrus (mainly lemon) and a few also on
corn. The wild vegetation was surveyed by search-
ing on the plants that surrounded the crops and
also on the plants growing along roadways. The
plants were sampled for adult sharpshooters by
different methods according to plant size and
structure. Herbs and small shrubs were sampled
by sweeping or by hand-beating over a white plas-
tic tray (30 x 27 x 17 cm) or a sheet (100 x 100 cm).
Medium and large shrubs were sampled by hand-
beating over a tray or a sheet. All plants sampled
for adults were also checked for egg masses.

Egg Parasitoids

Egg masses of 0. tucumana were removed
from the plants and kept separately for parasitoid
emergence in Petri dishes with the bottom lined
with wet tissue paper. Each Petri dish was cov-
ered with plastic food wrap to avoid dehydration
of the eggs and the leaves. Subsequently, nymph
and parasitoid emergence was recorded; the spec-
imens were preserved in 70% ethanol, labeled,
and identified. Egg masses that did not have any
developed embryos or parasitoid pupae were not
considered.


March 2008







Virla et al.: Bionomics of the Sharpshooter Oncometopia tucumana


Voucher Specimens

Insect voucher specimens were deposited in
IMLA and the Entomological Research Museum,
University of California at Riverside, California,
USA. Plant voucher specimens were deposited in
SABCL.

RESULTS
Seasonal Abundance in a Citrus Orchard

Oncometopia tucumana was collected from
spring to late fall (Fig. 1). No adults or nymphs
were found from Jul to mid Oct (winter to spring).
First egg masses were collected at the beginning
of the growing season (Oct). However, first adults
were observed in Nov (middle of spring). Oviposi-
tion occurred from Oct to the end of Mar (spring to
summer); no egg masses were found from Apr
through early Oct (Fig. 1).
The sex ratio of 0. tucumana was male biased
(2.5:1; n = 517). When the sex ratio was calculated
monthly, it was still male biased but the propor-
tion of males started to decrease with time, so
that the sex ratio reached approximately 1:1 dur-
ing the fall (Apr to May) (Fig. 2). Like other proco-
niine sharpshooters, females of 0. tucumana lay
eggs endophytically as a cluster, oriented nearly
parallel to one another, and the egg masses are
coated with brochosomes (Rakitov 2004) (Fig. 4).
In total, 45 egg masses (413 eggs) were col-
lected during the study, with 34 masses found on
the leaves (75.6%) and 11 (24.4%) on the stems.


150 -


120 -


90 -


60 -


All egg masses on the leaves were located in the
abaxial surface, and we never found more than 1
per leaf.

Sharpshooter Distribution and Host Plants
We found 0. tucumana in 10 sites (27.6% of the
sampled sites) in non-disturbed areas of both the
Yunga's rainforest (60%) (Horco Molle, Lules,
Yerba Buena, Los Nogales, Tafi Viejo, and Santa
Lucia), and the ecotone between Yunga's and
Chaco regions (40%) (El Manantial, La Rincon-
ada, Macomitas, and San Miguel de Tucuman).
Oncometopia tucumana was always found in the
Yunga's rainforest, mostly in non-disturbed areas
of the foothills of San Javier Mountains. The egg
masses collected from corn were obtained in sub-
sistence crops surrounded by dense natural vege-
tation. In addition, in IMLA we found 2 male
specimens from Embarcaci6n (Salta Province),
6.ii.1950, collected by Golbach, and 4 female spec-
imens from Aguas Calientes (Jujuy Province),
1.iv.2004, collected by G. Logarzo; both localities
have typical rainforest vegetation and are located
in the ecotone between Yunga's and Chaco region.
The pattern of plant utilization was influenced
by the host plant species. Some plants supported
only adults while others supported both adults
and eggs. Adults of 0. tucumana were collected on
12 host plants from 11 different families (Table 1).
However, most collections were made on 2 plant
species from 2 different families: shrub verbena,
Lantana camera (Verbenaceae) and yellow trum-
pet-flower, Tecoma stans (Bignoniaceae). No eggs


Mi egg masses 6

-4-Adults 5


-4


-3 S
o


Province, Argentina) during 2003 and 2004.







Florida Entomologist 91(1)


Oct Nov Dec Jan Feb Mar Apr May Jun Jul

Fig. 2. Seasonal sex ratio rate of Oncometopia tucu-
mana in an abandoned citrus orchard at Horco Molle
(Tucuman Province, Argentina) during 2003-2004.

were found on those plants. The plants mostly uti-
lized for oviposition were Tucuman cedar, Cedrela
lilloi (Meliaceae), and lemon, Citrus limon (Ruta-
ceae), which account for more than 76% of the col-
lected eggs. Three plants were found as occasional
oviposition hosts, on which the sharpshooter indi-
viduals, however, were never found: guava, Psid-
ium guajava (Myrtaceae), flame berry, Urera car-
acasana (Urticaceae), and Johnson grass, Sor-
ghum halepense (Poaceae). Most of the oviposi-
tional hosts were trees and shrubs (Table 1).
On average, an egg mass contained 9.7 3.6
eggs (range: 2-18). However, the size of the egg
masses varied depending on the host plant. Egg
masses on corn leaves contained more eggs than
those on citrus stems or on glossy privet bush, Li-
gustrum lucidum (Oleaceae), leaves (Table 2). The
host plant also affected the number of egg masses
collapsed or preyed upon (30% on Tucuman cedar
and 14% on Citrus spp.).


Egg Parasitism of 0. tucumana in the Citrus Orchard

In the abandoned lemon orchard, 43 egg
masses with the total of 413 eggs were collected.
Parasitoids were responsible for 40.0% of the total
egg mortality, 8.2% of the eggs were preyed upon
or collapsed, and 51.8% (165 eggs) were not para-
sitized (the host nymphs emerged). Three my-
marid (Hymenoptera: Mymaridae) species were
identified from the 108 parasitoids collected: 86
individuals of Gonatocerus annulicornis (Oglob-
lin) (79.63%), 13 individuals of G. tuberculifemur
(Ogloblin) (12.04%), and 9 individuals of G. met-
anotalis (Ogloblin) (8.33%). All of these were soli-
tary parasitoids. Gonatocerus annulicornis was
the most important in terms of occurrence, abun-
dance, and incidence, occurring from early Nov to
late Feb. Gonatocerus tuberculifemur appeared in
Jan and Feb, while G. metanotalis was only ob-
tained from the egg masses laid during Feb. The
egg masses of 0. tucumana laid during early
spring (Oct) and late summer (Mar) were not par-
asitized (Fig. 3).

Egg Parasitism Relative to 0. tucumana Distribution
and Host Plants

During the survey, the overall percentage of
the parasitized eggs was 61.6% of the 1699 col-
lected eggs. The rate of attack varied according to
the collection site, the host plant, and the part of
the plant used for oviposition, i.e., a leaf or a stem.
The same 3 species of Mymaridae, which were col-
lected in the citrus orchard, were also obtained
throughout the entire surveyed area. Gonatocerus
annulicornis was the most abundant egg parasi-
toid, with 66.7% of the emerged wasps. Interest-
ingly, G. annulicornis was the only egg parasitoid


TABLE 1. HOST PLANTS ON WHICH ADULTS AND/OR EGG MASSES OF ONCOMETOPIA TUCUMANA WERE COLLECTED IN TU-
CUMAN PROVINCE, ARGENTINA.

Adults Egg masses
Plant species (Family) Common name frequency frequency

Lantana camera (Verbenaceae) Shrub Verbena +++
Tecoma stans (Bignoniaceae) Yellow Trumpet-flower +++
Cedrela lilloi (Meliaceae) Tucuman Cedar ++ +++
Citrus limon (Rutaceae) Lemon ++ +++
Diadenopteryx sorbifolia (Sapindaceae) "Ivird Pihu" ++ +
Zea mays (Poaceae) Corn or Maize + +++
Ligustrum lucidum (Oleaceae) Glossy Privet Bush + ++
Ruprechtia laxiflora (Polygonaceae) "Virar6" or "Virari" + +
Bauhinia forficata (Fabaceae) Brazilian Orchid Tree + +
Psidium guajava (Myrtaceae) Guava or "Goyavier" -++
Urera caracasana (Urticaceae) Flame Berry +
Sorghum halepense (Poaceae) Johnson Grass +

(+++) frequently found in 50-80% of the examined plants; (++) scarce, found in 10-49% of the examined plants; (+) rare, found in
less than 10% of the examined plants; (-) never found.


March 2008







Virla et al.: Bionomics of the Sharpshooter Oncometopia tucumana


TABLE 2. NUMBER OF EGGS MASSES AND EGG OF ONCOMETOPIA TUCUMANA ON DIFFERENT HOST PLANTS.

Number of Number of eggs per egg mass
Plant species Egg mass location egg masses found (Mean SD)

Citrus limon Leaf 96 9.7 3.7ab
Stem/shoot 17 8.8 3.1
Cedrela lilloi Leaf 12 11.8 3.1
Stem/shoot 8 5.9 1.7
Zea mays Leaf 21 11.8 3.4
Ligustrum lucidum Leaf 9 7.8 2.9
Psidium guajava Leaf 5 9.2 4.1
Urera caracasana Leaf 1 6
Stem/shoot 1 8
Diadenopteryx sorbifolia Leaf 2 10.0 2.8
Bauhinia forficata Leaf 2 7 1.4
Sorghum halepense Leaf 1 10
Ruprechtia laxiflora Leaf 1 12

Means followed by the same letter are not significantly different (P > 0.05; Tukey test).


emerged from the egg masses laid on stems (Table
3, Fig. 4). Multiparasitism of the same egg mass
was very unusual, occurring in only 2 egg masses
among the 176 egg masses examined, both on
lemon leaves (the first egg mass was collected on
9 Jan 2004, with the total number of host eggs of
12; 10 of those were parasitized by G. tuberculife-
mur and 2 by G. annulicornis). The second egg
mass was collected on 27 Feb 2004, with the total
number of host eggs of 6; 3 of them were parasit-
ized by G. tuberculifemur and 1 by G. metanotalis.
From the parasitized egg masses located on trees
or robust scrubs, G. annulicornis was consistently
obtained more frequently (in up to 80% of cases)
than G. metanotalis or G. tuberculifemur. On corn
plants, the dominant species was G. metanotalis,


50
45
S40
8 35
30
25
20-
n 15 -
E 10
0 .
5
0-


E G. metanotalis
G. tuberculifernur
O G, annulicornis






I H


Oct Nov Dec Jan Feb Mar
Fig. 3. Seasonal distribution of the egg parasitoids of
Oncometopia tucumana in an abandoned citrus orchard
at Horco Molle (Tucuman Province, Argentina).


which emerged from 34%
were examined) (Table 3).


of the eggs (247 eggs


DISCUSSION

In the old citrus orchard surrounded by the
dense vegetation of the Yunga's rainforest, 0. tu-
cumana occurred throughout spring to late fall.
We do not have evidence of where this species
overwinters. However, we presume that like Tapa-
josa rubromarginata (Signoret), a common proco-
niine sharpshooter that inhabits the same area,
0. tucumana overwinters as adult. Also, like On-
cometopia alpha Fowler attacking Salix sp. and
Populus sp. in the USA (Nielson et al. 1975), 0. tu-
cumana has a reproductive quiescence during
approximately 6 months (Apr to Oct). Similar to
H. vitripennis (Daane et al. 2004), we found egg
masses about 2 weeks before any adult 0. tucu-
mana was collected, indicating that this sharp-
shooter exploits some plants located outside of the
examined area and visits the citrus orchard to ovi-
posit during hours different from our sampling ef-
fort (mostly near midday). The adult sex ratios
were male biased, but females were proportionally
more abundant during the end of summer and the
beginning of fall. Similar observations were made
for the corn leafhopper, Dalbulus maidis (DeLong
& Wolcott) in the same area (Virla et al. 2003).
The Proconiini and other xylem feeding leaf-
hoppers have evolved with many unusual adapta-
tions such as host switching to maximize nutrient
uptake (Mizell & Andersen 2001). The ability to
disperse, locate, and utilize host plants is essen-
tial for the proconiine sharpshooters because the







Florida Entomologist 91(1)


Fig. 4. Oncometopia tucumana egg mass coated with brochosomes on a citrus stem, and a female of Gonatocerus
annulicornis leaving after parasitizing it (inside the circle).


nitrogen in the xylem fluid is diluted and highly
variable, not only between the host plant species,
but also within a single plant over time (Tipping
et al. 2004). This triggers different seasonal pat-
terns in utilization of the host plants (Brodbeck et
al. 1990; Milanez et al. 2001). We found that O. tu-
cumana exploits 12 host plants from 11 families,
both native and introduced. Similar observations
were made for H. vitripennis in the USA, which is
highly polyphagous and feeds on hundreds of
plant species from at least 37 families (Andersen
et al. 2005). Oncometopia tucumana showed dif-
ferent patterns of plant utilization for feeding and
oviposition. Adults preferred to feed on shrub ver-
bena and yellow trumpet-flower whereas the pre-
ferred plants for oviposition were lemon, Tu-
cuman cedar, and corn. Homalodisca vitripennis
has similar patterns, showing different host pref-
erences for feeding and oviposition (Redak et al.
2004; Daane et al. 2004).
Generally, the egg masses of 0. tucumana were
deposited on the abaxial surface of the leaves
(only 1 per leaf), but in lemon, Tucuman cedar
and flame berry, we found about 1/3 of them on
green stems. On average, the egg masses, coated


with brochosomes, contained 9.5 eggs. The ovipo-
sition habits of this sharpshooter are consistent
with those recorded for some other members of
Proconiini (Turner & Pollard 1959; Almeida &
Spotti Lopes 1999; Rakitov 2004). On the con-
trary, Logarzo et al. (2006) reported that Anacu-
erna centrolinea (Melichar) usually lays more
than 1 egg mass per leaf, each containing 3.9 eggs
on average, and these small egg masses are laid
on both sides of the leaf.
About 10% of the collected egg masses were
preyed upon. Laboratory assays revealed that an
unidentified species of Nabidae (Hemiptera), col-
lected from grasses at Horco Molle, preyed upon
eggs of 0. tucumana and T rubromarginata. The
eaten eggs look empty but had the cuticle and the
chorion intact (E.G.V., unpublished data). How-
ever, by far the most important egg mortality factor
was egg parasitism. In the USA, the summer gen-
eration ofH. vitripennis collapses due to the heavy
egg parasitism and other mortality factors (Castle
et al. 2005). Egg masses of 0. tucumana were at-
tacked by 3 mymarid parasitoids (G. annulicornis,
G. metanotalis and G. tuberculifemur) that all to-
gether produced egg mortality near to 60%.


March 2008







Virla et al.: Bionomics of the Sharpshooter Oncometopia tucumana


TABLE 3. EGGS PARASITOIDS OF ONCOMETOPIA TUCUMANA ON DIFFERENT HOST PLANTS.

% of parasitoid species attacking eggs
Number of % of
eggs (egg parasitized Gonatocerus Gonatocerus Gonatocerus
Host plant Substrate masses) eggs annulicornis metanotalis tuberculifemur

Citrus limon Leaf 928 (96) 64.9 81.2 18.8
Stem 149 (17) 53.0 100.0
Cedrela lilloi Leaf 142 (12) 57.0 80.0 20.0
Stem 47 (8) 34.0 100.0
Zea mays Leaf 247 (21) 72.9 11.1 77.8 11.1
Ligustrum lucidum Leaf 70 (9) 34.3 100.0
Psidium guajava Leaf 46(5) 65.2 100.0
Urera caracasana Leaf 6(1) 0.0
Stem 8(1) 100.0 100.0
Diadenopteryx sorbifolia Leaf 20 (2) 100.0 100.0
Bauhinia forficata Leaf 14 (2) 42.9 100.0
Sorghum halepense Leaf 10 (1) 0.0
Ruprechtia laxiflora Leaf 12 (1) 0.0

*Only appears in multiparasitized egg masses, see text.


Velema et al. (2005) stated that the brocho-
somes covering the egg masses of H. vitripennis
significantly decreased oviposition efficacy of Go-
natocerus ashmeadi Girault. Although the egg
masses of 0. tucumana were heavily coated with
brochosomes, egg parasitoids successfully at-
tacked at least 30% of the eggs, reaching 76.2%
parasitization rate on corn. Gonatocerus annuli-
cornis was the most effective parasitoid in the
highly diverse, elevated foliage environment,
emerging from over 80% of the parasitized eggs
(including on lemon). The incidence ofG. metano-
talis on scrubs or trees was low (less than 20%),
but this species was responsible for a 77.8% para-
sitism of the egg masses on corn plants. The inci-
dence of G. annulicornis parasitizing eggs of
0. tucumana on corn was low. Perhaps, the guild
of egg parasitoids is structured by parasitoid hab-
itat preference and not as much by interspecific
competition as suggested by Hoddle & Irvin
(2003) for G. ashmeadi, G. triguttatus, and G. fas-
ciatus attacking egg masses of H. vitripennis. In-
terestingly, G. tuberculifemur was always found
in the multiparasitized egg masses with both G.
annulicornis and G. metanotalis.
In California, grape, citrus, apple,Xylosma sp.,
cherry, and flowering pear were the most pre-
ferred ovipositional plants for H. vitripennis
(Blua et al. 1999; Daane & Johnson 2005). All of
these plants are trees, vines, or shrubs. The abil-
ity of G. annulicornis to successfully locate and
oviposit in these plants offers a great possibility
for its utilization in a new association biological con-
trol program. Since Mar 2001, this parasitoid has


been successfully reared from eggs ofH. vitripen-
nis at the USDA-APHIS Mission quarantine facil-
ity in Edinburg, Texas (Logarzo et al. 2005). Go-
natocerus annulicornis is widely distributed in
Argentina (Jujuy, Salta, Tucuman, Misiones, For-
mosa, Corrientes, Catamarca, San Juan, and
Mendoza Provinces), including some very dry ar-
eas as Lujan de Cuyo in Mendoza Province or
Caucete in San Juan Province (G.A.L., unpub-
lished data.) suggesting that this parasitoid spe-
cies could be efficient in this kind of environment.
This work encourages further laboratory stud-
ies on the biology and host range ofG. annulicor-
nis, in order to assess its potential as a neoclassi-
cal biological control agent for H. vitripennis.

ACKNOWLEDGMENTS
We thank Eduardo Frias and Erica Luft Albarracin
for technical assistance in the field works, and Juan
Briano for thoughtful comments on the manuscript. In
addition, we are indebted to the curators of IMLA and
MLPA for the loans of specimens. Finally, we thank the
Escuela de Agricultura y Sacarot6cnia, Universidad Na-
cional de Tucuman for letting us to take the samples in
the citrus orchard at the Horco Molle site.

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Florida Entomologist 91(1)







Virla et al.: Fall Armyworm Strains in Argentina


FALL ARMYWORM STRAINS (LEPIDOPTERA: NOCTUIDAE)
IN ARGENTINA, THEIR ASSOCIATE HOST PLANTS AND RESPONSE
TO DIFFERENT MORTALITY FACTORS IN LABORATORY

EDUARDO G. VIRLA, ANALIA ALVAREZ, FLAVIA LOTO, LICIA M. PERA AND MARIO BAIGORI
PROIMI-Biotecnologia, Divisi6n de Control Biol6gico, Avenida Belgrano y Pje. Caseros, T4001 MVB,
San Miguel de Tucuman, Tucuman, Argentina

ABSTRACT

The aim of this research was to identify the existence of different Spodoptera frugiperda
(J.E. Smith) (FAW) host strains in Argentina, and to determine their behaviors in the pres-
ence of different mortality factors. Populations belonging to these strains were tested with
the pesticides chlorpyriphos and cypermethrin, transgenic corn germplasms expressing Cry
proteins lAb or 1F, and an indigenous Bacillus thuringiensis strain. The relation of these
strains with the host plant species and crop utilization, subsistence or commercial ones, is
discussed. The response to the assayed insecticides, Bt transgenic corn and Bt suspension
was diverse, showing wide variability in mortality rates. This research validates the need of
intensive studies relating resistance phenomena with the differential behavior of the host
strains inhabiting Argentina. Host plant and crop utility is not a determinant for the iden-
tity of the colonizing strain, so molecular identification of the strains is highly recommended
before study of any aspect of the FAW in Argentina.

Key Words: Spodoptera frugiperda, mitochondrial DNA, transgenic corn, Bacillus thuring-
iensis, pesticides

RESUME

El objetivo de esta investigaci6n fue establecer la existencia de diferentes lines o cepas del
cogollero del maiz, Spodoptera frugiperda (J. E. Smith), en Argentina, y determinar su com-
portamiento frente a diversos factors de mortalidad. Poblaciones correspondientes a dife-
rentes cepas fueron testadas con los insecticides clorpirifos y cipermetrina, maices
transg6nicos que expresan las proteinas Cry lAb y 1F, y una cepa native de Bacillus thur-
ingiensis. Se discute la relaci6n entire las cepas, las plants desde donde fueron colectadas y
el objetivo agricola del cultivo, subsistencia o commercial. La respuesta a los insecticides, mai-
ces Bt transg6nicos y a la suspension de Bt fue diverse, mostrando una amplia variabilidad
en las tasas de mortalidad. Esta investigaci6n exhorta la necesidad de intensificar studios
relacionados a los fen6menos de resistencia, y a determinar el comportamiento diferencial
de las cepas del cogollero que afectan cultivos en Argentina. La plant hospedadora y el tipo
de cultivo no es determinante de la identidad de la cepa que lo coloniza, por lo que es alta-
mente recomendable realizar la identificaci6n de las mismas mediante t6cnicas moleculares
antes de estudiar cualquier aspect relacionado a esta especie plaga en Argentina.


Translation provided by the authors.


The fall armyworm (FAW), Spodoptera fru-
giperda (J. E. Smith) (Lepidoptera: Noctuidae), is
a polyphagous pest that causes important dam-
age in different regions of America (Sparks 1979).
The significance of this pest in Argentina was dis-
cussed by Virla et al. (1999).
There are at least 2 morphologically identical
host strains of FAW. The rice strain is associated
with rice and bermudagrass, while the corn strain
predominates on corn, sorghum, and cotton, al-
though this host specificity is not completely exclu-
sive (Pashley 1986; McMichael & Prowell 1999).
Additional behavioral and physiological distinc-
tions between these strains have been reported,
including differences in pesticide resistance, sus-
ceptibility to transgenic plants, and nutritional ad-


aptation (Pashley 1988a, b; Pashley et al. 1995;
Veenstra et al. 1995; Adamczyk et al. 1997).
The rice and corn strains can be distinguished
by several restriction fragment-length polymor-
phisms in mitochondrial DNA (mtDNA). Lu &
Adang (1996) reported the Mspl mtDNA restric-
tion pattern as a diagnostic marker for corn and
rice strains. Later, a polymorphic MspI restriction
site located in the mitochondrial cytochrome oxi-
dase subunit I (COI) gene was used for strain
identity (Levy et al. 2002).
For many years, control of FAW has been ex-
clusively dependent on insecticides; as a result,
this pest has developed resistance to major
classes of insecticides in many areas (Yu et al.
2003). Resistance of FAW to various carbamate,







Florida Entomologist 91(1)


organophophate, and pyrethroid insecticides
were observed in field strains collected from corn
in north, central, and south Florida (Yu 1991,
1992). In Argentina, the organophosphate chlo-
rpyriphos has been extensively used. Berta et al.
(2000) demonstrated that the application of this
pesticide did not reduce FAW populations but
drastically diminished the establishment of the
parasitoid Campoletis grioti (Blanchard) (Hy-
menoptera, Ichneumonidae).
Genetically modified or transgenic maize (Zea
mays L.) may improve agricultural productivity
in controlling FAW in Argentina (Frizzas 2003).
For example, MON810 (Monsanto Company, St.
Louis, MO) expressing Bacillus thuringiensis var.
kurstaki (Bt) CrylAb endotoxins, provided high
dose and season-long control of another lepi-
dopteran pest of maize, the European corn borer
Ostrinia nubilalis (Hiibner) (Koziel et al. 1993;
Armstrong et al. 1995). Another viable alterna-
tive for insect control in agriculture is the use of
entomopathogens. Among these, Bt is the most
widely employed. The use of this microorganism
is compatible with sustainable and environmen-
tally friendly agricultural practices.


The purpose of this work was to identify FAW
host strains in Argentinean territory and to deter-
mine their behaviors in the presence of pesticides,
transgenic corn plants or Bt water suspension.

MATERIAL AND METHODS

Origin and Maintenance of Fall Armyworm Colonies

Larvae of FAW were collected as 3rd to 6th in-
stars from different localities in northern Argen-
tina (Table 1). Larvae were manually collected
from the whorl of the plants and placed individu-
ally in glass tubes (12-cm length x 1.5-cm diame-
ter) with host leaves and carried to the laboratory.
Adults were maintained in polyethylene-
terephthalate cylindrical cages (30-cm high x 10-
cm diameter). For aeration, the top was closed
with a nylon mesh cloth. These cages contained
pieces of paper that allowed the females to ovi-
posit. Food was provided via a cotton plug satu-
rated with a mixture of honey and water (1:1 vol/
vol). The cages were checked daily for oviposition
and adult mortality; egg masses were collected
and deposited in glass tubes as mentioned above.


TABLE 1. ORIGIN OF FAW POPULATIONS.

Altitude Host plant
FAW Locality (Province) (m) (purpose) Date of collection

1 La Morocha (La Rioja) 914 Corn 11/XI/05
S 29 35'03.9-W 66 49'46.9) (Subsistence)
3 Campo Largo (Chaco) 110 Corn 02/1/06
S 26 46'57.3-W 60 49'17.6 (Commercial)
4 Gral. Capdevila (Chaco) 115 Sorghum 02/1/06
S 2725'39.8-W 61 29'50.4 (Subsistence)
5 Quimili (S. del Estero) 144 Sorghum 02/1/06
S 2738'39.0-W 62 21'18.1 (Subsistence)
6 La Virginia (Tucuman) 397 Sorghum 19/XII/05
S 26 44'43.3-W 64 47'41.6 (Commercial)
7 San Jos6 (Catamarca) 1978 Corn 18/XII/05
S 26 48'40.6-W 66 04'30.4 (Subsistence)
8 Purmamarca (Jujuy) 2275 Corn 12/1/06
S 23 44'47.8-W 65 28'50.5 (Subsistence)
9 Guemes (Salta) 790 Corn 12/1/06
S 24 47'23.2-W 65 02'10.8 (Commercial)
10 Rosario de la Frontera (Salta) 965 Corn 12/1/06
S 25 58'25.9-W 65 05'08.6 (Commercial)
11 El Talar (Jujuy) 365 Corn 12/1/06
S 23 42'57.8-W 64 31'49.6 (Subsistence)
12 Metan (Salta) 807 Corn 12/1/06
S 25 38'31.5-W 64 56'50.8 (Commercial)
14 Barcena (Jujuy) 1856 Corn 12/1/06
S 23 59'10.5-W 65 27'15.3 (Subsistence)
16 Vicuna Makena (C6rdoba) 224 Corn 31/1/06
S 33 55'51.2-W 64 21'12.1 (Commercial)
17 Castelli (Chaco) 110 Corn 12/III/06
S 25 57'19.4-W 60 35'49.7 (Commercial)
18 El Manantial (Tucuman) 445 Corn 12/III/06
S 26 49'50.2-W 65 16'59.4 (Subsistence)


March 2008







Virla et al.: Fall Armyworm Strains in Argentina


Once emerged, the neonate larvae were placed in
250-cc plastic pots covered with nylon mesh
cloth until they reached the 3rd instar. These
older larvae were isolated in glass tubes to pre-
vent cannibalism.
All cultures were maintained separately in the
laboratory on an artificial diet (Osores et al.
1982), in rooms at 25 0.5C, 14:10 (L:D) artificial
photoperiod, and 70 15% RH. Data were re-
corded by a HOBO@ data logger every hour. All bi-
ological assays were done with individuals of the
second laboratory generation and under the same
conditions used for FAW population maintenance.
Mortality was calculated for both treatments and
controls. Larvae that could not crawl after being
touching with a brush were considered dead.

DNA Preparation and PCR Analysis

Total DNA was isolated from individual FAW
larvae with a commercial kit (GE Healthcare ge-
nomic prepTM Cells and Tissue DNA). All genomic
DNAs used in this study were tested by PCR for
the mitochondrial COI gene restriction fragment-
length polymorphism to confirm strain identity.
PCR amplification of genomic DNA was per-
formed in a 25-pL reaction mix containing 2.5 pL
10 x STR reaction buffer (Promega), 20 ng total
DNA, 20 pmol L- of JM76 and JM77 primers and
2 units of Taq DNA polymerase (Promega). Am-
plification was performed on a DNA thermocycler
(Perkin-Elmer) with the following program: an
initial incubation at 94C (5 min), followed by 35
cycles of 94C (1 min), 58C (1 min), 72C (2 min),
and a final segment of 72C for 7 min. Samples of
8-10 pL were electrophoresed in 7% PAGE gel,
followed by ethidium bromide staining and pho-
tography under UV light. The PCR amplified
DNA products (0.5 uL) were digested in sepa-
rated reactions with either SacI or MspI restric-
tion endonuclease. Samples were incubated at
37C for 1 h. The restriction enzyme profiles were
also visualized with ethidium bromide on an 8.0%
PAGE gel.
Primers were synthesized by Tecnolab S.A.
They included JM 76 (5'-GAGCTGAATTAGG(G/
A)ACTCCAGG-3') and JM 77 (5'-ATCACCTCC(A/
T)CCTGCAGGATC-3') (Levy et al. 2002).

Bioassays with Pesticides

Two insecticides that are widely used in corn
production, chlorpyriphos (3.33 cc/L H20) and
cypermethrin (0.53 cc/L H20), were tested. Both
insecticides were obtained commercially. Single
corn leaves from a non-transgenic hybrid known
as "precomercial 22" were submerged in insecti-
cide solutions for 15-20 s and then were left to dry
for 2 h before the bioassay was started. Single
control leaves were placed in distilled water.


For both insecticides and the control, 3rd in-
stars (Stadler 1996) were held in separate glass
tubes (10 cm length x 1 cm diameter) and were
supplied with treated pieces of leaf (about 2 cm2
each). Cotton plugs closed the vials. Each experi-
ment was replicated 6 times with 10 larvae (total
n = 60). Mortality data were collected after 6, 24,
30, 48, 54, 72, and 78 h after exposure.

Bioassays with Transgenic Corn Plants

Two newly developed transgenic corn germ-
plasms, NK 120 TDmax (Syngenta Seeds) ex-
pressing the Cry lAb protein, and Herculex I
(Dow AgroSciences) expressing the Cry 1F pro-
tein, were tested. The former germplasm report-
edly provides partial control of FAW, while the
latter germplasm reportedly provides complete
protection against FAW. The non-transgenic hy-
brid "precomercial 22" was used as a control.
For each germplasm, 6 replicates of 10 newly-
emerged 1t instars were held in separate 2.0-mL
Eppendorf vials. Each larva was supply with a
piece of leaf (about 2 cm2) that was replaced when
necessary. Mortality data were collected after 6,
24, 30, 48, 54, 72, and 78 h after exposure.

Bioassays with Bacillus thuringiensis (Bt)

A native B. thuringiensis strain RT from our
own culture collection was used throughout this
study. The partial nucleotide sequence of the 16S
rRNA from Bt RT was deposited in Genebank da-
tabase under accession number EF638795. Bacte-
ria were grown in LB-agar. The presence of crys-
tal proteins was checked with Coomasie blue re-
agent (Sharif & Alaeddinoglu 1988).
Six replicates of 10 newly-emerged 1t instars
were held in separate 2.0-mL Eppendorf vials.
Each larva was supply with a piece of artificial
diet (approximately 0.25 cm2) immersed in a sus-
pension of Bt in water (DO600 = 1.7; 8.9 x 106 CFU).
Controls were maintained with a similar piece of
artificial diet but immersed in distilled water.
Mortality data were collected 6, 24, 30, 48, 54, 72,
78, 92, 98, 116 h after exposure.

Data Analysis

Mean survivorship was analyzed by analysis of
variance (ANOVA), and means were compared
with the Tukey test (P < 0.05). Lethal times for
50% of the population (LT,,) were computed by
Probit analysis (Minitab 2004). Mean survival
time data were organized into a 1-0 matrix and
the similarity degree among the FAW populations
was estimated with the simple matching coeffi-
cient. Clusters were then constructed by the un-
weighted pair group method with arithmetic av-
erage (UPGMA) algorithm with the NTSYS pro-
gram (Rohlf 1998).







Florida Entomologist 91(1)


March 2008


RESULTS AND DISCUSSION


The existence of 2 FAW host strains
tablished in the USA (Pashley 1986,
and Brazil (Busato et al. 2004), and i
presence was mentioned in Mexico
wards et al. 1999). No report has beei
the presence of these host-strains or tl
iors in Argentina.
Strain specificity of FAW samples fr
locations in Argentina was determine
presence of diagnostic mitochondrial n
cently reported by Nagoshi et al. (200
work, the fragment produced by PCR
tion with the JM-76/JM-77 primers
rately digested with SacI and MspI rest
zymes. The amplified product from the
was cut once by SacI but not by MspI, w
corn strain DNA showed a reciproc;
Thus, according to these molecular ma
ulations of 4 rice strains and 11 corn st
found in Argentina (Figs. 1 and 2). 1
also showed that a small fraction of ric
dividuals readily use corn as a host. T]
in host usage also was established i
(1989) and McMichael & Prowell (1999
An important consideration for th
ment of this pest is that differences we
the response of the rice and corn strain
ent mortality factors such as insectici
pathogens (Nagoshi & Meagher 2004).
of similarity among the FAW popul
studied based on their mean survival
trained in the presence of pesticides,
corn plants, or Bt water suspensions. A
the dendrogram (Fig. 2), the numeric.
clearly revealed 2 major clusters at a
level of 54%. Cluster A comprised sever
ulations, all of these were identified as



MnlI SacI















Fig. 1. PAGE gel displaying PCR-am]
ment produced by the JM-76/JM-77 primer
with the specified restriction enzymes. Resp
C, and R denote molecular marker, corn str
strain.


is well es-
1988a, b),
ts possible
(Lopez-Ed-
n given for
ieir behav-

om several
led by the
markers re-
6). In that
amplifica-
was sepa-
triction en-
rice strain
whereas the
al pattern.
rkers, pop-
rains were
?he results
e strain in-
his overlap
)y Pashley
e manage-
e manage-


S1fi
______ 1_ C C Sb
________11 C C Sb
to C C Cm
17 C C Ca
________12 C C 0i.
j C C Ci
7 C C Sb
4 R SSb
- R S Sb
14 R C Sb
9 C C Ca
6 C S C.
S C C 9b
16 R C C-
- ISl C C Sb
6 , '6l


Coeihoat


Fig. 2. Dendrogram showing clustering (groups A
and B), and relationships of FAW populations based on
their survival time obtained in the presence of insecti-
cides, transgenic corns or Bt RT water suspension. As-
sociations were produced by using UPGMA clustering
method. Strain: corn (C), rice (R). Host plant: corn (C)
and sorghum (S). Purpose: subsistence (SB), commer-
cial (CM). for FAW population references see Table 1.


re found in while cluster B included both rice (4) and corn (4)
Is to differ- FAW strains. In addition, rice strain 16 showed a
des and/or level of similarity of 59% with the other rice strain
The degree populations (4, 5, and 14), which displayed a
nations was higher level of similarity between them (75%). In-
Il time ob- terestingly, rice strain 16 was collected from a
transgenic completely different geographic location (Table 1).
.s shown in Rice strain populations 4 and 5 shared the same
al analysis host usage and had a similarity level of 90%.
similarity Five of the 8 FAW populations collected from
SFAW pop- subsistence crops were found in group B (Fig. 2).
corn strain, Only 1 of the 11 corn strain populations was from
sorghum, whereas 2 of the 4 rice strain popula-
tions were collected from corn.
Pesticides are a critical component of insect
pest management in corn production. In general,
the application of chlorpyriphos or cypermethrin
resulted in more rapid death of FAW populations
than the use of transgenic corn or Bt water sus-
S500pb pension; with the LT5, values ranged from 3.01 to
20.7 h (Table 2). FAW population 12 displayed a
completely different result. After 78 h in the as-
S say, 50% mortality with LT5, of 76.34 h was ob-
tained. This mortality level was the same as that
found in the presence of Bt water suspension (Ta-
ble 4). However, assays conducting with corn
plants expressing either the Cry 1F or Cry lAb
00pb gene resulted in 86.67 and 85.00% mortality, re-
spectively (Table 3).
plified frag- Since the first genetically engineered corn was
s (F) and cut commercialized, there have been numerous ad-
)ectively, M, vancements for insect control with transgenic
ain, and rice technology. In this work, the impact of transgenic
corn expressing Cry 1F or Cry lAb against FAW







Virla et al.: Fall Armyworm Strains in Argentina


TABLE 2. MEAN SURVIVAL TIME*, LETHAL TIME (LTs,), AND MORTALITY OF FAW POPULATIONS EXPOSED TO PESTICIDES
(CHL: CHLORPYRIPHOS; CYP: CYPERMETHRIN; CONTROL: DISTILLATED WATER).

Mean survival time (h) LTs, (h) Mortality (%)

FAW Strain CHL CYP Control CHL CYP CHL CYP Control

1 C 2.95 ab 6.10 abc 74.40 b 6.63 5.53 100.00 95.00 5.0
3 C 4.73 bc 16.35 d 74.30 b 7.99 20.70 100.00 100.00 6.7
4 R 1.42 ab 3.15 ab 74.70 b 4.80 6.50 100.00 100.00 5.0
5 R 1.33 ab 2.05 ab 75.70 b 6.63 4.49 100.00 100.00 8.3
6 C 1.33 ab 1.80 ab 76.60 b 4.72 4.12 100.00 100.00 5.0
7 C 1.63 ab 11.40 bcd 76.20 b 3.89 12.32 100.00 95.00 5.0
8 C 1.75 ab 4.47 abc 74.40 b 5.05 8.64 100.00 100.00 5.0
9 C 7.07 c 10.47 abcd 72.60 ab 12.86 14.06 100.00 95.00 11.7
10 C 4.58 ab 13.47 cd 65.00 a 4.94 14.58 100.00 93.33 21.7
11 C 7.15 c 8.67 abcd 76.60 b 11.60 12.41 98.33 98.33 5.0
12 C 1.50 ab 55.17 e 75.20 b 4.87 76.34 100.00 50.00 5.0
14 R 2.42 ab 10.12 abcd 76.60 b 5.44 13.57 100.00 100.00 5.0
16 R 2.13 ab 3.13 ab 76.10 b 4.62 4.61 100.00 100.00 6.7
17 C 1.92 ab 13.90 cd 76.70 b 5.16 15.15 100.00 90.00 3.3
18 C 1.00 a 1.00 a 76.80 b 3.10 3.01 100.00 100.00 3.3

*To facilitate the comparison, we arbitrarily assign 1 h survival for those larvae dead before the first observation (6 h). In each
column, means followed by different letters are significantly different (P < 0.05) (ANOVA; Tukey analysis).


populations range from slight to highly toxic. How- onies tested with corn expressing Cry lAb protein.
ever, some considerations must be made. First, as Luo et al. (1999) also reported high toxicity of Cry
expected, the Cry 1F transgene provided higher 1F protein against FAW larvae. Second, trans-
mortality than corn producing Cry lAb (83.5 genic corn displayed differential mortality with re-
6.2% vs. 68.8 6.8%, respectively). As shown in Ta- spect to the rice strain populations. Rice strain
ble 3 and during the 78-h assays, 73% of the FAW populations 4 and 5 from subsistence sorghum
populations exposed to corn with CrylF resulted sustained markedly less mortality than all other
in mortality values higher than 75%, while this populations. It is not known why these popula-
percentage was achieved by only a 40% of the col- tions were more resistant than the others.


TABLE 3. MEAN SURVIVAL TIME, LETHAL TIME (LT.0), AND MORTALITY OF FAW POPULATIONS FEEDING ON EITHER GE-
NETICALLY MODIFIED OR NON-TRANSGENIC CORNS.

Mean survival time (h) LT5, (h) Mortality (%)

FAW Strain Cry 1F Cry lAb Control Cry 1F Cry lAb Cry 1F Cry lAb Control

1 C 55.00 defg 61.40 efgh 76.20 bc 62.70 75.28 85.00 53.33 16.67
3 C 45.50 cd 57.60 cdef 76.70 bc 52.26 67.06 98.33 70.00 6.67
4 R 72.10 h 74.20 i 73.70 bc 120.16 97.70 21.67 20.00 21.67
5 R 62.80 gh 68.90 hi 73.40 bc 92.64 206.26 36.67 20.00 8.33
6 C 41.80 c 45.70 b 74.10 bc 48.32 53.09 100.00 90.00 16.67
7 C 46.10 cde 58.00 defg 75.20 bc 53.09 66.54 96.67 71.67 13.33
8 C 48.40 cdef 56.40 bcde 75.50 bc 55.77 64.57 93.33 81.67 8.33
9 C 28.10 b 46.90 bc 76.80 bc 34.91 54.53 100.00 96.67 1.67
10 C 56.50 fg 59.20 defgh 74.90 bc 24.90 72.87 66.67 56.67 18.33
11 C 53.60 defg 68.40 fghi 78.00 c 58.47 90.90 88.33 45.00 0.00
12 C 55.50 efg 58.60 defgh 76.80 bc 62.37 66.31 86.67 85.00 10.00
14 R 15.50 a 28.10 a 63.90 a 24.27 36.72 100.00 93.33 30.00
16 R 55.30 efg 54.20 bcde 73.40 bc 62.52 61.20 93.33 98.33 16.67
17 C 51.90 def 62.80 efgh 78.00 c 59.43 73.31 98.33 55.00 0.00
18 C 53.10 defg 50.30 bcd 70.40 ab 59.44 54.51 88.33 95.00 28.33

In each column, means followed by different letters are significantly different (P < 0.05) (ANOVA; Tukey analysis).







Florida Entomologist 91(1)


March 2008


TABLE 4. MEAN SURVIVAL TIME, LETHAL TIME (LTs,), AND MORTALITY OF FAW POPULATIONS EXPOSED TO EITHER Bt-
TREATED OR UNTREATED ARTIFICIAL DIET.

Mean survival time (h) Mortality (%)
LTo (h)
FAW Strain Bt RT Control Bt RT Bt RT Control

1 C 99.50 cd 114.60 c 149.27 26.67 1.7
3 C 94.80 cd 114.90 c 124.52 38.33 3.3
4 R 106.80 d 113.30 bc 253.79 10.00 3.3
5 R 91.80 cd 108.40 bc 191.44 26.00 8.3
6 C 67.10 ab 102.20 ab 78.35 71.67 25.0
7 C 89.10 bcd 116.00 c 121.24 35.00 0.0
8 C 56.60 a 115.00 c 64.33 75.00 1.7
9 C 93.90 cd 112.60 bc 136.23 38.33 8.3
10 C 66.90 ab 110.90 bc 77.21 65.00 11.7
11 C 83.90 bcd 110.10 bc 110.08 53.33 10.0
12 C 86.30 bcd 111.90 bc 107.14 50.00 8.3
14 R 97.70 cd 113.50 bc 171.02 21.67 5.0
16 R 88.50 bcd 116.00 c 125.32 33.33 0.0
17 C 56.90 a 115.60 c 65.43 91.67 1.7
18 C 82.00 bc 114.60 c 104.52 45.00 1.7

In each column, means followed by different letters are significantly different (P< 0.05) (ANOVA; Tukey analysis).


The use of Bt products as an alternative to
chemical insecticides has encouraged many re-
search centers to focus their efforts in the isola-
tion of native strains that provide mortality to
FAW. As shown in Table 4, although the assays
were conduced with artificial diet, the native
strain Bt RT was in general active against FAW
populations. Particularly interesting was the re-
sponse of rice strain colonies to this Bt water sus-
pension; all of these populations presented low
mortality values with LT50 values ranging from
125.32 to 253.79 h. Therefore, strain identity
must be taken into consideration when evaluat-
ing the effectiveness of new biological agents.

ACKNOWLEDGMENTS

We thank Ing. Auali and Mercado (SINER S.A.) for
providing the pesticides used in the assays, Ernesto
Teran Vega for providing the seeds, and Eduardo Frias
and Esther Mercado for technical assistance. We thank
the editor, James Nation, and the 2 anonymous review-
ers for comments on an earlier draft. The present work
was supported by grants PICTO-UNT no. 761, and PIP
no. 6062 CONICET.

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Florida Entomologist 91(1)


March 2008


SOLENOPSIS ENIGMATIC, A NEW SPECIES OF INQUILINE ANT FROM
THE ISLAND OF DOMINICA, WEST INDIES (HYMENOPTERA: FORMICIDAE)

MARK DEYRUP AND ZACHARY A. PRUSAK2
'Archbold Biological Station, P.O. Box 2057, Lake Placid, FL 33862
E-mail: mdeyrup@archbold-station.org

2The Nature Conservancy, 222 South Westmonte Drive, Suite 300,Altamonte Springs, FL 32714
E-mail: zprusak@tnc.org

ABSTRACT

A new species of ant, Solenopsis enigmatica, is described from 2 dealate queens and 3 work-
ers collected from nests of Pheidole antillana Forel in rainforest on the island of Dominica,
West Indies. The queen of S. enigmatica is similar to that of another inquiline, S. phoretica
Davis and Deyrup, known only from 1 queen collected in Florida. The 2 species differ in man-
dibular dentition and other ways. Worker S. enigmatica do not closely resemble those of
other known species. They lack clypeal carinae, have short antennal scapes, and have long,
coarse hairs arising from conspicuous punctures. The presence of workers suggests that S.
enigmatica might be a temporary nest parasite, but many questions remain about the rela-
tionship of this species to its host.

Key Words: parasitic ant, parasitic Solenopsis, parasitic fire ant, insects of Dominica

RESUME

Una nueva especie de hormiga, Solenopsis enigmatica, es descrita de 2 reinas sin alas y 3
trabajadores recolectados en nidos de Pheidole antillana Forel en un bosque pluvial en la
isla de Dominica. La reina de S. enigmatica es similar a otra hormiga inquilina, S. phoretica
Davis y Deyrup, conocida solamente por 1 reina recolectada en la Florida. Las 2 species se
diferencia por los dientes de la mandibula y en otros caracteres. Los trabajadores de S. enig-
matica no se parecen a las otras species conocidas. Ellos carecen de la carinae del clipeo, tie-
nen el segment del escape de la antena mas corto y tienen setas largas y gruesas saliendo
de punteaduras conspicuas. La presencia de los trabajadores sugiere que S. enigmatica
puede ser un parasito temporaneo del nido, pero quedan muchas preguntas sobre la relacion
entire esta especie y su hospedero.


Solenopsis is a moderately large genus with
over 180 described species (Bolton 1995) and a
large but unknown number of undescribed species.
Most Solenopsis species are small, cryptic and
poorly known, ecologically unrelated to the small
number of large, open-foraging, notorious species
such as S. invicta Buren, S. geminata (Fabricius)
and S. saevissima (F. Smith). Some small subterra-
nean species live next to nests of other ants and
prey on the larvae of their neighbors (Hdlldobler &
Wilson 1990). A few South American Solenopsis
species are workerless parasites, whose peculiar
morphology caused them to be placed in the gen-
era Labauchena or Paranamyrmex until Etters-
hank (1966) synonymized those genera with Sole-
nopsis. Recently, a new species of Solenopsis, S.
phoretica, was described, based on a single dealate
queen found clinging to the petiole of a queen of
Pheidole dentata Mayr (Davis & Deyrup 2006). It
is suspected that this queen represents a parasitic
species, considering the situation of the specimen
and certain morphological features. At the time of
the description of S. phoretica, this species did not
appear to be closely related to the known parasitic


Solenopsis, or any other known species of Solenop-
sis (Davis & Deyrup 2006). Soon after the descrip-
tion of S. phoretica was published, another species
of inquiline Solenopsis was discovered on the is-
land of Dominica in the West Indies. This species
appears to be closely related to S. phoretica, and is
described below.
Character states defining Solenopsis are pro-
vided by Ettershank (1966), or can be derived
from the keys in Bolton's guide to ant genera
(1994). Members of the genus can usually be rec-
ognized by the following combination of character
states: 2-segmented petiole; 2-segmented anten-
nal club; propodeum lacking spines or angles; pet-
iolar node well developed; head and body shining,
sculpture restricted to setigerous punctures and
localized striae; clypeus longitudinally carinate,
with a median, apical marginal seta. The clypeal
features are lacking in S. phoretica and the spe-
cies described below.
We have designated a dealate queen as the ho-
lotype because of the apparent close relationship
between this species and S. phoretica. Diagnosis
of the new species must be by reference to charac-







Deyrup & Prusak: Inquiline Solenopsis from Dominica


ter states of queen S. phoretica, as workers of that
species are unknown.

Solenopsis enigmatica, Deyrup and Prusak
new species

Diagnosis of Dealate Female (Fig. 1). Distin-
guished from most other Solenopsis by the form of
the mandibles, which are falcate, with the teeth
not in an oblique series, as normal in species of
Solenopsis; the basal angle is strongly developed
and weakly bidentate, the concave inner margin
with a low, median double tooth; S. phoretica
lacks this median double tooth.
Description of Holotype Dealate Female. Fea-
tures visible in lateral view, described from left
side. Measurements in mm. Total length (length
of head excluding mandibles + length of meso-
soma + length of petiole + length of postpetiole +
length of gaster): 3.92; head length: 0.60; head
width at rear margins of eyes in frontal view: 0.62;
length of mesosoma: 1.20; length of petiole: 0.37;
length of postpetiole: 0.20; length of gaster: 1.55.
Color: yellowish brown, ocellar triangle dark
brown, appendages yellow. Head: smooth, shin-
ing, sparsely covered with setigerous punctures
separated by 2-8 times the width of a puncture in
frontal area, 2-4 times the width of a puncture on
sides, setae suberect, directed posteriorly in fron-


tal area, elsewhere directed anteriorly; ocelli not
enlarged, each ocellus about the width of antenna
scape near base; malar distance about half (4/7)
length of eye; mandibles elongate, a little less
than half the length of the head at midline; man-
dible with basal angle strongly developed, biden-
tate; inner margin of mandible strongly concave
distal to basal angle, with a low, median, marginal
double tooth, the proximal cusp blunt but conspic-
uous, the distal cusp reduced to a low ridge;
clypeus declivitous, concave, without carinae,
with 4 subapical elongate setae; antennae 10-seg-
mented, scapes reaching outer corner of head in
frontal view, antennal club 2-segmented, club
about as long as remainder of funiculus. Meso-
soma: smooth and shining, with sparse setigerous
punctures on pronotum and near margins of
mesonotum, mesopleura, sides of propodeum;
katepisternum with sparse setigerous punctures;
disc of mesonotum and declivity of propodeum not
punctate; propodeum evenly declivitous in lateral
view; legs smooth, shining, with sparse, strong,
semidecumbent, curved, distally directed hairs;
hind basitarsus longer than hind tibia; a dense,
coarse, ventral brush of hairs on distal half of
front basitarsus. Petiole: peduncle short, less than
0.25 length of base of petiole in lateral view; node
of petiole in lateral view triangular, apex broadly
and smoothly rounded, in posterior view semicir-


Fig. 1. Solenopsis enigmatica, dealate female reproductive, length of specimen 3.92 mm.


\U






Florida Entomologist 91(1)


cular; ventral process narrowly expanded, with a
small ventral projection that is like a low ridge
rather than a tooth. Postpetiole: low and rounded
above in lateral view, in posterior view about 1.5
times as wide as long. Gaster: in dorsal view first
tergite with prominent, rounded anterior corners,
projecting forward from midline; first gastral terg-
ite and sternite each with a broad, median, basal
concavity; first tergite with sparse, long, suberect,
posteriorly-directed, hairs that are generally dis-
tributed; tergites 2-4 smooth, each with an irreg-
ular row of large, suberect, subapical hairs.
Type Locality and Associated Information.
Collecting data on labels (3) of holotype: DOMIN-
ICA, W.I., Pont Casse, 30 April 2006, M., N., L.
Deyrup; Trail to Trois Pitons, in nest of Pheidole
antillana in rotten log; rainforest near base of
trail, N1522.80', W6120.46'.
Diagnosis of Worker (Fig. 2). Distinguished
from other Solenopsis workers by clypeal mor-
phology: clypeus lacking carinae, in lateral view
rounded and strongly declivitous. Pale yellow, an-
tennal scapes short, in frontal view failing to
reach occipital margin of head by a distance about
equal to the combined length of the first 4 seg-
ments of the funicle. If S. phoretica produces
workers, they might be similar to those of enig-
matica, so this diagnosis may not be definitive.
Description of Paratype Worker. Measure-
ments in mm. Total length (length of head exclud-


ing mandibles + length of mesosoma + length of
petiole + length of postpetiole + length of gaster):
2.27; head length: 0.50; head width at rear mar-
gins of eyes in frontal view: 0.45; length of mesos-
oma: 0.60; length of petiole: 0.20; length of postpe-
tiole: 0.12; length of gaster: 1.55. Color: pale yel-
low, eyes black. Head: smooth, shining, with scat-
tered setigerous punctures, including a series of 4
large, posteriorly-directed, suberect, slightly con-
vergent setae on each side of frontal area, and sev-
eral small, decumbent, convergent setae on each
side of frontal area; eye composed of a single,
large, dark facet; mandibles unlike those of queen,
more typical of workers of other small Solenopsis
species: apical tooth long and sharp, remaining 3
teeth small, sharp, in a strongly oblique series,
with a long, toothless proximal inner margin;
clypeus without carinae, convex in lateral view,
with four subapical elongate setae and a long me-
dian apical seta; antennae 10-segmented, scapes
in frontal view failing to reach occipital margin by
a distance about equal to the first 4 segments of
the funicle; antennal club 2-segmented. Mesos-
oma smooth, shining, pronotum with 3 large,
semierect, posteriorly-directed setae on each side,
and 1 smaller, semierect, anteriorly-directed seta
on each side at posterior margin of pronotum; pro-
podeal spiracle large, as in Fig. 2; legs smooth,
shining, with sparse, strong, semidecumbent, dis-
tally-directed hairs; hind basitarsus about the


'N


N"s,


Fig. 2. Solenopsis enigmatica, worker, length of specimen 2.27 mm.


March 2008


.1 1


el*cp






Deyrup & Prusak: Inquiline Solenopsis from Dominica


length of hind tibia. Petiole: apex of node in poste-
rior view somewhat flattened; node with two long,
posteriorly-directed setae on each side near apex;
ventral process a low, triangular tooth, somewhat
rounded apically. Postpetiole: low and rounded
above in lateral view; in dorsal view 5/7 as long as
wide. Gaster: first tergite with sparse, long,
suberect, posteriorly-directed hairs that are gen-
erally distributed; tergites 2-4 smooth each with
an irregular row of large, suberect, subapical
hairs; sting slightly extruded.
Type locality and associated information as in
holotype female.
Additional Paratype Material. Two workers,
one a pharate adult in pupal skin, associated with
the holotype female. One dealate queen: collect-
ing data as on labels: DOMINICA, W.I., Cochrane,
west of Morne Macaque, 29 April 2006. Z. Prusak.
Middleham Falls Trail, in nest of Pheidole antil-
lana in rotten log. 1520.852'N, 6120.698'W.
All specimens were collected in Dominica rain
forest habitat as defined by Lack et al. (1998),
with evergreen shrubs, canopy trees and abun-
dant epiphytes.
Holotype and other type material to be depos-
ited in the Museum of Comparative Zoology, Har-
vard University, Cambridge, MA.
Etymology: from aenigma (Latin), meaning
"mystery," referring to the many unknown aspects
of the natural history of this unusual Solenopsis.


DISCUSSION
There is a striking resemblance between the
queens of enigmatica and phoretica (Fig. 1, Fig. 3).
With only one specimen of phoretica and two of
enigmatica, little can be said about the variation in
either species. It seems unlikely, however, that
these specimens represent a single, widespread,
variable species. The differences in mandibular
structure are probably functionally significant,
considering that the specimen of phoretica was
found with her mandibles locked around the peti-
olar peduncle of the host queen. Inquiline ants tend
to be host-specific, exploiting a single host, or a few
very closely related hosts (Hdlldobler & Wilson
1990). Pheidole antillana Forel is in the tristis spe-
cies group of Pheidole, dentata in the fallax group,
and the two species are not closely related (Wilson
2003). It also seems more likely that these speci-
mens represent 2 rare, localized species, rather
than a widely distributed species that has never
been found anywhere but Florida and Dominica.
The S. phoretica-enigmatica group is known
from only 3 queens and a few associated workers,
but all 3 were apparent inquilines in the nest of
Pheidole species, and we are assuming that this is
a normal association. It is rare for an inquiline
ant to be so distantly related to its host, but there
is a relevant example in Oxyepoecus, a genus re-
lated to Solenopsis, with hosts in both Pheidole


A/


A


Fig. 3. Solenopsis phoretica, dealate female reproductive, length of specimen 3.03 mm.







Florida Entomologist 91(1)


and Solenopsis (H6lldobler & Wilson 1990). We
are not suggesting that there is any reason to
think that phoretica and enigmatica could be
transferred to Oxyepoecus, or that they represent
some sort of transition between Solenopsis and
Oxyepoecus. Several species of small Solenopsis
may live in nests adjacent to those of other ants,
which they exploit in what one might call a peri-
inquiline way (Hlldobler & Wilson 1990), and it
could be that the phoretica-enigmatica lineage
took such a relationship a few steps further.
The exact nature of the relationship between
S. enigmatica and its host is unknown. It is rea-
sonable to speculate that queen enigmatica spend
some time in close association with the host
queen, as enigmatica has the elongate mandibles
and concave first gastral tergite found in phoret-
ica. No queen Pheidole was found in either of the
2 colonies that contained enigmatica, but it is pos-
sible that the host queens were overlooked. The
presence of 3 workers associated with 1 queen
enigmatica is consistent with the hypothesis that
enigmatica is a temporary nest parasite, but no
mature colony has been found. Worker enigmatica
are conspicuously larger than the other 3 species
of yellow Solenopsis that we found on Dominica,
and it is unlikely that we would have discarded a
colony of enigmatica, mistaking it for one of the
common little yellow Solenopsis. Parasitic ants in
general are notoriously rare. The abundance of
another parasitic Solenopsis, S. daguerrei (Sant-
schi) has been studied by Calcaterra et al. (2000).
With 4,131 potential host colonies examined, par-
asitization rates were 3.9%. If this degree of rar-
ity is at all typical of parasitic Solenopsis, we were
fortunate to find 2 parasitized colonies during the
short time we were in Dominica.
It is highly unlikely that the phoretica-enig-
matica lineage of Solenopis is confined to the is-
land of Dominica and Alachua County in Florida.
One possibility is that members of this group oc-
cur throughout the range of Pheidole in the New
World, but have escaped notice because they are
rare and host-specific. It is also possible that this
group of inquilines can only succeed in communi-
ties in which a few species of Pheidole are espe-
cially abundant, with persistent and accessible
colonies. This might favor the success of inquilines
on islands with relatively low Pheidole diversity,
and near the edges of the range of Pheidole. The
relentless raiding of Pheidole nests by army ants
in the humid Neotropics would seem to decrease
the effective resource base for inquilines.
The potential host range for S. enigmatica on
Dominica is probably limited. The species most
similar to P. antillana is P laudatana Wilson, a
slightly smaller member of the tristis group that is
common on Dominica, but not known from other
islands. Both species are common in primary for-
est on Dominica. Pheidole antillana nests in rotten
sticks and logs on the forest floor, while colonies of


laudatana nest in clay soil and have a small nest
opening. It seems probable that antillana is
more vulnerable to inquilines than laudatana. If
it turns out that S. enigmatica is a host-specific
inquiline, it must have a restricted distribution,
as P antillana is known only from St. Vincent,
Grenada and Dominica. We found antillana com-
mon in the extensive forest reserves on Domin-
ica, but absent from disturbed areas. Other is-
lands of the Lesser Antilles have less extensive
forest reserves, in some cases only small frag-
ments. It is too soon too speculate about the rar-
ity of S. enigmatica, but its conservation status
is one of several interesting questions pertaining
to the species.

ACKNOWLEDGMENTS

We thank Arlington James, Forest Officer from the
Forestry, Wildlife and Parks Division of the Dominica
Ministry of Agriculture and the Environment for pro-
viding research permits and for sharing his remarkable
natural history expertise. We thank Nancy Osler, Man-
aging Director of the Archbold Tropical Research and
Education Center for her hospitality and for offering
her invaluable logistical support during our expedition
to Dominica. We thank James Wetterer, who supplied
funds for the expedition under a grant from the Na-
tional Science Foundation to survey the ants of the east-
ern Caribbean. We thank Nancy and Leif Deyrup for
assisting in collecting ants throughout our stay in Do-
minica. We gratefully acknowledge the Government of
Dominica for protecting and managing the amazing
natural areas that serve as refuges for this species and
thousands of other interesting animals.

LITERATURE CITED

BOLTON, B. 1994. Identification Guide to the Ant Gen-
era of the World. Harvard University Press, Cam-
bridge, MA. 222 pp.
BOLTON, B. 1995. A New General Catalog of the Ants of
the World. Harvard University Press, Cambridge,
MA. 504 pp.
CALCATERRA, L. A., J. A. BRIANO, AND D. F. WILLIAMS.
2000. New host for the parasitic ant Solenopsis da-
guerrei (Hymenoptera: Formicidae) in Argentina.
Florida Entomol. 83: 363-365.
DAVIS, L. R., AND M. DEYRUP. 2006. Solenopsis phoret-
ica, a new species of apparently parasitic ant from
Florida (Hymenoptera: Formicidae). Florida Ento-
mol. 89: 141-143.
ETTERSHANK, G. 1966. A generic revision of the world
Myrmicinae related to Solenopsis and Pheidologeton
(Hymenoptera: Formicidae). Australian J. Zool. 14:
73-171.
HOLLDOBLER, B., AND E. O. WILSON. 1990. The Ants.
Harvard University Press, Cambridge, MA. 732 pp.
LACK, A. J., C. WHITFOORD, P. G. H. EVANS, AND A.
JAMES. 1998. Dominica: Nature Island of the Carib-
bean. 5: Illustrated Flora. Ministry of Tourism, Do-
minica. 88 pp. + 76 pp. illustrations.
WILSON, E. 0. 2003. Pheidole in the New World: a Dom-
inant, Hyperdiverse Ant Genus. Harvard University
Press, Cambridge, MA. 794 pp.


March 2008







Jenkins et al.: Entomopathogenic Nematodes vs. Diaprepes abbreviatus



EFFICACY OF ENTOMOPATHOGENIC NEMATODES VERSUS
DIAPREPES ABBREVIATUS (COLEOPTERA: CURCULIONIDAE) LARVAE
IN A HIGH CLAY-CONTENT OXISOL SOIL: GREENHOUSE TRIALS
WITH POTTED LITCHI CHINENSIS

DAVID A. JENKINS', DAVID SHAPIRO-ILAN2 AND RICARDO GOENAGA1
1USDA-ARS, Tropical Agriculture Research Station, 2200 Ave. P. A. Campos, Mayaguez, PR 00680-5470

2USDA-ARS, Southeastern Fruit and Tree Nut Research Lab, Byron, GA 31008

ABSTRACT
In a previous study, laboratory trials indicated that 9 strains and species of entomopatho-
genic nematodes (EPNs) were pathogenic against larvae of Diaprepes abbreviatus in an Ox-
isol from Puerto Rico. In this study we tested the efficacy of 5 species/strains of EPN in an
Oxisol under greenhouse conditions. The nematodes were applied at 100 infective juveniles
per cm2 to 19-L pots containing a high clay-content Oxisol (69% clay) and 3 seedlings of Lit-
chi chinensis. All treatments significantly reduced the mean proportion ofD. abbreviatus lar-
vae surviving (ranging from 0 to 36%) compared to survival in untreated controls (ranging
from 80 to 86%). This suggests that EPNs might be suitable to play a role in integrated pest
management strategies against D. abbreviatus in tropical soils with high clay content.

Key Words: Litchi chinensis, Steinernema riobrave, Heterorhabditis megidis, Oxisol

RESUME

Estudios recientes en el laboratorio demostraron que nueve species de nematodos entomo-
patog6nicos (EPN) causaron patogenicidad en larvas de Diaprepes abbreviatus en un suelo
Oxisol en Puerto Rico. En este studio se determine la eficacia de cinco species de EPN en
un Oxisol bajo condiciones de invernadero. Se aplicaron 100 nematodos juveniles por cm2 en
tiestos de 19 litros conteniendo un suelo Oxisol (69% arcilla) y tres plantulas de Litchi chin-
ensis. Todos los tratamientos redujeron significativamente la sobrevivencia de larvas de
D. abbreviatus en relaci6n al tratamiento control (porciento de sobrevivencia para todos los
tratamientos vario de 0 a 36 6 EEM). Esto sugiere que EPN's pueden jugar un papel im-
portante en el manejo integrado de plagas, particularmente artr6podos en suelos tropicales
con alto contenido de arcilla.


Translation provided by the authors.


Diaprepes abbreviatus (L.) (Coleoptera: Curcu-
lionidae) is a key pest of a wide variety of crops in
Puerto Rico (Martorell 1976; O'Brien & Wibmer
1982). Adults feed on the foliage of fruit trees and
other hosts (Simpson et al. 1996) and the larvae at-
tack the roots, reducing yield, allowing the ingress
of pathogenic organisms, or directly killing the
tree by removing cortex from the roots, especially
in seedlings (Knapp et al. 2000; Nigg et al. 2001;
Quintela et al. 1998). Litchi chinensis Sonn. (Sap-
indaceae) is a tropical/subtropical fruit tree native
to southern China (Morton 1987). Because of its
marketability, some growers in Puerto Rico are at-
tempting to cultivate orchards ofL. chinensis, but
there are currently no recommendations for deal-
ing with the pests associated with this fruit tree in
Puerto Rico, including D. abbreviatus. Recent sur-
veys in Puerto Rico indicate that L. chinensis is a
suitable host for D. abbreviatus and can suffer sig-
nificant damage from the root-feeding larvae of
this pest (Jenkins, unpublished data).


Entomopathogenic nematodes (EPNs) have a
mutualistic association with bacteria found in
their intestine and the nematodes are obligate
parasites of insects (Poinar 1990). The infective ju-
veniles move through the soil, either actively
searching for suitable hosts or relying on the host
to come to them (Lewis et al. 2006). The infective
juveniles enter the host through natural openings,
such as spiracles, the anus, or the mouth (Poinar
1990). Once inside the host, the nematodes release
the mutualistic bacteria, which kill the host
within 48 h (Poinar 1990). Two or 3 generations of
nematodes are completed within the host cadaver
before infective juveniles are released into the soil
to search out new hosts (Poinar 1990).
Entomopathogenic nematodes have had a de-
monstrable effect against many soil-borne insect
pests, including D. abbreviatus (McCoy et al.
2000; Shapiro-Ilan et al. 2002, 2005). However, it
is generally thought that soils of high clay con-
tent, such as those common in Puerto Rico, reduce







Florida Entomologist 91(1)


the efficacy of EPNs as biocontrol agents of soil-
borne insect pests (Duncan et al. 2001; McCoy et
al. 2002). Indeed, several studies have indicated
that nematode dispersal is hampered in soils of
high clay-content (Georgis & Poinar 1983; Bar-
bercheck & Kaya 1991; Portillo-Aguilar et al.
1999). However, virulence and persistence of
Steinernema riobrave (Cabanillas, Poinar & Raul-
ston) and Heterorhabditis bacteriophora Poinar
appeared to improve in a higher clay-content En-
tisol when compared to a sandy Spodosol and a
sandy Entisol (Shapiro et al. 2000). Furthermore,
recent laboratory trials indicated that some EPNs
were efficacious in high clay-content Oxisols
found in Puerto Rico (Jenkins et al. 2007).
The objective of this study was to assess the ef-
ficacy of 5 species/strains of EPNs under green-
house conditions in a larger volume of high clay-
content soil than had been assayed in earlier lab-
oratory trials. This would more rigorously test the
EPN's ability to locate their host in an experiment
that more closely resembles a nursery or an or-
chard setting.

MATERIALS AND METHODS

Soil (Oxisol, Coto clay, clayey, kaolinitc isohy-
poerthermic Typic Hapludox) was collected from
the USDA-ARS Experiment Station in Isabela,
PR. The soil composition, determined by the hy-
drometer method, was 29.55% sand, 13.92% silt,
and 60.88% clay and had a pH of 8.07. The propor-
tion of total nitrogen in the soil, determined by
the micro-Kjeldahl method, was 0.20. The concen-
tration of other critical elements in the soil was
determined by atomic absorption spectroscopy
(K, Ca, Mg, Cu, Fe, Mn, and Zn) or the Bray II
Method (P) and were as follows: P = 35 pg/g; K =
170 pg/g; Ca = 2,842 pg/g; Mg = 61 pg/g; Cu = not
detected; Fe = not detected; Mn = 123 pg/g; and
Zn = 4 pg/g.
Soil (22-23 kg) was placed into 19-L buckets
(bucket dimensions = mouth diameter of 29 cm
and depth of 36 cm). Three L. chinensis seedlings
were planted in the soil in each bucket. Ten 9th
through 11th instars of D. abbreviatus, obtained
from the Florida Division of Plant Industry, were
placed in 10 holes, each 10 cm deep, made with an
auger around the 3 L. chinensis seedlings. Holes
were manually filled with soil after placement of
larvae.
Five strains/species of EPNs were assayed
against larvae of D. abbreviatus: S. riobrave
(strains 355, 7-12, and TP), S. diaprepesi Nguyen
& Duncan, and Heterorhabditis megidis Poinar,
Jackson, & Klein (UK211 strain). Prior to the as-
says, nematodes were reared in last instars of the
greater wax moth, Galleria mellonella (L.) (Lepi-
doptera: Pyralidae). All nematodes were reared at
25 + 1C according to procedures described in
Kaya & Stock (1997). After harvesting nematodes


from G. mellonella, the nematodes were stored in
tap water at 13C (Kaya & Stock 1997) for up to 1
week prior to the assays. Viability of all nema-
todes was >90% at the time of application.
Nematodes were applied 24 h after placement
of D. abbreviatus larvae at the rate of 100 infec-
tive juveniles per cm2 in 1 L of water (surface area
of soil = 660 cm2 x 100 infective juveniles/cm2 =
66,000 infective juveniles / bucket). Control buck-
ets were treated with 1 L of water poured evenly
over the soil surface. Buckets were then placed in
a greenhouse at the USDA-ARS Tropical Agricul-
ture Research Station in Mayaguez, PR (mean
temperature 25C, RH 74%). Each treatment was
replicated 5 times and the entire experiment was
repeated in a second trial a month later. After 14
d, the experimental units were dismantled and
the number of living D. abbreviatus larvae was re-
corded in each bucket. Dead larvae were in-
spected under the microscope to confirm that
death was caused by nematodes. Nematodes
reared from cadavers were placed in a Petri-dish
with 5 G. mellonella larvae and monitored to con-
firm pathogenicity.
Analysis of variance (PROC GLM) and Stu-
dent-Newman-Keuls multiple range test (SAS
2003) were used to analyze the effect of EPN spe-
cies/strain on the survival ofD. abbreviatus lar-
vae. Statistical analyses were conducted on arc-
sine transformed data (percent surviving).

RESULTS

Analysis indicated that survival of D. abbre-
viatus larvae was reduced by EPN (for trial 1, F =
20.24, P < 0.0001, df = 1,5; for trial 2, F = 45.11, P
< 0.0001, df = 1,5) (Table 1). We detected no sur-
viving larvae in the buckets receiving S. riobrave
(TP strain) in Trial 1 or in buckets receiving S. ri-
obrave (355 strain) in both trials (Table 1). In the
first trial no species/strains of EPN could be sta-
tistically differentiated based on the proportion of
surviving D. abbreviatus larvae (arcsine trans-
formed), but in the second trial all S. riobrave
strains caused significantly lower larval D. abbre-
viatus survivorship than did S. diaprepesi or H.
megidis (Table 1).

DISCUSSION

Our results demonstrate that EPNs can pro-
vide high levels ofD. abbreviatus suppression in
an Oxisol under greenhouse conditions. Ento-
mopathogenic nematodes have been reported to
control D. abbreviatus under greenhouse condi-
tions previously (Shapiro & McCoy 2000a; Sha-
piro-Ilan et al. 2003), however, this is the first re-
port of efficacy in potted plants in a high clay-con-
tent soil. Thus, it is clear that, under the condi-
tions of this study, the Oxisol's texture is not a
significant impediment to nematode movement


March 2008







Jenkins et al.: Entomopathogenic Nematodes vs. Diaprepes abbreviatus


TABLE 1. PROPORTION OF DIAPREPES ABBREVIATUS LARVAE SURVIVING AFTER 14 D EXPOSURE TO NEMATODES. THE
NEMATODES WERE APPLIED TO POTTED LITCHI CHINENSIS HELD IN 19 L OF AN OXISOL FROM PUERTO RICO.

Proportion surviving SEM"

Treatment: Nematode species (strain) Trial 1 Trial 2

Control 0.80 0.07 a 0.86 0.03 a
Steinernema diaprepesi 0.32 + 0.10 b 0.36 0.06 b
S. riobrave (7-12) 0.26 0.07 b 0.12 0.05 c
S. riobrave (355) 0.00 0.00 b 0.00 0.00 c
S. riobrave (TP) 0.00 0.00 b 0.02 0.02 c
Heterorhabditis megidis (UK211) 0.24 0.07 b 0.30 + 0.12 b

"Means followed by the same letter are not significantly different (Student-Newman-Keuls multiple range testP < 0.05: For trial
1, F = 20.24, P = <0.0001, df= 1, 5; For trial 2, F = 45.11, P< 0.0001, df= 1, 5). Each treatment was replicated 5 times and analysis
was performed on arcsine transformed data.


and infection. It may be argued that since we only
placed the D. abbreviatus larvae 10 cm deep, the
nematodes did not have far to travel. However, in
every case larvae were found in the lower half of
the soil column (18 cm or deeper) and more than
85% percent of the larvae were found within 10
cm of the bottom of the bucket.
Previous assays of EPNs in Puerto Rico used
large numbers of infective juveniles (>1000/cm3 of
soil) and achieved only minimal control ofD. ab-
breviatus (<50% survival) (Roman & Figueroa
1985; Figueroa & Roman 1990). Many previous
evaluations in Puerto Rico were restricted to
Steinernema carpocapsae (=Neoaplectana carpoc-
apsae) (Roman & Beavers 1983; Roman &
Figueroa 1985), a nematode that tends to inhabit
the surface of the soil and would have little chance
of encountering root-feeding grubs that tend to be
found deeper in the soil (Lewis et al. 2006).
Although the volume and weight of soil used in
this study (19 L, 22 kg) was vastly larger than in
a previously conducted laboratory assay (0.087 L,
0.4 kg), the species/strains of EPNs performed
similarly in both studies (Jenkins et al. 2007). The
mean proportion of larval D. abbreviatus surviv-
ing were remarkably similar in both assays for
treatments with S. diaprepesi (0.32-0.36 for the
current study and 0.33 for Jenkins et al. 2007)
and H. megidis (0.24-0.30 for the current study
and 0.25 for Jenkins et al. 2007). This is some-
what unexpected given the larger volume of soil
used in the current experiments, but we do note
that the earlier laboratory assay did use a lower
rate of EPNs (40 infective juveniles per cm2) (Jen-
kins et al. 2007). The 7-12 strain ofS. riobrave ap-
peared to perform better in the laboratory assay
(mean proportion surviving = 0; Jenkins et al.
2007) than in the current study (mean proportion
surviving = 0.12-0.26) whereas the 355-strain of
S. riobrave appeared to perform better in the cur-
rent study (mean proportion surviving = 0 for
both trials) than in the laboratory assay (mean
proportion surviving = 0.08; Jenkins et al. 2007).


Treatment with the TP-strain of S. riobrave re-
sulted in 0 percent survival in both the current
and the laboratory study (Jenkins et al. 2007).
This study provides evidence (Trial 2) that, un-
der the conditions tested, performances of S. rio-
brave strains are superior to those of H. megidis
and S. diaprepesi. Superior virulence of S. rio-
brave has been observed previously in sandy soil
(Shapiro & McCoy 2000b). In a laboratory study
Stuart et al. (2004) observed superior virulence in
the 7-12- and TP-strains ofS. riobrave relative to
the 355-strain, but no differences were observed
among S. riobrave strains in our study. Nor was
any difference among these strains observed in
Jenkins et al. (2007). Possibly the discrepancy is
due to different soil types (a sandy soil was used
in the study of Stuart et al. 2004). The superior ef-
ficacy of S. riobrave indicates that this may be the
nematode of choice for control ofD. abbreviatus in
an Oxisol. However, it is conceivable that other
characteristics, such as persistence, could factor
into the choice of nematode to use, e.g., S. di-
aprepesi is known to be highly persistent relative
to S. riobrave, at least in its native soil (Duncan et
al. 2003).
In summary, all 5 species/strains of EPNs as-
sayed reduced the proportion of D. abbreviatus
larvae surviving compared with the control treat-
ment. The second trial indicated that all strains of
S. riobrave were more efficacious than the other
EPN species assayed. Field trials are needed to
assess the efficacy of these EPNs under orchard
conditions.

ACKNOWLEDGMENTS

We thank Suzanne Fraser at the Florida Division of
Plant Industry for providing us with Diaprepes abbre-
viatus larvae. We also thank Elkin Vargas for tremen-
dous field and lab work and Ulises Chardon for
analyzing the soil samples. Finally, we thank Robin Stu-
art and Wayne Gardner for reviewing earlier versions of
this manuscript.











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Florida Entomologist 91(1)







Nietschke et al.: Potential for Scirtothrips dorsalis Establishment in US


CLIMATOLOGICAL POTENTIAL FOR SCIRTOTHRIPS DORSALIS
(THYSANOPTERA: THRIPIDAE) ESTABLISHMENT IN THE UNITED STATES

BRETT S. NIETSCHKE1, DANIEL M. BORCHERT2, ROGER D. MAGAREY1'2'4 AND MATTHEW A. CIOMPERLIK3
'Center for Integrated Pest Management, North Carolina State University,
1730 Varsity Drive, Suite 110 Raleigh, NC 27606

2United States Department of Agriculture, Center for Plant Health Science and Technology,
1730 Varsity Drive, Suite 300/400 Raleigh, NC 27606

3United States Department of Agriculture, Center for Plant Health Science and Technology,
Pest Detection and Diagnostics Laboratory, Edinburg, TX 78539

4E-mail address: Roger.D.Magarey@aphis.usda.gov


ABSTRACT

Scirtothrips dorsalis is a serious exotic pest that has recently become established in the con-
tinental United States. It is of major concern to regulatory agencies because it has a wide
host range and high reproductive potential. A weather-based mapping tool, NAPPFAST,
was used to predict potential establishment of S. dorsalis in North America. The analysis
was based on a degree-day model and cold temperature survival of S. dorsalis. The results
demonstrated that S. dorsalis could potentially produce up to 18 generations and was likely
to survive in the southern and western coastal plains of the United States. It is concluded
that S. dorsalis is likely to be a serious economic pest in the southern United States. Addi-
tional maps and information are available at the web site (http://www.nappfast.org).

Key Words: exotic species, insect development, temperature, risk mapping, Scirtothrips dor-
salis

RESUME

Scirtothrips dorsalis es una important plaga exotica que se ha establecido recientemente
en el continent de los Estados Unidos. La presencia de este insecto es preocupante para las
agencies que se encargan de la protection fitosanitaria debido a que esta especie tiene una
lista amplia de plants hospederas y un alto potential reproductive. Utilizamos el program
de mapeo NAPPFAST (que se basa en temperature) para predecir las posibles areas de es-
tablecimiento de S. dorsalis en Norte America. El analysis se baso en un modelo de grades
dia y en la supervivencia de S. dorsalis a temperatures bajas. Los resultados demuestran
que S. Dorsalis potencialmente podria producer hasta 18 generaciones por aio y que es pro-
bable que sobreviva en las planicies costeras del sur y el oeste de los Estados Unidos. Con-
cluimos que S. dorsalisprobablemente se convertira en una plaga economic seria para el
sur de los Estados Unidos.


Translation provided by the authors.


The chilli thrips, Scirtothrips dorsalis Hood
(Thysanoptera: Thripidae) is a serious exotic pest
that has recently become established in the conti-
nental United States. It is a highly polyphagous
species with over 100 plant species cited as host
plants (Meissner et al. 2005). Scirtothrips dorsa-
lis occurs throughout Asia, Australasia, and the
Pacific Islands (CABI 2005) and in 2003 was in-
tercepted at the port of Miami, Florida, on a ship-
ment of peppers (Capsicum sp.) originating from
the Caribbean island of St. Vincent (Skarlinsky
2003). It was subsequently confirmed in St. Vin-
cent, St. Lucia (Skarlinsky 2003; Ciomperlik &
Seal 2004), Barbados (Ciomperlik et al. 2005a),


Trinidad and Tobago, Puerto Rico (Ciomperlik
unpublished data), and in South America in Suri-
name (Ciomperlik et al. 2005b) and Venezuela
(M. Quiros, pers. comm.). In late 2005, S. dorsalis
was reported in Florida (Hodges et al. 2005) and
has been detected 70 times in 16 Florida counties
(Holtz 2006). In 2004, APHIS began a compre-
hensive risk assessment of the potential intro-
duction and establishment of S. dorsalis (Meiss-
ner et al. 2005).
Scirtothrips dorsalis is estimated to produce
up to 8 generations annually in Japan (Tatara
1994); however, its generational potential in the
United States is unknown. Although S. dorsalis







Florida Entomologist 91(1)


has colonized parts of Florida, the areas where it
could potentially survive and establish remain
undefined. A predicted establishment map was
developed by Venette & Davis (2004) based on a
biome matching technique (Olsen et al. 2001).
The study predicts that potential establishment
in the eastern United States would not include
the coastal plain, with the exception of a small
area of southern Florida. On the west coast, po-
tential establishment was limited to the Wil-
lamette Valley in Oregon.
The biome approach used by Venette & Davis
(2004) is an example of an inductive risk mapping
technique where the predicted distribution is
based on a climate or habitat match (Baker 2002).
Inductive risk maps based on climate and host
distribution have been used widely to predict po-
tential pest establishment (Sutherst & Maywald
1985; McKenney et al. 2003; Hoddle 2004). Risk
maps also are created with deductive techniques
that use experimental data to create biological
models that predict a pathogen's distribution
from weather or climate data (Baker 2002). One
deductive approach useful for predicting estab-
lishment of exotic insect pests is phenology mod-
els (Baker 1991; Jarvis & Baker 2001; Baker
2002). Another approach is to exclude areas
where cold or hot temperatures result in pest
mortality (Magarey et al. 2007). The comparison
of deductive and inductive approaches for the
same pest provides additional evidence for deci-
sion makers.
Recently, site-specific weather technologies
have made it easier to apply pest phenology and
weather-based risk models to risk prediction on a
regional or national scale. The technology uses
spatial interpolations and numerical models to
create simulated observations (Russo 1999; Ma-
garey et al. 2001). Site-specific weather technolo-
gies have successfully been used to deploy pheno-
logical models at the scale of individual farms or
at a regional scale for many insects including, ap-
ple (Malus domestic) pests, gypsy moth (Lyman-
tria dispar), root weevils (Diaprepes abbreviatus),
Monarch butterfly (Danaus plexippus), and Euro-
pean corn borer (Ostrinia nubilalis) (Russo et al.
1993; Felland et al. 1997; Dively et al. 2004; Dille-
hay et al. 2005; Lapointe et al. 2007). In this
study, a web-based modeling system was used to
create potential weather-based pest establish-
ment maps in the United States for S. dorsalis.

METHODS

Risk maps for S. dorsalis were created by using
the standardized procedure for 50 exotic pests
listed as priorities by the Cooperative Agricul-
tural Pest Survey program (Borchert & Margo-
sian, unpublished). Climate risk maps were pro-
duced based on the North Carolina State Univer-
sity-APHIS Plant Pest Forecast (NAPPFAST)


modeling system (Borchert & Magarey 2005;
Magarey et al. 2007). The system was built and
maintained by a commercial weather company
(ZedX, Inc., Bellefonte, PA) with experience in
pest modeling and site-specific weather data
(Russo 1999). The NAPPFAST system links daily
climate and historical weather data with biologi-
cal models that contain a series of interactive 'fill-
in-the-blanks' templates (Borchert & Magarey
2005). The model template was based on one de-
veloped for European corn borer (Dillehay et al.
2005) that uses daily weather and climate data
from approximately 2000 weather stations across
North America. Individual station values are in-
terpolated to a 10 km2 by using the Barnes
method (Barnes 1964). The NAPPFAST system
has been validated for Japanese beetle (Popillia
japonica) (Magarey et al. 2005), Diaprepes abbre-
viatus (Lapointe et al. 2007) and numerous inter-
nal APHIS pests risk assessments (Magarey et al.
2005). As NAPPFAST lacks international
weather data (outside of North America), valida-
tion of the model was limited to the Caribbean.
Based upon the insect development template
in NAPPFAST, generation potential maps were
created for S. dorsalis from 10 years (1994-2004)
of the North American climate database. To deter-
mine the potential number of generations S. dor-
salis could complete in a year, the developmental
model used parameters of 9.7C as the base devel-
opmental temperature and cumulative degree-
day (DD) requirement from oviposition to oviposi-
tion of 281C DD (Tatara 1994). These require-
ments were similar to those Shibao (1996) used
for S. dorsalis on grape (Vitis vinifera). To illus-
trate the influence of climate on generation poten-
tial, probability maps were developed displaying
the frequency of occurrence of 1 to 5 generations.
Although S. dorsalis will most likely develop more
than 5 generations in many areas of the United
States, it was assumed that 5 generations repre-
sented the biological impact sufficiently. Data
which occurred less than 2 out of 10 years were
excluded from the maps and the remaining data
reclassified (with ArcGIS 8.3, ESRI, Redlands
USA) into a single representative class to demon-
strate the generational potential of S. dorsalis.
Ten-year probability maps for generations 1 to 5
were added and divided by 5 to maintain a 10-
class scale. A value of 1 represents low occurrence
of multiple S. dorsalis generations, while a value
of 10 indicates S. dorsalis has the degree-days re-
quired to complete 5 generations.
To define areas in the United States where S.
dorsalis may potentially establish, maps showing
a cold temperature exclusion boundary were cre-
ated with the 10-year North American climate da-
tabase in NAPPFAST. The cold temperature ex-
clusion model was developed for when the mini-
mum daily temperature reaches -4C or below for
5 or more days in a year. These parameters were


March 2008







Nietschke et al.: Potential for Scirtothrips dorsalis Establishment in US


based on a study of a similar thrips species,
Thrips palmi (McDonald et al. 2000) because the
temperature that is lethal to S. dorsalis is un-
known. McDonald et al. (2000) presented LD90
mortality lethal time data for 3 temperatures;
0C, -5C, and -10C. A threshold of-4C was used
because -10C occurs infrequently in the southern
United States and the LD90 at 0C was over 170 h.
Both S. dorsalis and T palmi occur frequently as
mixed populations in the field (M. Ciomperlik, un-
published data; Chu et al. 2006). A 10-year fre-
quency map showing the cold temperature exclu-
sion boundary was created in NAPPFAST and im-
ported into the GIS. Data were excluded from the
maps which occurred less than 8 out of 10 years
and the remaining data reclassified into a single
representative class.
Mortality of S. dorsalis at temperatures above
33C has been observed, with the mortality rate
at 100% after 3 d exposure to 38C (Tatara 1994).
However, constant high temperatures of this
magnitude and duration are not generally found
in the United States, so a high temperature exclu-
sion boundary was not included. The final climate
risk map for S. dorsalis was created by overlaying
the generation potential map with the cold tem-
perature exclusion boundary.
The density of host crops also determines
where insects may potentially establish. Host
density risk maps for the United States were cre-
ated in ArcGIS from county acreage data (USDA
NASS 2002). The analysis was restricted to the
top 30 agricultural commodities by value. Host
determination and host status (primary versus
secondary) (Table 1) was obtained from informa-
tion in the APHIS Global Pest Disease Database,
which was primarily sourced from the CABI Crop
Compendium (CABI 2005). Total primary and
secondary host acres were divided by the total
acres per county, re-classed into 10 classes based
on the classification scheme in Table 2 and com-
bined in a 2 (primary):1 (secondary) weighted
analysis. The scale of 1 to 10 describes the propor-
tion of total host acreage per county: for example
a rank of 1 indicates no host acreage, while a score
of 10 indicates that 75-100% of the acres in the
county contains suitable hosts for the pest.
A final risk map representing the influence of
both climate and host was created in the GIS. The
host risk map (Fig. 1) and the climate risk map
(Fig. 2) were multiplied by 0.34 and 0.66, respec-
tively, and added together to obtain a final risk
map (Fig. 3). These values were selected to give
greater importance to the host layer.

RESULTS

The greatest density of susceptible hosts in-
cludes the Gulf Coast of Texas, southern Florida,
the lower Mississippi valley, and the central val-
ley of California (Fig. 1). In areas where S. dorsa-


TABLE 1. HOST SPECIES FOR
(CABI 2005).


SIRTOTHRIPS DORSALIS


Host Status


Almonds (Prunus dulcis)
Apples (Malus spp.)
Asparagus (Asparagus spp.)
Barley (Hordeum spp.)
Beans (Phaseolus spp.)
Broccoli (Brassica oleracea)
Cantaloupes (Cucumis spp.)
Carrots (Daucus carota)
Celery (Apium graveolens)
Citrus (Citrus spp.)
Corn (Zea spp.)
Cotton (Gossypium spp.)
Cucumbers (Cucumis spp.)
Grapes (Vitis spp.)
Lettuce (Lactuca spp.)
Oats (Avena spp.)
Onions (Allium spp.)
Peaches (Prunus persica)
Peanuts (Arachis spp.)
Pears (Pyrus spp.)
Potatoes (Solanum spp.)
Rice (Oryza spp.)
Sorghum (Sorghum spp.)
Soybeans (Glycine spp.)
Strawberries (Fragaria spp.)
Sunflower (Helianthus spp.)
Tomatoes (Lycopersicon spp.)
Wheat (Triticum spp.)
Pine (Pinus spp.)
Other Softwood Trees
Soft Hardwood Trees
Hardwood Trees


Primary

Primary

Primary
Primary

Secondary
Primary
Secondary
Primary
Primary


Secondary
Primary
Secondary
Primary
Primary


Primary
Primary
Primary
Secondary



Primary
Primary


lis could potentially establish or has already
established, the major host crops of peppers (Cap-
sicum annum), eggplant (Solanum melongena),


TABLE 2. RECLASSIFICATION SCHEME FOR HOST PROPOR-
TION DATA.

Proportion of host acres Host reclassification
per county value

0 1
0-0.01 2
0.01-0.025 3
0.025-0.05 4
0.05-0.075 5
0.075-0.1 6
0.1-0.25 7
0.25-0.5 8
0.5-0.75 9
0.75-1 10







Nietschke et al.: Potential for Scirtothrips dorsalis Establishment in US


Lakes, but not on the coastal plain of the U.S. Ven-
ette & Ragsdale (2004) used a biome approach to
predict the distribution of soybean aphid (Aphis
glycines) in the United States Their results pro-
vided a good first estimate but did not forecast the
establishment of soybean aphid in central and
northern Illinois, the Dakotas and Nebraska. The
advantage of the Olson technique is that it is eco-
logically based rather than only using tempera-
ture as in our study. However, the Olson tech-
nique has relatively coarse resolution (Thuiller et
al. 2005).
It is our conclusion, that S. dorsalis is likely to
be a serious economic pest and may become estab-
lished throughout the Caribbean, and in many
parts of southern United States and the west coast.


ACKNOWLEDGMENTS

This work was funded by the Cooperative Agricul-
tural Pest Survey Program through a cooperative
project between the Center of Integrated Pest Manage-
ment, North Carolina State University and United
States Department of Agriculture Animal Plant Health
Inspection Service, Center for Plant Health Science and
Technology.

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Florida Entomologist 91(1)







Srinivasan et al.: Management D. citri Nymphs with Insecticides


LABORATORY AND FIELD EVALUATIONS OF SILWET L-77 AND
KINETIC ALONE AND IN COMBINATION WITH IMIDACLOPRID AND
ABAMECTIN FOR THE MANAGEMENT OF THE ASIAN CITRUS PSYLLID,
DIAPHORINA CITRI (HEMIPTERA: PSYLLIDAE)

RAJAGOPALBABU SRINIVASAN1' MARJORIE A. HOY', RAGHUWINDER SINGH1 AND MICHAEL E. ROGERS2
1Department of Entomology and Nematology, P.O. Box 110620, Building 970, Natural Area Drive,
University of Florida, Gainesville, FL 32611

2Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850

P -. i'. I' at Aberdeen Research and Extension Center, University of Idaho, Aberdeen, ID 83210
E-mail: babu@uidaho.edu


ABSTRACT

Silwet L-77, an organosilicone adjuvant, was used to enhance coverage of an entomopatho-
genic fungus in field trials conducted in a central Florida citrus research grove. The results
indicated that Silwet L-77, by itself, was toxic to nymphs of the Asian citrus psyllid, Diapho-
rina citri Kuwayama (Hemiptera: Psyllidae). Laboratory bioassays were conducted to con-
firm the toxicity of the adjuvant to eggs, nymphs, and adults of D. citri. Silwet L-77 at 0.05%
(500 ppm) killed all nymphs, but was not as effective against eggs and adults. However, Sil-
wet L-77, when combined with a reduced rate (one-tenth the lowest label rate = LLR) of im-
idacloprid, killed >90% of eggs and adults in laboratory tests. In a subsequent field trial, the
combination of Silwet L-77 and one-tenth the LLR of imidacloprid gave good control of
nymphs, but exhibited weak residual toxicity to adults when compared to imidacloprid at
the LLR. Additional trials were then conducted with Silwet L-77 and Kinetic, another orga-
nosilicone adjuvant, alone and in combination with different rates of imidacloprid or abam-
ectin using potted citrus trees in the greenhouse. Combining Silwet L-77 or Kinetic with
one-fourth or one-half the LLR of imidacloprid killed as many eggs, nymphs, or adults as the
LLR of imidacloprid. The combination of Silwet L-77 or Kinetic with one-fourth or one-half
the LLR of abamectin killed as many eggs and nymphs as the LLR, but did not control adults
as well. The results are discussed in terms of managing the Asian citrus psyllid in Florida
now that citrus greening disease is endemic.

Key Words: organosilicone adjuvants, Silwet L-77, Kinetic, Asian citrus psyllid, reduced
rates of insecticides, imidacloprid, abamectin

RESUME

El Sliwet L-77, Un adyuvante organico, de silicon, fue usado para mejorar la cobertura de un
hongo entomopat6geno en pruebas de campo realizadas en un huerto de citricos de investiga-
ci6n en el centro de la Florida. Los resultados indican que el Sliwet L-77, por si solo, fue t6xico
a las ninfas del silido asidtico de los citricos, Diaphorina citri Kuwayama (Hemiptera: Psylli-
dae). Se realizaron bioesayos de laboratorio para confirmar a toxicidad del adyuvante a los
huevos, ninfas y adults de D. citri. El Silwet L-77 en una concentration de 0.05% (500 ppm)
mat6 todas las ninfas, pero no fue efectivo contra los huevos y adults. Sin embargo, Silwet
L-77 mat6 >90% de los huevos y adults en pruebas del laboratorio cuando fue combinado con
una tasa reducida (una decima parte de la menor tasa indicada por la etiqueta = MTE) del imi-
dacloprid. En pruebas de campo subseguientes, la combinaci6n de Silwet L-77 y una d6cima
parte del MTE de imidacloprid result en un buen control de las ninfas, pero mostr6 una d6bil
toxicidad residual a los adults en comparaci6n a imidacloprid al nivel de MTE. Se realizaron
pruebas adicionales con Silwet L-77 y Kinetic, otro adyuvante organico, de silicon, solo y en
combinaci6n con diferentes tasas de imidacloprid o abamectin usando arboles de citricos sem-
brados en macetas en el invernadero. Silwet L-77 o Kinetic en combinaci6n con un cuarto o la
mitad del MTE de imidacloprid mat6 tantos huevos, ninfas o adults como la MTE de imida-
cloprid. Silwet L-77 o Kinetic en combinaci6n con un cuarto o la mitad de la MTE de abamectin
mat6 tantos huevos y ninfas como la de MTE, pero no control los adults tanto como los hue-
vos y ninfas. Los resultados estan discutidos en terminos de manejo del silido asidtico de los
citricos en Florida ahora que la enfermedad de enverdecimento es considerada end6mica.







Florida Entomologist 91(1)


Silwet L-77, an organosilicone adjuvant, was
applied together with entomopathogenic fungal
spores in a field trial during 2006 to assess the ef-
fectiveness of the fungus to manage the Asian cit-
rus psyllid, Diaphorina citri Kuwayama, in a cit-
rus grove in Florida (Hoy et al. unpublished). The
results indicated that Silwet, by itself, induced
high rates of mortality of D. citri nymphs.
A subsequent literature review indicated that
trisiloxanes, a subclass of organosilicones, include
non-ionic surfactants that have an extraordinary
ability to reduce the surface tension of water
(Witco 1997). The reduction in surface tension al-
lows water to interact with hydrophobic or waxy
surfaces and enhances the spreading of water.
These surfactants are used as agricultural spray
adjuvants to enhance the spreading of spray drop-
lets on leaves and result in increased pest control
(Pollicello et al. 1995). The review also revealed
that Silwet L-77 is toxic to arthropod pests, in-
cluding two-spotted spider mites, aphids, citrus
leafminers, tephritid fruit flies, and armyworms
(Chandler 1995; Imai et al. 1995; Purcell &
Schroeder 1996; Shapiro et al. 1998; Cowles et al.
2000; Tipping et al. 2003; Neven et al. 2006). The
mode of action or toxicity mechanisms) of Silwet
L-77 have not been identified, but Cowles et al.
(2000) hypothesized that trisiloxane surfactants
could act like hyperactive soaps, thereby permit-
ting water to infiltrate the respiratory system of
insects to disrupt essential gaseous exchange.
Besides drowning, other mechanisms could be
involved. Chandler (1995) observed mortality of
armyworm larvae upon topical application, and
these compounds are believed to interact with
nerve and cell membranes to disrupt their func-
tions (Puritch 1981).
The Asian citrus psyllid is an economically im-
portant pest because it is a vector of citrus green-
ing disease, also known as Huanglongbing, yellow
shoot or yellow dragon (Capoor et al. 1974; Aubert
1987; da Graca 1991). Greening disease is caused
by a bacterium (Alpha Proteobacterium, Rhizo-
biales, Family Rhizobiaceae, Candidatus Liberi-
bacter asiaticus Gamier) that is transmitted by
the psyllid. Greening disease is considered the
most serious citrus disease in the world and the
bacterium is listed as a select agent under the Ag-
ricultural Bioterrorism Protection Act of 2002.
Greening disease was confirmed to be in Florida
during Aug 2005, and now is widely distributed in
commercial orchards and in residential trees
(Florida Dept. of Agriculture and Consumer Ser-
vices 2006). As a result of its wide distribution
when detected, eradication efforts were not im-
plemented and the goal now is to reduce the rate
of spread of the pathogen in groves where present
and to develop long-term management methods.
The psyllid is established in Texas (French et al.
2001) and could invade other citrus-growing re-
gions in the USA (i.e., Arizona and California).


The tools available to manage D. citri and
greening disease at this time in Florida include
removing infected trees, replanting with clean
nursery stock, and attempting to suppress psyllid
populations (Stansly & Rogers 2006; Rogers &
Timmer 2007). Insecticides, such as imidacloprid
and abamectin, are being applied to suppress
psyllid populations but the required multiple ap-
plications (up to 6-8) are expensive, disruptive to
natural enemies, and may lead to the develop-
ment of insecticide resistance in the psyllid. With
up to 6-8 sprays a year predicted to be used to sup-
press psyllid populations in Florida, at least until
other greening disease management methods are
developed, the costs will be substantial in both
economic and ecological terms. Thus, there is a
need for citrus growers to suppress psyllids in the
least expensive, yet most effective, manner possi-
ble. Because Silwet L-77, applied at the rate of
0.05% would cost approximately $2.00 per acre
(0.4 ha), the use of organosilicone adjuvants as
substitutes for chemical pesticides or as adju-
vants to allow use of lower rates of such pesticides
could result in substantial savings in managing
psyllid populations.
In order to explore this possibility, laboratory,
greenhouse, and field experiments were conducted
with Silwet L-77 and another organosilicone adju-
vant, Kinetic, alone and in combination with dif-
ferent rates of imidacloprid and abamectin.

MATERIALS AND METHODS

Field Trial during Aug 2006 Demonstrating Efficacy of
Silwet L-77 as an Insecticide

The 3-year-old block of citrus trees to be
sprayed was located at the Water ConservII Re-
search Site, in Orange County, near Winter Gar-
den, Florida and consisted of Minneola (cross LB
89) trees planted 3.8-m apart in the row with rows
6.1-m apart. The 20 experimental trees were ap-
proximately 1.2 to 1.5 m tall, and the treatments
were randomly chosen by coin toss. Trees initially
contained flush less than 4 cm long with eggs and
small psyllid nymphs. Ten trees were treated with
500 mL of Silwet L-77 surfactant (99.5% poly-
alkyleneoxide modified heptamethyltrisiloxane,
Helena Chemical Co., Collierville, TN) at a rate of
0.05% (v:v), or 500 ppm. Ten trees also were
treated with 500 mL of water each using a 12-gal
(45.5 L) battery-operated sprayer (Scorpion
sprayer, AgSouth, LLC, Union City, TN) cali-
brated to deliver 1.0 gpm (3.8 L per min) at 60 PSI
(27.2 kg/6.45 square cm).
A pre-treatment sample of 2 shoots was ran-
domly collected from each tree, and each shoot
was placed in a plastic bag. An hour after treat-
ment, a post-treatment sample of 2 shoots per
tree was collected from all trees, as described for
the pre-treatment samples. Plastic bags contain-


March 2008







Srinivasan et al.: Management D. citri Nymphs with Insecticides


ing shoots were stored in an ice chest with ice
packs for the trip to Gainesville. At Gainesville,
the number of dead or live psyllids nymphs per
shoot and the shoot length was recorded. Data
were analyzed by Proc ANOVA (version 9.1) (SAS
Institute 1996), and means were separated with
Fisher's least significant difference (LSD) at the
5% significance level.

Laboratory Studies with Silwet L-77 Using Eggs,
Nymphs, or Adults of D. citri

A series of laboratory trials were conducted fol-
lowing this initial field trial to evaluate the toxic-
ity of Silwet L-77 alone and in combination with
imidacloprid (Provado 1.6 Flowable, Bayer Crop-
Science, Research Triangle Park, NC) against
eggs, nymphs, and adults ofD. citri.
Silwet L-77at 0.05%, imidacloprid at one-tenth
the lowest label rate (LLR), imidacloprid at the
LLR (1 oz/10 gal of water or 0.8 mL/L of water)
and Silwet L-77at 0.05% with one-tenth the LLR
of imidacloprid were used to evaluate toxicity to
eggs ofD. citri. Potted citrus trees with at least 6
new flushes per tree were selected. The trees were
placed inside nylon fabric cages at the University
of Florida, Department of Entomology and Nema-
tology greenhouse, Gainesville at 18-36C, 35-
80% RH under a 16L:8D photoperiod. Ovipositing
females were released into the cage (approxi-
mately 5 females per tree) for a period of 72 h.
Branches of a single tree containing eggs were
hand dipped into treatment solutions for 10 s. Be-
cause the branches were hand dipped, each
branch was considered a replicate. Water-treated
trees served as controls. The trees were left undis-
turbed for a period of 5-7 d and the number of un-
hatched eggs and dead or live nymphs on each
shoot was counted and recorded under a dissect-
ing microscope. Percentage mortality data were
subjected to arcsine-square root transformation
when needed to mitigate the skewness of the data
and meet the requirements of normality. Analysis
of variance was estimated using Proc ANOVA
(SAS Institute 1996) to detect differences among
treatments, if any, and treatment means were
separated using Fisher's LSD.
The bioassay protocol for psyllid nymphs was
modified from Cowles et al. (2000). A preliminary
bioassay indicated that Silwet L-77 at 50 ppm
killed allD. citri nymphs, so Silwet L-77 at 0, 10, 20,
30, 40, and 50 ppm were used for this experiment.
Five shoots with approximately 20 nymphs per
shoot (approximately 100 nymphs per concentra-
tion) were used for each treatment. The shoots with
nymphs (primarily 1-3 instars) were completely
dipped in different treatment concentrations for 5
s. The shoots were then placed into petri dishes
lined with a filter paper to absorb excess moisture.
The experiment was conducted in a growth cham-
ber at 24C, 77% RH under a 16L:8D photoperiod.


The number of dead or live psyllid nymphs was
counted after 24 h. The death of nymphs was con-
firmed by touching each nymph with an insect pin.
Shoots treated with water alone served as a control.
Concentration-mortality analyses were conducted
using Proc Probit (SAS Institutel996).
Adults that were approximately 2 weeks old
were treated with Silwet L-77 at 0.05%, imidaclo-
prid at one-tenth the LLR, imidacloprid at the
LLR, and Silwet L-77 at 0.05% + one-tenth the
LLR of imidacloprid. Adults were chilled for sev-
eral minutes at 5C to inactivate them and 10-15
adults were placed on a filter paper-lined petri
plate. One mL of each treatment was topically ap-
plied with a 1-mL syringe directly to psyllid
adults placed on a filter paper and each treatment
had 4 replicates. Controls included water or insec-
ticide alone at the LLR. The treated psyllids were
moved to a 15-mL plastic vial and a single mature
citrus leaf was placed in the vial as a food source.
The vials were tightly secured using cheesecloth
to prevent escape. The experiment was conducted
in a growth chamber at 24C, 77% RH with a
16L:8D photoperiod. The number of dead or live
psyllids was counted after 24 h. Statistical analy-
ses were performed as for eggs.

Field Trial during Oct and Nov 2006

After the laboratory bioassays above indicated
that Silwet L-77 alone and in combination with
one-tenth the LLR of imidacloprid killed nymphs
and adults ofD. citri, a field trial was conducted to
confirm whether these treatments could suppress
psyllids in citrus groves. Five treatments were
evaluated: water; Silwet L-77 at 0.05%; imidaclo-
prid at one-tenth the LLR (or 1 oz/10 gal of water
or 0.8 mL/1 L of water); imidacloprid at the LLR;
and Silwet L-77 at 0.05% in combination with
one-tenth the LLR of imidacloprid. Each treat-
ment was replicated 10 times in a completely ran-
domized block design using a total of 50 trees. The
3-year-old block of Mineola trees (cross LB89) was
the same one used in the first field trial (described
above) at the Water ConservII Research Site in
Orange County. Trees initially contained a flush
of growth less than 4 cm long that contained eggs
and small psyllid nymphs. Individual trees were
identified with flagging. A pretreatment sample of
4 shoots was randomly collected from each tree,
and each shoot was placed in a separate plastic
bag. An hour after treatment, a post-spray sample
of 4 shoots per tree was collected from all trees, as
described for the pre-treatment samples. Plastic
bags containing shoots were stored in an ice chest
with ice packs for the trip to Gainesville. Trees
were sprayed as described above.
Four to 6 selected shoots in a node on each tree
were tagged with plastic tape prior to spraying.
These tagged shoots were used for subsequent
sampling, assuring that sampled shoots had been







Florida Entomologist 91(1)


treated and were not new growth subsequent to the
spray. A single shoot was sampled each week, and
when the nodes no longer had any shoots, shoots of
the expected size were selected from that tree. All
psyllid nymphs on each shoot were counted. Sam-
pling was conducted just before and just after
treatment and each week for 6 consecutive weeks.
The effect of the treatments on shoot length
and shoot growth was monitored to evaluate the
possibility of phytotoxicity. Shoots taken to the
laboratory to estimate the density of psyllid
nymphs were measured using a caliper and the
observations recorded. In order to monitor the ef-
fect of treatments on shoot growth, a single shoot
on each tree was tagged at the start of the exper-
iment and its growth was monitored over the en-
tire sampling period.
Residual toxicity of the treatments was as-
sessed by sampling mature foliage (dark green
leaves that were not on new shoots) each week for
5 weeks after treatment. One mature shoot was
collected from each treatment tree, and 2 leaves
from each shoot were placed into 2 separate 50-
mL vials. Two adults of both sexes from our labo-
ratory colony that were approximately 2 weeks
old were released into each vial and placed in a
growth chamber at 23C, and 70% RH under a
16L:8D photoperiod. Adult survival on the ma-
ture treated leaves was recorded after 48 h.
Percentage adult mortality data were sub-
jected to arcsine-square root transformation
when needed to mitigate the skewness of the data
and meet the requirements of normality. Treat-
ment differences with respect to nymphal counts,
shoot length, and adult survival were estimated
using Proc ANOVA (SAS Institute 1996). Treat-
ment means were separated using Fisher's LSD.

Concentration-Mortality Data for Silwet L-77
and Kinetic in Laboratory Bioassays

In order to compare the efficacy of Silwet L-77
with Kinetic (proprietary blend of polyalkyleneox-
ide modified polydimethylsiloxane and nonionic
surfactants (99%) and non-surfactant ingredients
(1%) (Helena Chemical Company), laboratory bio-
assays were conducted using the bioassay proto-
col modified from Cowles et al. (2000). A prelimi-
nary bioassay indicated that Silwet L-77 and Ki-
netic at 50 ppm killed all nymphs so Silwet L-77
and Kinetic at 0, 10, 20, 30, 40, and 50 ppm were
tested. One shoot with approximately 100
nymphs per shoot was used for each treatment.
The shoots with nymphs were dipped in different
treatment concentrations for 5 s. The shoots were
then placed into petri plates lined with filter pa-
per to absorb excess moisture. The experiment
was conducted in a growth chamber at 24C, 77%
RH, under a 16:8D photoperiod. The dead psyllid
nymphs were counted after 24 h. The death of
nymphs was confirmed by touching each nymph


with an insect pin. Probit analyses were con-
ducted as described above.

Greenhouse Bioassays Using Potted Citrus Trees
to Compare Silwet L-77 or Kinetic Alone and in
Combination with Abamectin or Imidacloprid to Eggs,
Nymphs, or Adults of D. citri

All experiments included the same 18 treat-
ments: untreated control, water control, Silwet L-
77 at 0.05%, Kinetic at 0.05%, imidacloprid at one-
fourth the LLR, imidacloprid at one-half the LLR,
imidacloprid at the LLR, abamectin (Agrimek
0.15EC, Syngenta Chemical Company) at one-
fourth the LLR, abamectin at one-half the LLR,
abamectin at the LLR, Silwet L-77+ one-fourth
the LLR of imidacloprid, Silwet L-77+ one-half the
LLR of imidacloprid, Silwet L-77 + one-fourth the
LLR of abamectin, Silwet L-77+ one-half the LLR
of abamectin, Kinetic + one-fourth the LLR of im-
idacloprid, Kinetic+ one-half the LLR of imidaclo-
prid, Kinetic + one-fourth the LLR of abamectin
and Kinetic + one-half the LLR of abamectin.
To assess toxicity of these treatments to eggs of
D. citri, pruned potted citrus trees with at least 6
new flushes per tree were selected. The trees were
placed inside cages in a greenhouse at the Univer-
sity of Florida, Department of Entomology and
Nematology, Gainesville at 18-36C, 35-80% RH
under a 16L:8D photoperiod. Ovipositing females
were released into the cage (5 females per tree) for
a period of 72 h. The adults were aspirated out after
72 h. The trees were sprayed using a different dis-
posable spray gun (Preval spray gun, Yonkers,
NY) for each treatment. The spray gun was held 90
cm from the trees and moved around the tree dur-
ing a 15-sec interval that produced fine droplets
covering ca. 90% of the foliage. The trees were left
undisturbed for a period of 5-7 d and the unhatched
eggs and dead or live nymphs on each shoot were
counted under a dissecting microscope and re-
corded. The entire experiment was conducted twice.
Percentage mortality data were subjected to arc-
sine-square root transformation when needed to
mitigate the skewness of the data and meet the re-
quirements of normality. Analysis of variance was
estimated using Proc ANOVA (SAS Institute 1996)
to detect differences among treatments and treat-
ment means were separated using Fisher's LSD.
Toxicity to nymphs was assessed using the same
methods as for the eggs, except that 5 ovipositing
females per tree were released into the cage for a
period of 72 h. After 3 to 4 d, when waxy excretions
from the first through third-instar nymphs were
observed, the trees were sprayed as described
above. The trees were left undisturbed for a period
of 3-5 d and the number of unhatched eggs and
dead or live nymphs on each shoot were counted
under a dissecting microscope and recorded. The
entire experiment was conducted twice. Statistical
analyses were performed as for eggs.


March 2008







Srinivasan et al.: Management D. citri Nymphs with Insecticides


Toxicity to adults was assessed by treating pot-
ted citrus trees after covering the exposed soil of
the pot with a thin plastic film and then a double
layer of paper coffee filters. The coffee filters were
taped to the pot to prevent adults from becoming
lost in the soil. The sprayed trees were pruned to
fit into a plexiglass cylinder 50 cm tall with a 10-
cm radius. Then, 20 adults that were approxi-
mately 2 weeks old were aspirated into a 50-mL
plastic vial and introduced into the cylinder. The
trees were placed in the greenhouse at the Uni-
versity of Florida, Department of Entomology and
Nematology, Gainesville at 18-36C, 35-80% RH
under a 16L:8D photoperiod. The number of dead
or live adults was estimated after 72 h. The entire
experiment was repeated 5 times. Statistical
analyses were performed as for eggs and nymphs.

Toxicity of Imidacloprid to Adult Psyllids
on Detached Leaves vs. Attached Leaves

In order to evaluate whether our use of de-
tached leaves from the field experiment was ap-
propriate for evaluating residual toxicity ofimida-
cloprid to adults of D. citri, 2 experiments were
conducted simultaneously. Eight citrus trees were
sprayed with imidacloprid at the LLR. Two of
these trees were pruned on 4 dates (immediately
after spray and 1, 2, and 4 weeks later) and cov-
ered with a plexiglass cylinder, as described above,
and left at the greenhouse at 18-36C, 35-80% RH
under a 16L:8D photoperiod. Twenty adult psyl-
lids were introduced into the cylinder and the
number of dead or live adults was counted after 2
d to assess mortality on attached leaves. Two
leaves were also removed from each tree and indi-
vidually placed into a 50-mL vial and 2 adults
were introduced into each vial as described for the
residual toxicity tests. The vials were placed in a
growth chamber at 23C, and 70% RH under a
16L:8D photoperiod. The number of dead or live
adults was estimated after 2 d. Water-treated
trees and foliage from the same trees served as


controls. Mortality in each set of experiments
across each time interval was compared with wa-
ter-treated trees using Proc GLM (SAS Institute
1996) and differences across the treatments were
evaluated using Fisher's LSD. The mortality
achieved at each date in the 2 bioassay methods
also was compared using the same procedure. Re-
gression analyses were done using Proc REG (SAS
Institute 1996) to compare the decline in adult
mortality over time using the 2 assay methods.

RESULTS

Field Trial during Aug 2006 Demonstrating
Efficacy of Silwet L-77 as an Insecticide

Pretreatment and immediate post-treatment
counts of psyllid nymphs indicated no differences
between water- and Silwet L-77-treated trees (Table
1). Counts on subsequent weeks revealed a lower
mean number of nymphs on Silwet L-77-treated
trees when compared to water-treated trees on
weeks 1, 3, and 4 (Table 1). However, no differences
were found between the 2 treatments on weeks 2
and 5. Very few nymphs were found during week 5,
perhaps due to maturation of the tender shoots.
Pretreatment observations indicated no differ-
ences in shoot length between the treatments (Ta-
ble 2). Immediate post-treatment observations in-
dicated that shoots on water-treated trees were
longer, perhaps due to an artifact of sampling.
These differences, however, were not significant
during subsequent samples and indicate that the
Silwet L-77 application had no effect on shoot
length. No symptoms of phytotoxicity on this cul-
tivar were observed in the field.

Laboratory Studies with Silwet L-77 and Imidacloprid
Using Eggs, Nymphs, or Adults of D. citri

Silwet L-77 applied at the rate of 0.05% by it-
self killed all the nymphs tested using the shoot
dipping protocol and hence no combinations with


TABLE 1. EFFECT OF SILWET L-77 (0.05% V:V) ON THE NYMPHS OF THE ASIAN CITRUS PSYLLID AT THE WATER CON-
SERVII RESEARCH SITE IN FLORIDA DURING AUG 2006.

Mean SE number of psyllid nymphs/shoot

Sample interval Water Silwet L-77 P

Pretreatment 23.9 3.7 a 24.0 3.8 a 0.99
Immediate post treatment 9.6 2.0 a 8.3 2.4 a 0.67
Week 1 10.5 2.1 a 2.3 0.6 b 0.0001
Week 2 7.8 2.9 a 3.8 1.3 a 0.21
Week 3 3.1 0.8 a 1.2 0.4 b 0.03
Week 4 1.2 0.4 a 0.1 0.1 b 0.003
Week 5 0.1 0.02 a 0.2 0.03 a 0.45

*Treatment means were analyzed using Proc ANOVA and treatment differences were analyzed using Fisher's LSD. Treatments
with the same letter within a row are not significantly different from each other (P < 0.05).







Florida Entomologist 91(1)


March 2008


TABLE 2. EFFECT OF SILWET L-77 ON SHOOT LENGTH OF TREATED TREES AT THE WATER CONSERVII RESEARCH SITE
IN FLORIDA DURING AUG 2006.

Mean SE shoot length (cm)

Sample interval Water Silwet (0.05%) P

Pretreatment 9.1 0.5 a 10.1 0.8 a 0.16
Immediate post treatment 10.3 0.5 a 8.2 0.4 b 0.002
Week 1 10.1 0.5 a 10.5 0.4 a 0.54
Week 2 13.5 0.9 a 13.6 0.8 a 0.95
Week 3 15.6 0.6 a 14.7 0.6 a 0.25
Week 4 18.1 0.6 a 16.8 0.5 a 0.10
Week 5 19.2 0.7 a 18.8 0.6 a 0.63
Week 6 19.1 0.8 a 19.8 0.7 a 0.47

*Treatment means were analyzed using Proc ANOVA and treatment differences were analyzed using Fisher's LSD. Treatments
with the same letter within a row are not significantly different from each other (P < 0.05).


imidacloprid were tested (data not shown). At 50
ppm, Silwet L-77 killed more than 99% of the
psyllid nymphs. The lethal concentrations and
their fiducial limits are presented in ppm (Table
3). These rates are well below the 500 ppm
(0.05%) rate recommended for field use.
A preliminary study using Silwet L-77 at
0.05% indicated that it was not toxic to eggs, be-
cause most eggs hatched and developed into
healthy nymphs. As a result, a combination of Sil-
wet L-77 (0.05%) + imidacloprid was tested (Table
4). Mortality of eggs included the eggs that did not
hatch, as well as the first-instar nymphs that died
soon after hatching. Silwet L-77 by itself caused
the least mortality (0.3%) to eggs on shoots dipped
into the solution among all treatments. The high-
est mortality was recorded on shoots treated with
the LLR of imidacloprid (97.2%), while the com-
bined treatment of Silwet L-77 + one-tenth the
LLR of imidacloprid caused 71.6% mortality (Ta-
ble 4). Imidacloprid at one-tenth the LLR resulted
in only 50.4% mortality of eggs. Combining Silwet
L-77 with one-tenth the LLR of imidacloprid
clearly provided improved control of eggs com-
pared to Silwet L-77 alone. Though not statisti-
cally significant, the combination also provided
improved control of eggs compared to one-tenth
the LLR of imidacloprid (Table 4).


Silwet L-77 applied topically at the rate of
0.05% killed 47% of adults, while imidacloprid at
one-tenth the LLR killed 46.3% of adults (Table
4). A combination of Silwet L-77 and one-tenth
the LLR of imidacloprid increased mortality of
adults to 100%, which was equal to the LLR of im-
idacloprid (100%). All the water-treated adults
survived, as expected (Table 4). These laboratory
results suggest that control of eggs, nymphs, or
adults could be achieved with a combination of
one-tenth the LLR of imidacloprid plus Silwet L-
77 (0.05%).

Field Trial during Oct and Nov 2006

Pre-treatment observations indicated that
trees to be sprayed with imidacloprid at the LLR
had fewer nymphs than the rest of the treatments
(Table 5), but this could have been due to sampling
error. There were significantly more living nymphs
on the water-treated control trees immediately af-
ter treatment (Table 5), suggesting that Silwet L-
77 and imidacloprid alone and in combination with
Silwet L-77 killed mostD. citri nymphs.
Over the total post-spray period, there were
significantly more living psyllid nymphs/shoot on
the water-treated trees (mean = 17.4) than on the
trees treated with Silwet L-77 (1.8) or imidaclo-


TABLE 3. CONCENTRATION-MORTALITY RESPONSE OF ASIAN CITRUS PSYLLID NYMPHS TO SILWET L-77 UNDER LABO-
RATORY CONDITIONS.

Lethal concentration Concentration (ppm) Fiducial limits (ppm) Intercept Slope

LC50 7.3 6.5-8.1 2.9484 -2.5485
LC90 19.9 18.8-21.1
LC95 26.4 24.8-28.5
LC99 45.0 40.6-50.9

*Mortality at each Silwet L-77 concentration was subjected to probit analysis using Proc Probit. Five shoots with at least 20
nymphs per shoot were tested for each concentration.







Srinivasan et al.: Management D. citri Nymphs with Insecticides


TABLE 4. TOXICITY OF SILWET L-77 ALONE OR IN COMBINATION WITH IMIDACLOPRID TO PSYLLID EGGS USING A SHOOT-
DIP BIOASSAY AND TO ADULTS USING A TOPICAL APPLICATION METHOD AT 24 C, 77% RH UNDER A 16L:8D
PHOTOPERIOD.

Mean % mortality SE Mean % mortality SE
Treatment of eggs P < 0.0001 of adults P < 0.0001

Silwet L-77 at 0.05% 0.3 0.3 c 47.0 4.5 b
Imidacloprid at one-tenth the LLR 50.3 12.5 b 46.3 10.6 b
Imidacloprid at the LLR 97.2 1.3 a 100 a
Silwet + one-tenth the LLR of imidacloprid 71.6 12.9 b 100 a
Water -0 c

*Treatment means were analyzed using Proc ANOVA and treatment differences were analyzed using Fisher's LSD. Treatments
with the same letter within a column are not significantly different from each other (P < 0.05). Six shoots were sampled for each treat-
ment to estimate egg mortality, each shoot had 3-113 eggs, number of adults sampled for each treatment and water check = 45-53.


prid at one-tenth the LLR (1.6) (P < 0.0001) (Table
5). There were no significant differences among
the Silwet L-77 and imidacloprid treatments over
this total post-spray period, although there was a
trend for trees treated with imidacloprid at the
LLR and trees treated with Silwet L-77 + one-
tenth the LLR to have lower psyllid densities
(means = 0.3 and 0.9 per shoot, respectively, over
the experiment). These data suggest that Silwet
L-77 alone or in combination with one-tenth the
LLR of imidacloprid provided control of nymphs
equivalent to that of the LLR of imidacloprid.
When the data were analyzed by week there
were always differences between the water-
treated trees and the trees treated with Silwet
L-77 and/or imidacloprid (Table 5). There were
sometimes differences among the treatments,
particularly during weeks 2 and 4.
Measurements of shoot length, recorded to de-
termine whether Silwet L-77 or imidacloprid af-
fected shoot elongation, did not exhibit any clear
pattern among the treatments (data not shown).
When imidacloprid was applied at one-tenth the
LLR, shoots at the end of the experiment aver-
aged 10.4 cm (S.E. = 1.0), which was not differ-
ent from shoot lengths of trees treated with the
LLR of imidacloprid (9.6 + 0.9) (P = 0.27). Shoot
lengths in both imidacloprid treatments (one-
tenth the LLR and the LLR) were not different
from the trees treated with Silwet L-77. Shoot
length in the water-treated trees and the trees
with the combined treatment of Silwet L-77 and
imidacloprid were not different from each other.
Weekly observations on shoot length indicated
there were minor differences across treatments at
weeks 1 and 5. However, because differences did
not exhibit any clear pattern, we conclude that
there was no effect of treatments on shoot length
in this cultivar under these growing conditions.
During the course of the trial, visual observations
also indicated no phytotoxicity symptoms.
Shoot growth of tagged shoots, that were
known to have been treated, over the 6 weeks of
the experiment was not different across treat-


ments (Table 6). These results indicate that Sil-
wet L-77 and imidacloprid, either alone or in com-
bination, did not have any effect on shoot growth.
The shoot length decreased during the last 2
weeks of sampling, probably due to frost injuries
on shoot tips.
Residual toxicity of mature treated foliage to
adults persisted for only 2 weeks in the foliage
treated with the LLR of imidacloprid (Table 7).
During the entire post-treatment period, the mor-
tality of adults on treated citrus foliage was high-
est on leaves collected from trees sprayed with the
LLR of imidacloprid (mean = 24%), followed by
mortality on foliage sprayed with a combined
treatment of Silwet L-77 and one-tenth the LLR
of imidacloprid (11.3%), while 4.6% and 8.8% mor-
tality of adults was observed on the water- and
Silwet L-77-treated foliage, respectively (Table 7).
The mortality on foliage treated with one-tenth
the LLR of imidacloprid also averaged 4.6% over
the post-treatment period. The highest rate of
mortality (55%) occurred during the first week af-
ter treatment with the LLR of imidacloprid, indi-
cating that adults are difficult to control. The in-
crease in mortality of adults during the sixth
week after treatment among all the treatments
compared to weeks 3, 4, and 5, was due to un-
known reasons, and was unlikely due to the effect
of imidacloprid because mortality also increased
in the 2 controls (water and Silwet L-77 treat-
ments).

Concentration-Mortality Data for Silwet L-77
and Kinetic in Laboratory Bioassays

Mortality of psyllid nymphs caused by Silwet
L-77 or Kinetic was not different from each other
at the tested concentrations using a shoot-dip bio-
assay. At 50 ppm, both Silwet L-77 and Kinetic
killed >95% of the psyllid nymphs. The lethal con-
centrations and their fiducial limits are presented
in ppm (Table 8). These data reveal that both Sil-
wet L-77 and Kinetic are equally effective in kill-
ing psyllid nymphs using the shoot dip assay in








(C




TABLE 5. EFFECT OF SILWET L-77 ALONE OR IN COMBINATION WITH IMIDACLOPRID AT THE LOWEST LABEL RATE (LLR) ON SURVIVAL OF PSYLLID NYMPHS AT THE WATER
CONSERVII RESEARCH SITE IN FLORIDA BETWEEN 5 OCT AND 15 NOV 2006.

Mean SE living nymphs / shoot

Pre spray Immediate post spray Week 1 Week 2 Week 3 Week 4 Week 5 Total post-spray period
Treatment P< 0.0001 P <0.0001 P< 0.0001 P< 0.0001 P< 0.0001 P = 0.05 P = 0.30 P < 0.0001

Water 33.9 3.9 a 32.1 3.9 a 29.3 5.5 a 8.5 2.0 a 10.3 3.7 a 5.8 3.2 1.8 1.5 a 17.4 5.3 a
Silwet L-77 (0.05%) 35.0 3.0 a 1.2 0.3 b 4.6 1.0 b 3.5 1.3 b 0.9 0.4 b 0.1 0.1 b 0.5 0.4 a 1.8 0.7 b
Imidacloprid at one-tenth
the LLR 31.0 + 2.9 a 2.1 + 0.7 b 2.9 + 0.8 b 1.0 0.4c 0.4 0.3 b 3.1 1.9 ab 0 a 1.6 + 0.5 b
Imidacloprid at the LLR 23.1+ 1.8 b 0.1 0.1b 1.0 + 0.5 b 0.6 + 0.3 c 0.2 + 0.2 b 0.2+ 0.1 b Oa 0.3 + 0.2 b
Silwet L-77 (0.05%) + one-
Set t id oprd 35.1 + 3.5 a 0.9 0.5 b 1.6 0.5 b 1.0 0.4 c 0.3 0.3 b 2.1 1.0 ab 0.1 + 0.6 a 0.9 0.3 b
tenth the LLR of imidacloprid
*Treatment means were analyzed using Proc ANOVA and means were separated using Fishers' LSD with P = 0.05; treatments with the same letter within a column are not significantly
different from each other.


TABLE 6. EFFECT OF SILWET L-77 ALONE OR IN COMBINATION WITH IMIDACLOPRID AT THE LOWEST LABEL RATE (LLR) ON GROWTH OF SINGLE TAGGED SHOOTS (N = 10) AT
THE WATER CONSERVII RESEARCH SITE BETWEEN 5 OCT AND 15 NOV 2006.

Mean shoot length (cm S.E.)

Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Entire post-spray period
Treatment P = 0.96 P = 0.44 P = 0.21 P = 0.85 P = 0.83 P = 0.53 P = 0.25

Water 5.9 0.7 9.6 1.3 12.5 1.2 14.0 1.7 14.0 1.7 12.6 1.3 11.4 1.4
Silwet L-77 (0.05%) 6.3 0.6 8.9 1.1 11.3 1.5 12.5 1.7 13.8 1.5 11.9 1.7 10.8 1.2
Imidacloprid at one-tenth the LLR 6.4 0.6 7.9 0.7 9.3 0.8 14.6 + 2.7 12.5 + 1.9 12.5 + 2.3 10.5 1.4
Imidacloprid at the LLR 6.2 0.6 10.1 0.8 13.0 1.3 14.4 1.5 14.3 1.8 14.6 2.0 12.1 1.5
Silwet L-77 (0.05%) at one-tenth the
LLR ofimidacloprid 6.1 + 0.4 9.4 0.8 11.3 1.7 12.6 1.3 12.4 1.0 11.0 1.4 10.5 1.1

*Treatments means were analyzed using Proc ANOVA and means were separated using Fishers' LSD with P = 0.05.


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Srinivasan et al.: Management D. citri Nymphs with Insecticides


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the laboratory at concentrations far below the 500
ppm used in the field.

Greenhouse Bioassays Using Potted Citrus Trees
to Compare Silwet L-77 or Kinetic Alone and in
Combination with Abamectin or Imidacloprid to Eggs,
Nymphs, or Adults of D. citri

Silwet L-77 and Kinetic killed very fewD. citri
eggs when the potted citrus trees were sprayed
(Table 9). The percentage of egg mortality on Sil-
wet L-77- or Kinetic-treated trees (2.5%) was not
different from the egg mortality observed on the
water-treated (0.3%) or untreated (1.4%) trees
(Table 9).
Egg mortality on the imidacloprid-treated
trees tested at one-fourth, one-half, and at the
LLR was not different (Table 9). The D. citri eggs
experienced 99-100% mortality at all 3 rates of
imidacloprid. When Silwet L-77 or Kinetic were
combined with one-fourth or one-half the LLR of
imidacloprid, egg mortality ranged from 95.2% to
100%, which was not different from mortality
caused by imidacloprid alone at these rates. Thus,
Silwet L-77 did not improve mortality caused by
imidacloprid to D. citri eggs (Table 9).
Abamectin at one-fourth the LLR caused lower
egg mortality (61.4%) than at one-half the LLR
(96.5%) or at the LLR (92.9%) (Table 9). When Sil-
wet L-77 was combined with abamectin at one-
fourth and one-half the LLR, mortality increased
to 98.8% and 97.8%, respectively, indicating that
Silwet L-77 improved the toxicity of abamectin to
D. citri eggs (Table 9). When Kinetic was com-
bined with abamectin at one-fourth the LLR, mor-
tality increased significantly from 61.4% to
86.3%. However, adding Kinetic did not improve
the efficacy of one-half the LLR of abamectin,
which was 83.5% with Kinetic and 96.5% without
Kinetic (Table 9). These data suggest that Silwet
L-77 is better at increasing the toxicity of abam-
ectin to D. citri eggs than Kinetic.
Mortality of nymphs on untreated and water-
treated trees averaged 0.4% and 1.7%, respec-
tively, while 73.3% of nymphs on Silwet L-77-
treated trees died (Table 9). Only 29.2% of the
nymphs died on trees treated with Kinetic, sug-
gesting that Silwet L-77 is more effective in sup-
pressing D. citri nymphs (Table 9). Mortality of
nymphs on trees sprayed with imidacloprid at
one-fourth, one-half, and at the LLR ranged from
94.8 to 99.5% (Table 9). There was a slight in-
crease in nymphal mortality when one-fourth and
one-half the LLR of imidacloprid was applied in
combination with Silwet L-77 (mortality was 99.4
and 99.7%, respectively), but the differences were
not significant.
Kinetic applied with one-fourth or one-half the
LLR of imidacloprid caused 92% and 100% mor-
tality of nymphs, respectively, which was not sig-
nificantly different from these rates of imidaclo-







Florida Entomologist 91(1)


TABLE 8. CONCENTRATION-MORTALITY RESPONSE OF ASIAN CITRUS PSYLLID NYMPHS TO SILWET L-77 IN COMPARISON
WITH KINETIC UNDER LABORATORY CONDITIONS.

Lethal concentration of Silwet L-77 Concentration (ppm) Fiducial limits (ppm) Intercept Slope

LC50 14.8 14.0-15.2 3.7546 -4.1267
LC90 28.0 26.8-29.3
LC95 33.7 32.0-35.8
LC99 52.3 47.8-57.9
Lethal concentration of Kinetic
LC50 12.6 11.8-13.3 4.5443 -5.2963
LC90 27.6 26.2-29.2
LC95 34.5 32.3-37.0
LC99 47.5 44.6-51.3

*Mortality at each Silwet L-77 and Kinetic concentration was subjected to probit analyses using Proc Probit. Five shoots with
at least 20 nymphs per shoot were tested for each concentration.


prid alone, so adding Kinetic or Silwet L-77 to im-
idacloprid did not significantly increase mortality
to nymphs (Table 9).
Abamectin at one-fourth the LLR killed fewer
nymphs (42.0%) than one-half the LLR (87.8%) or
the LLR (97.3%) (Table 9). However, when com-
bined with Silwet L-77, mortality at one-fourth the
LLR increased significantly from 42% to 96.8%
(Table 9). Combining Silwet L-77 with one-half the
LLR of abamectin resulted in 99% mortality com-
pared to 87.7% with abamectin alone, but these
were not significantly different. Nymphal mortal-
ity increased significantly from 42% to 85.6%
when one-fourth the LLR of abamectin was com-
bined with Kinetic. When one-half the LLR of
abamectin was combined with Kinetic, mortality
was 92.6% compared to 87.7% for abamectin
alone, but this was not significantly different
(Table 9).
Tests conducted by releasing adult psyllids
into a plexiglass cylinder enclosing pruned and
Silwet L-77- or Kinetic-sprayed trees resulted in
mortality rates of 4.3% and 1.7%, respectively,
which was not significantly different (Table 10).
No mortality occurred when adults were exposed
to water-treated or untreated trees. The mortality
rate of adults released into cylinders containing
trees sprayed with one-fourth the LLR of imida-
cloprid (49.9%) differed significantly from that of
adults exposed to one-half the LLR (76.7%), which
was in turn significantly lower than the mortality
caused by the LLR (100%). When Silwet L-77 was
combined with one-fourth the LLR of imidaclo-
prid, mortality of adults increased significantly
from 49.9% to 98.8%, which was not different
from the LLR ofimidacloprid. Likewise, mortality
increased significantly from 76% to 96.9% when
Silwet L-77 was combined with one-half the LLR
of imidacloprid (Table 10). Mortality of adults
exposed to foliage treated with one-half the LLR
of imidacloprid plus Silwet L-77 was not signifi-


cantly different from the mortality of adults
treated with the LLR ofimidacloprid (Table 10).
Mortality of adult D. citri exposed to foliage
from trees treated with abamectin at one-fourth
or one-half the LLR was 4.2% and 12.8%, respec-
tively (Table 10). However, abamectin applied at
the LLR killed 73.6% of the adults, which was sig-
nificantly lower than the mortality caused by the
LLR of imidacloprid (100%). Combining Silwet L-
77 with either one-fourth or one-half the LLR of
abamectin did not increase the toxicity of abamec-
tin to adults, with mortality rates of 15.2% and
1.8%, respectively, compared to 4.2 and 12.8%
mortality, respectively, for abamectin alone at
one-fourth and one-half the LLR.
The combination of Kinetic with abamectin at
one-fourth the LLR also did not increase toxicity.
At one-half the LLR of abamectin, adding Kinetic
resulted in 23.4% mortality compared to 12.8%
without Kinetic. These data indicate that abam-
ectin is not as effective in suppressing adults ofD.
citri as imidacloprid and that combining Kinetic
with abamectin did not result in increased mor-
tality of adults.

Greenhouse Bioassays Using Potted Citrus Trees
to Examine the Residual Toxicity of Imidacloprid
to Adult Psyllids Using Attached or Detached Leaves

As expected, mortality of adults on the water-
treated attached leaves was always lower than on
the imidacloprid-treated leaves, ranging from 0%
to 15% over the 4 weeks after treatment (Table
11). Mortality on the imidacloprid-treated at-
tached leaves immediately after treatment was
100%, and was 100% 1 week after treatment, but
declined to 71% during the second, to 47% during
the third, and was 58% during the fourth week af-
ter treatment. Regression analyses performed on
the data indicated a good correlation between de-
cline in mortality and time (R2 = 0.7834, slope =


March 2008







Srinivasan et al.: Management D. citri Nymphs with Insecticides


TABLE 9. TOXICITY OF SILWET L-77 AND KINETIC IN COMBINATION WITH IMIDACLOPRID OR ABAMECTIN TO EGGS OR
NYMPHS OF THE ASIAN CITRUS PSYLLID AT 18-36C, 35-80% RH UNDER A 16L:8D PHOTOPERIOD USING
SPRAYED POTTED TREES.


Treatment
Untreated
Water
Silwet L-77 (0.05%)
Kinetic (0.05%)
Imidacloprid at one-fourth the LLR
Imidacloprid at one-half the LLR
Imidacloprid at the LLR
Abamectin at one-fourth the LLR
Abamectin at one-half the LLR
Abamectin at the LLR
Silwet L-77 + imidacloprid at one-fourth the LLR
Silwet L-77 +imidacloprid at one-half the LLR
Silwet L-77 + abamectin at one-fourth the LLR
Silwet L-77 + abamectin at one-half the LLR
Kinetic + imidacloprid at one-fourth the LLR
Kinetic + imidacloprid at one-half the LLR
Kinetic + abamectin at one-fourth the LLR
Kinetic + abamectin at one-half the LLR


Mean % mortality
of eggs SE

P< 0.001
1.4 0.5 e
0.3 0.1 e
2.5 0.5 e
2.5 2.5 e
99.2 0.1 ab
100 a
99.8 + 0.2 a
61.4 17.2 d
96.5 3.5 ab
92. 9 4.0 bc
95.2 4.8 ab
100 a
98.8 0.5 ab
97.8 0.1 ab
99.5 0.1 a
99.1+ 0.8 ab
86.3 0.2 c
83.5 11.5 c


Mean % mortality
of nymphs SE

P < 0. 0001
0.4 0.2 g
1.7+ 0.1 g
73.3 4.6 e
29.2 4.9 f
97.0 + 3.0 abcd
99.5 0.3 ab
94.8 3.0 abcd
42.0 2.1 f
87.8 9.7 cde
97.3 2.2 abcd
99.4 + 0.4 abc
99.7 0.3 ab
96.8 +0.3 abcd
99.0 1.1 abc
92.0 + 7.4 bcde
100 a
85.6 10.8 de
92.6 + 7.4 abcd


*Treatments means were analyzed using Proc GLM and treatment differences were analyzed using Fisher's LSD. Treatments
with the same letter within a column are not significantly different from each other. LLR indicates the lowest label rate. Twelve
shoots in the treatments and untreated check were sampled for eggs and nymphs, each shoot had 10-425 eggs and 6-335 nymphs,
respectively.


-0.0573, intercept = 6.3111). The decline in mor-
tality could be attributed to a decline in the resid-
ual activity of imidacloprid.
Also as expected, mortality of adults on water-
treated detached leaves was zero except for week
2, when it was 25% (Table 11). Mortality of adults
immediately after the spray was 100% on the de-
tached leaves, and remained 100% for weeks 1
and 2, declining to 75% for week 3 and was 100%
for week 4. Regression analyses on the detached
leaves, however, indicated a weak correlation be-
tween decline in mortality and time (R2 = 0.0556,
slope = -0.0222, intercept = 4.1111), indicating
that imidacloprid remained toxic to the adult
psyllids using this detached leaf assay method.
The reasons) for the different results obtained
using these 2 assay methods is unclear, because
the detached leaves were from the same trees as
the attached leaves.
When these laboratory and greenhouse results
are compared to those obtained in the field trial
conducted at the Water ConservII Research Site
during Oct and Nov 2006 (Table 7), the laboratory
and greenhouse results indicate that imidacloprid
remains toxic to adults longer than when the
spray is applied in the field. In the field test, mor-
tality declined from 55% to 37% and then to 7.5%,
respectively, during the first 3 weeks post spray
(Table 7). By contrast, mortality of adults using


the detached leaves from the potted trees was
100%, 100%, 100%, 75%, and 100%, respectively,
over the 5 weeks of this laboratory assay (Table 9).

DISCUSSION

The potential use of Silwet L-77 as an insecti-
cide to suppress D. citri was initially discovered
when it was included as a control in a field trial to
evaluate an entomopathogenic fungus (Hoy et al.,
unpubl.). Silwet L-77 has been shown to increase
the efficacy of Bacillus thuringiensis as a control
agent of the citrus leafminer, Phyllocnistis citrella
Stainton, by increasing penetration into leaf
mines (Shapiro et al. 1998). Others have shown
that Silwet L-77 by itself causes direct toxicity to
insects. Imai et al. (1994) found that Silwet L-77
at 0.10% caused 100% mortality of green peach
aphid, Myzus persicae Sulzer. Silwet L-77 was
found to be toxic to at least 3 species oftephritids
(Purcell & Schroeder 1996). Silwet L-77 also is
toxic to mealybugs, thrips, spider mites, and
whiteflies (Chandler 1995; Skinner 1977; Smitley
& Davis 1997; Wood & Tedders 1997; Liu &
Stansly 2000; Cowles et al. 2000; Tipping et al.
2003). In our laboratory studies, although the
mechanisms are unclear, Silwet L-77 seems to ex-
hibit direct toxicity primarily to nymphs of D.
citri. Our laboratory, greenhouse, and field trials







Florida Entomologist 91(1)


March 2008


TABLE 10. RESIDUAL TOXICITY OF SILWET L-77 OR KINETIC ALONE OR IN COMBINATION WITH IMIDACLOPRID OR AB-
AMECTIN TO ADULTS OF THE ASIAN CITRUS PSYLLID AT 18-36 C, 35-80% RH UNDER A 16L:8D PHOTOPERIOD
USING SPRAYED POTTED TREES.


Mean % mortality SE


Treatment
Untreated
Water
Silwet L-77 (0.05%)
Kinetic (0.05%)
Imidacloprid at one-fourth the LLR
Imidacloprid at one-half the LLR
Imidacloprid at the LLR
Abamectin at one-fourth the LLR
Abamectin at one-half the LLR
Abamectin at the LLR
Silwet L-77 + imidacloprid at one-fourth the LLR
Silwet L-77 +imidacloprid at one-half the LLR
Silwet L-77 + abamectin at one-fourth the LLR
Silwet L-77 + abamectin at one-half the LLR
Kinetic + imidacloprid at one-fourth the LLR
Kinetic + imidacloprid at one-half the LLR
Kinetic + abamectin at one-fourth the LLR
Kinetic + abamectin at one-half the LLR


P< 0.001
Og
Og
4.3 3.0 egf
1.7 1.7 gf
49.9 8.9 c
76.7 7.8 b
100 a
4.2 2.7 egf
12.8 4.3 ed
73.6 12.2 b
98.8 1.2 a
96.9 2.0 a
15.2 6.8 def
1.8 1.8 gf
98.6 2.0 a
93.0 2.1 ab
8.5 2.0 def
23.4 6.7 d


*Treatments means were analyzed using Proc ANOVA and treatment differences were analyzed using Fisher's LSD. Treatments
with the same letter are not significantly different from each other. LLR indicates lowest label rate. Number of adults in treatments
and untreated check = 100.


indicate that Silwet L-77 can suppress psyllid
nymphs when applied at rates of 0.05% (Tables 1,
3, 5, 9). When Silwet L-77 is combined with lower-
than-label rates of imidacloprid or abamectin,
mortality of eggs is significantly increased (Tables
4, 9). Silwet L-77 in combination with one-fourth
or one-half the LLR of imidacloprid increased
mortality of D. citri adults significantly (Table
10). However, under field conditions, the LLR of
imidacloprid was significantly more effective in
controlling adults than one-tenth the LLR com-
bined with Silwet L-77 (Table 7). There were no
significant differences in densities of psyllid
nymphs in the field trial conducted during Oct-
Nov 2006 among the treatments (Silwet L-77
alone, one-tenth the LLR + Silwet L-77, and the
LLR of imidacloprid without Silwet) (Table 5).
These results suggest that Silwet L-77 could be-
come an important tool in managing Asian citrus
psyllid because it is inexpensive (estimated to
cost approximately $2.00/acre) and could reduce
the use of chemical pesticides, thus reducing pro-
duction costs for citrus growers. However, large-
scale field trials are needed to confirm this under
the diverse growing conditions and cultural prac-
tices employed in Florida.
Our data show that the methods used in the
laboratory bioassays affect our ability to predict
whether the laboratory rates tested of imidaclo-
prid (one-tenth, one-fourth, or one-half the LLR)
are likely to be as effective under grove conditions


in Florida. For example, when imidacloprid at
one-tenth the LLR was applied in combination
with Silwet L-77 to adults using a topical treat-
ment method in the laboratory, high rates (71%)
of mortality were observed (Table 4), but only
12.5% mortality was observed in the field trial
bioassay using treated foliage (Table 7), perhaps
principally due to UV-related photodegration
(Wamhoff & Schneider 1999). Lower insecticide
residual activity in the field was suspected to be
due to the use of detached leaves in the assay, but
the bioassays that compared detached and intact
leaves showed differences in residual toxicity of
imidacloprid to adults only during week 4 when
mortality on attached leaves was 57.9%, but was
100% on detached leaves (Table 11). Clearly, it is
difficult to predict the toxicity of a product pre-
cisely from laboratory bioassays due to differ-
ences in treatment and environmental conditions.
The laboratory data indicate that Kinetic is
less effective than Silwet L-77 in causing direct
mortality to nymphs (29% vs. 73% for Kinetic and
Silwet, respectively) (Table 9). When Kinetic was
combined with different rates of imidacloprid and
applied to eggs, it increased egg mortality equiva-
lent to that observed when eggs were treated with
Silwet L-77 and the same rates of imidacloprid
(Table 9). Kinetic and Silwet L-77 alone were
equivalent in causing low toxicity to adults (Table
10), but when each was combined with one-fourth
or one-half the LLR of imidacloprid equivalent







Srinivasan et al.: Management D. citri Nymphs with Insecticides


TABLE 11. RESIDUAL TOXICITY OF IMIDACLOPRID AT THE LOWEST LABEL RATE TO PSYLLID ADULTS ON ATTACHED OR
DETACHED CITRUS FOLIAGE AT 18-36 C, 35-80% RH UNDER A 16L:8D PHOTOPERIOD AND AT 24 C, 77% RH
UNDER A 16L:8D PHOTOPERIOD.

% Mortality SE % Mortality SE
Sampling interval Treatment on attached leaves on detached leaves

Immediate post spray Water 15 5.0 aB 0 aA
Imidacloprid 100 bA 100 bA
Week 1 Water 0 aA 0 aA
Imidacloprid 100 bA 100 bA
Week 2 Water 7.6 2.9 aA 25 14.4 aA
Imidacloprid 71.2 6.5 aA 100 bA
Week 3 Water 2.5 2.5 aA 0 aA
Imidacloprid 47.4 bA 75.0 14.4 bA
Week 4 Water 5.0 5.0 aA 0 aA
Imidacloprid 57.9 5.3 bA 100 bB

*Treatments means were analyzed using Proc ANOVA and treatment differences were analyzed using Fisher's LSD for each
time interval. Treatments with the same letter within a row (upper case) or column (lower case) are not significantly different from
each other. Number of adults in treatments and water check for each time interval: attached leaves = 40, detached leaves = 8.


and high mortality occurred (93-98.8%) (Table
10). Kinetic, however, did not increase the effec-
tiveness of abamectin over that of abamectin
alone (Table 10). Dr. R. Buker (Helena Chemical
Company, personal communication) indicated
that Silwet L-77 is less stable than Kinetic in wa-
ter with a high pH and impurities. Because our
tests were conducted with clean water at a mod-
erate pH, field trials to compare Kinetic and Sil-
wet L-77 in different regions should be conducted
to resolve whether water quality affects efficacy of
these products. It should also be noted that Ki-
netic is a proprietary mixture of organosilicone
compounds and other surfactants. Hence Kinetic
has a lower concentration of organosilicone sur-
factants than Silwet L-77, and might therefore
have poorer wetting properties than Silwet L-77.
Greenhouse bioassays, involving sprayed trees
to which adults were introduced shortly after the
spray droplets had dried, suggest that one-fourth
and one-half the LLR of imidacloprid in combina-
tion with Silwet L-77 may be sufficient to sup-
press adults ofD. citri under grove conditions (Ta-
ble 10). These results need to be confirmed under
grove conditions in different geographic regions of
Florida.
Silwet L-77 at 0.05% has not been reported to
exhibit phytotoxicity or to affect the growth of
plants on which it was tested, and we observed no
phytotoxicity or negative effects on shoot growth
in Silwet L-77-treated trees when compared to
water-treated trees in either of the 2 field trials.
Additional field trials in citrus in Florida using
different citrus cultivars under different growing
conditions will confirm the lack of phytotoxicity of
Silwet and Kinetic.


Natural enemies (such as lady beetles, lace-
wings, spiders (Michaud 2004) and a specialist
parasitoid, Tamarixia radiata (Waterston) (Hy-
menoptera: Eulophidae), which was released in a
classical biological control program (Hoy et al.
1999; Hoy & Nguyen 2000; Skelley & Hoy 2004)
were considered sufficient to suppress D. citri in
Florida's citrus groves prior to the confirmation
that greening disease is widely distributed in
Florida. Because greening disease is such a seri-
ous threat to Florida's citrus industry, other con-
trol options need to be considered. One issue that
was not resolved in this study is the effect of Sil-
wet L-77 alone or in combination with lower-than-
label rates of imidacloprid or abamectin on these
important natural enemies. Multiple applications
of pesticides will likely disrupt the natural ene-
mies of psyllids, as well as of other pests, and
could lead to pest outbreaks.
Current study suggests that Silwet L-77 or Ki-
netic, by exhibiting direct toxicity, could effi-
ciently manage D. citri nymphs alone but not eggs
or adults. However, Silwet L-77 or Kinetic, in con-
junction with insecticides, appear to be effective
in managing all life stages of D. citri. Neither Sil-
wet L-77 nor Kinetic is currently registered as a
pesticide and can only be applied as a spray adju-
vant. The lower efficacy of Silwet or Kinetic
against eggs and adults of D. citri suggests that
Silwet L-77 or Kinetic may not be a potential can-
didate for registration as an insecticide by itself
and the better solution may be to apply the orga-
nosilicone adjuvants in conjunction with low
rates of insecticides. Such an approach would be
ecologically less harmful and delay the develop-
ment of resistance.











ACKNOWLEDGMENTS

We thank R. Wilcox for assistance in rearing potted
citrus trees, and Bayer CropScience for providing sam-
ples ofimidacloprid, Helena Chemical Company for pro-
viding samples of Silwet L-77, Kinetic, and abamectin.
We also thank Dr. R. Buker, Helena Chemical Company
for advice and Harry Anderson and Michael Simms for
assistance in applying the field sprays. A special thanks
is extended to Orange County, the City of Orlando and
the Mid Florida Foundation for providing grove space
for this project at the Water ConservII research site.
This research was supported in part by the Davies,
Fischer and Eckes Endowment in Biological Control to
M. A. Hoy.

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