Bionomics and control of the two-lined spittle-bug, Prosapia bicincta, on Florida pastures and notes on Prosapia plagiat...

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Title:
Bionomics and control of the two-lined spittle-bug, Prosapia bicincta, on Florida pastures and notes on Prosapia plagiata in Costa Rica, (Homoptera: Cercopidae)
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116 leaves : ill. ; 28 cm.
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English
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Fagan, Ernest Brad, 1943-
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Subjects / Keywords:
Cercopidae   ( lcsh )
Homoptera   ( lcsh )
Beneficial insects   ( lcsh )
Insect pests   ( lcsh )
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bibliography   ( marcgt )
theses   ( marcgt )
non-fiction   ( marcgt )

Notes

Thesis:
Thesis (Ph. D.)--University of Florida, 1969.
Bibliography:
Includes bibliographical references (leaves 108-113).
Statement of Responsibility:
by Ernest Brad Fagan.
General Note:
Typescript.
General Note:
Vita.

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University of Florida
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All applicable rights reserved by the source institution and holding location.
Resource Identifier:
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notis - ACJ3994
oclc - 37683297
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Full Text











Bionomics and Control of the Two-Lined Spittlebug,

Prosapia bicincta, on Florida Pastures and Notes on

Prosapia plagiata in Costa Rica, (Homoptera: Cercopidae)












By
ERNEST BRAD FAGAN













A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL OF
THE UNIVERSITY OF FLORIDA
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE
DEGREE OF DOCTOR OF PHILOSOPHY











UNIVERSITY OF FLORIDA
1969















ACKNCdLEDGKENTS


The writer wishes to express his appreciation to the members of his

committee: Dr. L. C. Kuitert, Chairman; Dr. E. G. Kelsheimer; Dr. J. E.

McCaleb; and Dr. G. B. Killinger. A special debt of gratitude is extended

to Dr. L. C. Kuitert for his guidance, encouragement, and invaluable

assistance throughout this study. Sincere appreciation is extended to

Dr. W. G. Eden, Chairman, Department of Entomology, for his confidence,

counsel, and aid on many occasions. A special expression of gratitude is

extended to W. G. Genung, Everglades Experiment Station, and Dr. J. E.

McCaleb, Range Cattle Experiment Station, for advice, interest, and pro-

vision of working space at their stations. Thanks are bestowed to Dr.

Hugh Popenoe, Director of the Center for Tropical Agriculture, for finan-

cial assistance.

The writer gratefully acknowledges the assistance of the following:

Dr. D. H. Habeck for the 1967 light trap samples and special assistance

on several occasions; Dr. F. W. Mead for help with the literature and tax-

onomic problems; Dr. S. C. Schank for supplying some grass varieties; Dr.

H. A. Denmark for identification of the mites; Dr. L. R. Batra for identi-

fication of the fungus; Miss M. M. Sharpe for analysis of grass samples in

Florida; Dr. Hernan Fonseca for analysis of grass samples in Costa Rica;

and Dr. L. A. Hetrick for the 1966 light trap samples.

Special appreciation goes to Evaristo Morales M. and Ovidio Vargas

P. for their assistance and hospitality in Costa Rica.









Last and most, the writer's deepest gratitude goes to his wife,

Jimmye Dean, for her patience and constant encouragement throughout this

investigation and assistance in preparing this manuscript.
















TABLE OF CONTENTS



Page

ACKNOWLEDGMENTS .......... . .. ii

LIST OF TABLES. . . .. vi

LIST OF FIGURES . .. .. ... . viii

INTRODUCTION .. ....................... ...... 1

REVIEW OF THE LITERATURE. . . ....... .

ATERIALS AND METHODS ................. ...... .18
Rearing . . . .. 18
Light Trapping . . . 18
Height of traps . .... ..... 20
Traps using different colored lamps . .. 20
Periods of flight activity . ... 20
Sticky Board Traps . . 20
Grass Varieties Trial. . . ... .. 21
Chemical Control . . .. 21
1967 Experiments . . .. 2
1968 Experiments. . . ... .. 26

RESULTS AND DISCUSSION. . ... 28
Biology and Ecology . . .. .. 28
Eggs . .. . 28
Description . . .. 28
Hatching . . 28
Location. . . .. 28
Overwintering and the effects of moisture ... 30
Nymphs . . . 31
Description. . ... .... .. .32
Duration of nymphal stages . 32
Host plants. . . .... 33
Adults. .... ..... .. .. 33
Description. .. ...... .. .... .. 39
Feeding and mating habits . .. ... 39
Fecundity and longevity . 0
Predators and Parasites . .... 40
Life Cycle . . . 3
Light Trapping. . . .
Seasonal distribution . .. W.









Page


Effectiveness of traps at various heights.
Effectiveness of traps using different
colored lamps . .
Periods of flight activity . .
Effects of weather conditions on light trap
catches . .
Effectiveness of Colored Sticky Board Traps .
Description of Spittlebug Injury to Pangolagrass.
Effects of Damage on Nutritive Value of Grasses .


Economic Importance of Pro


Control . .


Light Traps .
Cultural Control .
Burning. .
Mowing .
Grazing .
Harvesting .
Renovation .. ....
Chopping and discing
Planting time. .
Grass-legume mixtures.
Grass varieties. .
Chemical Control .
1967 Experiments .
1968 Experiments .
Summary on chemical coi


Qa Uc IncUa. .
















ntrol. ........


ECONOMIC IMPORTANCE, CULTURAL AND CHEMICAL CONTROL OF
Prosapia plagiata ON KIKUYUGRASS IN COSTA RICA .
Synonymy . . .
Description. . . .
Influence of Feeding on Kikuyugrass .
Materials and Methods .
Results . . .
Discussion . .
Economic Importance . .
Control . .. ..
Cultural Control .......
Chemical Control . .
Materials and methods ..
Discussion and conclusions .


SUMMARY . . .

LITERATURE CITED . .

ADDITIONAL REFERENCES . .


108


BIOGRAPHICAL SKETCH .


. . . 116


y i bi T/i /t4


J'd
s















LIST OF TABLES


Table Page

1 Head capsule and mesothoracic wing pad measurements
(in mm) of the nymphal instars of Prosapia bicincta
in Florida . . .. 36

2 Host list of P. bicincta nymphs in Florida. .. 37

3 Effectiveness of blacklight traps placed with their
lamps centered at various heights above the ground
for attracting P. bicincta . ... h9

4 Effectiveness of colored fluorescent lamps in
attracting P. bicincta to light traps .... 51

$ Percentages of P. bicincta trapped per hour in nine
nights . . . 52

6 Effectiveness of different colored sticky board traps
for attracting male and female P. bicincta. .. 57

7 Effects of damage by adult P. bicincta on the
nutritive value of pangolagrass and bermudagrass .. 58

8 Visual rating of damage to grasses by P. bicincta in a
field trial . . 66

9 Chemical control of the first generation nymphs.
Experiment 1, 1967 . . .. 67

10 Effects of mowing and insecticide treatments on nymphs.
Experiment 2, 1967 . . 68

11 Control of adults with azinphosmethyl. Experiment 3,
1967 . .. . . 70

12 Control of nymphs with experimental insecticides.
Experiment h, 1967 . . .. 71

13 Control of adults with experimental insecticides.
Experiment h, 1967 . . .. 72

14 Control of adults with phorate. Experiment 1, 1968 73

vi








Table


15 Control of nymphs with phorate. Experiment 1, 1968. 7h

16 Control of P. bicincta with materials cleared for
use on pastures and vegetables. Experiment 2, 1968. 76

17 Control of adults with experimental insecticides on
St. Augustinegrass. Experiment 3, 1968 ... 79

18 Control of nymphs with experimental insecticides in
Belle Glade. Experiment 3, 1968 . .. 80

19 Control of nymphs with experimental insecticides on
pangolagrass, Experiment h, 1968 . ... 82

20 Effectiveness of experimental insecticides for pro-
tecting grasses from damage by P. bicincta 83

21 Control of nymphs with experimental systemic
insecticides. Experiment 5, 1968. . 86

22 Effectiveness of experimental systemic insecticides in
protecting grasses from damage by P. bicincta. ... 87

23 Effects of P. plagiata feeding on nutritive value of
kikuyugrass . . 96

2h Chemical control of P. plagiata nymphs. Costa Rica,
1967 . . . 101


Page














LIST OF FIGURES


Figure Page

1 Female two-lined spittlebugs caged on grass inserted
their eggs into moist filter paper wrapped around
the grass. . . 19

2 Light trap, which divided the catch into hourly
samples, used to determine periods of two-lined
spittlebug activity. . . 22

3 Gasoline powered knapsack blower used to apply
materials in the chemical control experiments. .... 23

h Development of Prosapia bicincta eggs. ... 29

5 The nymphal instars of P. bicincta . 3

6 Variations in the color markings of P. bicincta
adults . .. ... .. ..

7 Weekly occurrence of P. bicincta in light trap
catches for three years at Gainesville, Florida. .. 5

8 Average weekly occurrence of P. bicincta in blacklight
traps at the Range Cattle Experiment Station, Ona,
Florida, 1967 . ... .... h

9 Average weekly occurrence of male and female P.
bicincta in light trap catches at Gainesville,
Florida, 1967 . . .. 8

10 Percentages of male and female P. bicincta trapped
per hour in five nights . ...... 53

11 Effect of the minimum temperature on nightly light
trap catches of P. bicincta in September ....... 5.

3.2 Male and female P. plagiata. . 9

13 Areas of Costa Rica infested by P. plagiata in 1967. .. 100


viii
















INTRODUCTION


About thirty years ago Herbert Osborn (h8) stated in his classical

work on "Pasture and Forage Insects" that: "The immense place of grass

and other forage crops in our system of agriculture is possibly hardly

realized because of the more tangible results and available figures appear

in other products."

To a great extent, this statement is still true today. Taken in the

broadest sense, the grass family from which come rice, wheat, corn, sugar-

cane, and many other crops is the most important group of plants in agri-

culture. But the grass and forage that Professor Osborn was referring to

is that on which the livestock industry is based.

In Florida alone the dairy and beef industries are worth $87,200,000

and $69,000,000 per year,respectively (89). When the figures for the

sheep, horse, and swine industries, which are also more or less based on

grass, are added, the importance of pastures and forages becomes addition-

ally significant. Therefore any circumstances adversely affecting the pro-

duction of grass results in economic loss to the grower.

Many insects are associated with pasture grasses and a few are recog-

nized as economic pests. During outbreak years the two-lined spittlebug,

Prosapia bicincta (Say), is an economic pest and is capable of top killing

entire pastures through the injection of phytotoxic salivary substances

while feeding. The two-lined spittlebug is a native of Florida but has

only been reported as a pest since 195h. Why has this insect become eco-


1 -






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nomically important only in the last 15 years?

The answer undoubtedly lies in the fact that prior to 1935 less than

1,000,000 acres in Florida were il improved grass pastures. Then in 19h3,

three new grasses, Pensacola bahiagrass, pangolagrass, and Coastal bermuda-

grass were released. Since then more and more land has been developed as

improved pastures which are characterized by the use of intensive agronomic

practices and regular fertilization. By 1960, Florida had over 8,000,000

acres or about I of all usable land in pastures with 2,610,536 acres in

improved pastures. Approximately 750,000 additional acres are predicted

by 1975 (89).

Unfortunately, supplanting the native range with lush, nutritious

grasses is extremely favorable for pasture-infesting insects. Pasture

improvement tends to produce a stable monocultural environment which is

optimum for insects associated with grass. Consequently the two-lined

spittlebug, which had been innocuously associated with grass for years,

suddenly exhibited an unsuspected potential as an economic pest of im-

proved pasture grasses. This problem is certainly not confined to Florida.

In recent years, damage to improved pastures had been reported throughout

the southeast United States. Concurrently closely related species have

been reported damaging improved pastures throughout the Caribbean and Cen-

tral and South America. Because of the relatively recent existence of

the problem little information is available on the biology and control of

this insect. This is especially true for conditions in Florida.

In 1966, the Department of Entomology of the University of Florida

initiated a research project entitled the "Bionomics and Control of the

Two-lined Spittlebug, Prosapia bicincta (Say), in Tropical and Sub-tropical

America." This project was financed through a research grant from the






-3-


Center for Tropical Agriculture. It was originally planned that research

would be conducted in sub-tropical areas of Florida and in a tropical

country such as Costa Rica. It was hoped that information gained in sub-

tropical Florida would complement that from the tropics and vice-versa.

Research was conducted from September, 1966,to June, 1969,in three

locations in Florida. In addition, six weeks were spent in 1967 studying

a similar pest species of spittlebug, Prosapia plagiata (Distant), which

attacks pasture grasses at high elevations in Costa Rica. Accordingly,

this dissertation is divided into two sections. Greater emphasis is

placed on P. bicincta, with only a few notes given on the biology and

control of P. plagiata.















REVIEW OF THE LITERATURE


Because the subject deals with broad categories of only one species,

Prosapia bicincta, an exhaustive review of the literature was compiled.

With possibly a few exceptions, all references on biology and control were

incorporated into this review.

Systematics

Taxonomic Position from Metcalf (h4).

Order Homoptera
Suborder Auchenorrhyncha
Superfamily Cicadoidea
Family Cercopidae
Subfamily Cercopinae
Tribe Cercopini
Subtribe Monecphorina
Genus Prosapia
species bicincta (Say)

Synonymy

Cercopis bicincta Say, 1830. (51) (Type locality-Indiana)
MonecphorTa negecta Walker, 1851. (90)
Monecphora bicincta Signoret, 1853. (52)
Tomaspis fasciaticollis Stal, 186h. (54)
'Timasp's bicincta Stal, 186h. (5h)
Tomaspis neUTgT'ETa Berg, 1879. (4)
Prosapia bicincta Fennah, 1953. (17)

Description of the Adult

The adult is 8-10 mm in length. When viewed from above, the anterior

margin of the pronotum is straight and the head is narrower than the pro-

notum. The dorsal surface is black with the margin and median line of the

vertex, eyes, ocelli, and lateral margins of the pronotum red. Generally

two lines transverse the wing covers. These lines and an interhumeral









line are red to creamy-yellow (22). Many authors have described or pic-

tured the adult or have illustrated morphological structures such as the

genitalia or wing venation (1, 12, 13, 15, 17, 22, 30, hS, 53, 55, 16).

Relationship of the Species

P. bicincta is the sole representative of the genus north of Mexico.

Fennah (17) recognized four species as belonging to the genus. Concur-

rently, he placed six subspecies under bicincta. These are P. bicincta

bicincta (Say), P. b. ignipecta (Fitch), P. b. angusta (Walker), P. b.

basalis (Walker), P. b. bifascia (Walker), and P. b. fraterna (Uhler).

There is some doubt as to the validity of some of these subspecies, es-

pecially ignipecta and fraterna.

Races

Fitch (20) described Monecphora ignipecta as like M. bicincta but

without any bands or spots dorsally. Most authors have treated it as a

variety or color form (1, 15, h6, 55). However, Fennah (17) calls it a

geographical subspecies. In general, the dark form is more common in the

New England states but certainly is not confined to that area (h4). Boring

(5) concluded through a cytological study of the chromosomes that the dark

form was identical to the banded form.

Range

Metcalf (hh) lists the known geographical distribution of P. bicincta

as the United States: Arkansas, Connecticut, District of Columbia, Florida,

Georgia, Indiana, Iowa, Kansas, Louisiana, Massachusetts, Maryland, Maine,

Missouri, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Texas,

Virginia, West Virginia, Wisconsin; Jamaica, Mexico, Cuba, Central America,

Costa Rica, Guatemala, and the West Indies. The range can be generally

described as along the Atlantic slope from :J. York and Massachusetts
south, throughout the Gulf States and up the Mississippi valley as far as


- 5 -






- 6 -


central Iowa (1). Other states in which P. bicincta has been recorded are

Alabama (70), South Carolina (60), Delaware (67), and Michigan (30).

The two-lined spittlebug is a potential pest of improved pastures

throughout Florida. It has been reported as a pest on pastures north to

North Carolina (80) and west to Texas (87). The adults have been reported

injuring holly trees north to Delaware (66) and west to Kansas (73).

Host Plants

The nymphs have been recorded feeding on a wide variety of plants,

predominantly grasses. Only plants on which nymphs have been recorded

are considered here as the true hosts. Plants on which adults have been

recorded feeding are treated separately. Citation of a plant species by

several authors probably indicates that it is a favored host. A review of

host plants recorded in Florida is presented in the Results.

Host plants on which nymphs have been recorded

Scientific Name Common Name and Reference

Avena sativa L. oats 9
Andropogon muricatus grass 11
A. scoparius grass 30
Cynodon dactylon (L.) Pers. grass, bermuda 3, 7, h9, 63, 7b,
75, 77, 78, 79, 82, 85
Digitaria decumbens Stent grass, pangola 31, 62, 6h, 86,.
88
Digitaria sp. grass 30
Eremochloa ophiuroides (Munro) Hack. grass, centipede 7, 9, 42, 76
Panicumhumidianum grass 11
P. maximum Jacq. grass, guinea 11
Paspalum notatum Flugge grass, bahia 7
P:nnisrtumr glaucum (L,) R.Br, millet 65
P. 3 typhoides (Bur.) Stapf & Hubb. millet, pearl 9
7acinarM officinarum L. sugarcane 11, 33, 35
Sorghum halapense sorghum 11
S. vulgare Pers. sorghum, grain 69
Stenotaphrum secundatum (Walt.) Kuntze grass, St. Augustine a2, 62, 78,
8-, 85, 86
Zea mays L. corn 83






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Plants on which feeding adults have been worded

Scientific Name Comrron o ,- : Reeence

Andropogon scoparius grass h?
Cercis canadensis L. redbud trc. 2, 30, 68, 81
Ilex cornuta Burfordii DeFrance Burford ho- h9
I. opaca L. American h9, 71, 72
Malpighia glabra L. Barbados : y h2, 59

Pass and Reed (h9) listed 35 host plants for Si. Ciarolina but did

not differentiate the plants on which nymphs were r ied.

Description of the Egg

Beck (3), Byers (7), and Pass and Reed (h9) gi scriptions of the

egg and development. Although these accounts vary ..1iy, each report

follows a consistent pattern. Eggs range from 1.0, 1.09 im in length

and 0.27 mm to 0.37 mm in diameter. When first la" 2 egg is yellow,

elongate ovoid, tapered to a point at the anterior and bluntly rounded

at the posterior end. In h to 6 days an "egg burs' rms, splits the

chorion, and protrudes until the nymph emerges. A;. 0 to 12 iays, red

eye spots appear on either side of the egg near t'. :ior enr and two

red areas appear near the posterior end of the egj ? :% abdom'al region

of the embryo. These red areas later coincide wi7. 1 reddisi spots on

each side of the abdomen of the nymph. Under opti:. ;Aditioni. nymphs

emerge in 12-17 days and in the process of hatch. .12 the "c g burster"

and the attached cuticle. The eggs are pictured h, s (7).

Description of the Nymphal Stages

Some confusion exists concerning the number c-' Nyp.al instrs. Cardin

(11), Byers (7), and Washbon (91) report four i.. Ie Fas: nd Reed

(h9) report five. Weaver and King (92) found fi;v :-s for --e meadow

spittlebug and Fewkes (18) noted five for the suc2.: fro'ochoppD.r. The


literature indicates that five instars are the rutc


cercopids and. is






-8-


probably correct for P. bicincta. Metcalf (h3) illustrated the wing vena-

tion of the developing nymph and the antenna is illustrated by Moore (h6)

and Hanna and Moore (30).

Life History

Egg Stage

In Cuba, eggs required 12 to 20 days to hatch during the rainy sea-

son (11). Beck (3) reported that eggs placed on moist filter paper and

held at 800 F in the laboratory hatched in lh to 23 days with an average

of 17 days. Eggs held under more varying conditions hatched in 18 to 29

days. Pass and Reed (49) found that in the greenhouse the incubation

period averaged 12 days. In an experiment conducted by Byers (7) at 100%

R.H. and 800 F, eggs hatched in 17-39 days.

Nymphal Stages

No specific figures are available concerning the time required for

individual instars. However, Byers (7) indicates that about 7-10 days

are needed to complete an instar. Under insectary conditions, nymphs

required h3 to 75 days, or an average of 60 days to complete development

to the adult stage (3). Pass and Reed (49) reported that in the field,

the nymphal period ranged from 3h to 60 days. Nymphs required from 32

to 40 days to complete development in Cuba (11).

Adult Stage

In laboratory cages at 800 F and 70% R.H., males lived an average of

22.7 days and females an average of 23.7 days (7). Beck (3) kept field

collected adults alive as long as 30 days in the laboratory. In green-

house cages, where the temperature ranged from 220 to 350 C, field collected

adults remained alive for as long as six weeks (50). One male used in

experiments by Byers and Taliaferro (8) lived 33 days.






-9-


Life Cycle and Generations

When soil plugs containing overwintering eggs were brought into the

greenhouse, adults emerged in 81-105 days. In a similar experiment the

following year, adults emerged in 77-93 days. Light trap collection

curves and nymphal sampling curves indicate that it takes about 60 days to

complete a generation and there are two generations per year in Georgia (7).

Seasonal History

Adults have been taken early in June and as late as December in light

traps at Tifton, Georgia. Generally there are two periods of abundance,

one in June and another in August to early September (3, 7). Adults appear

from March to November in the Clemson area. Greatest numbers were observed

during the last week of July or the first week in August (49). In Cuba,

the spittlebug is found in greatest numbers during September, October, and

November (11). Adults have been taken in New England from the last week

in July until the latter part of September (47).

Habits

The Adult

Locomotion.--Adults are only moderately active and it is possible to catch

them by hand (7). Cardin (11) states that they fly rapidly from 2-5 meters

when disturbed. On two occasions, spittlebugs were observed to fly in ex-

cess of 100 feet in a single flight (49).

Feeding.--Cardin (11) reported that the adult feeds in the same way as the

nymph, by sucking the juices at the base of the plant. Hume (34) described

the adult feeding on holly which caused the leaves to turn yellow and drop.

Byers and Wells (9) demonstrated that both the nymphs and adults probe into

the xylem of host grasses.

Effects of environment on activiLies.--Cardin (11) states that the insect






- 10 -


is active at night and can be taken by light trap. Many authors have re-

ported P. bicincta in light trap collections (3, 7, 23, 24, L9, 50). In

the field, adults are most easily found in the morning when dew is on the

grass. Later in the day they seek shelter deep in the grass (7, 11).

Beck (3) states that no attempt has been made to associate activity with

weather conditions.

Mating and oviposition.--Caged pairs first mated when the female was $ to

9 days old. Pairs were observed mating 1 to 4 times during the second

week of adult life. Females evidently mate before and after oviposition

begins and oviposition begins 1 to h days after mating. The average ovi-

position period was 14 days (7). According to Cardin (11) eggs are laid

on the soil, very close to the host grass. Beck (3) found eggs behind

leaf sheaths of grasses and inserted between the inner and outer epidermis

of the leaf sheath. Other investigators found eggs inserted into the stem

occasionally and most frequently deposited in the soil or trash around the

base of the plant (7, 49).

Number of eggs and fertility.--A single female under laboratory conditions

deposited 142 eggs (3). In the greenhouse, 60 females oviposited an aver-

age of 39.6 eggs (49). Byers (7) reports 50 caged females laid 0-170 eggs

per female with the average being 45.1. Beck (3) collected $29 eggs which

were 81.3% viable.

The Nymphal Instars

Immediately upon hatching, the nymphs make their way to a suitable

feeding site and start feeding (3, 7, 11, 49). The newly hatched nymphs

require a high humidity for survival until they begin feeding. Spittle

is produced within 5 minutes to an hour after feeding begins (7, 49). The

nymphs do not feed at one site all of their lives (7). Early instar nymphs






- 11 -


are found on the lower part of the plants near the roots, while the later

instars feed higher on the plant (11). The feeding sites of the nymphs

ranged from in. below to approximately 2 in. above ground level (h9).

Molting between instars takes place within the spittlemasses.

The Last Nymphal Instar

Transformation to the adult takes place within the spittlemass formed

at the last feeding site of the mature nymph. Ball (2) and Pass and Reed

(h9) described the manner in which molting is accomplished; the nymphal

skin splits over the top of the head and thorax and the adult crawls out.

The general adult rests inside of the spittlemass until the wings harden.

Overwintering

The two-lined spittlebug overwinters in the egg stage in Georgia (7),

South Carolina (49), and Florida (91).

Methods of Distribution

Although data on dispersal are lacking the insect is probably capable

of long-range travel by the wind. Glick (29) captured adults at night at

500 feet elevation using an airplane sampling device.

Effect on Host

Injury Caused

Cardin (11) contended that the nymphal stage was more injurious than

the adult. Other investigators also stated that Coastal bermudagrass was

injured as a result of feeding of both the nymphs and the adults (3, h9).

Later experiments revealed that only the feeding of the adult causes in-

jury to the grass through the injection of phytotoxic salivary substances

(9). Furthermore, neither the age nor the sex of the adult after the first

day is a factor in the ability of the insect to produce phytotoxemia (8).

A significant reduction in the quantity of roots and sod reserves is






- 12 -


caused by sustained spittlebug damage (58). Damage by P. bicincta is

believed to be important in relation to subsequent weed invasion of im-

proved pastures (28). Infestations of the two-lined spittlebug cause

serious nutritive depletions in grass (31). Extensive damage lowers the

palatability and may reduce or destroy a stand of pangolagrass (31).

Symptoms develop on Coastal bermudagrass within 1-3 days after adults

begin feeding. The first symptoms appear as white stippled areas arranged

in broken rows. Later these stippled areas coalesce to form streaks.

Continued feeding causes the leaf to turn brown and die. The severity of

damage is directly proportional to the length of time the adult feeds (9).

Parts Affected

Byers and Wells (9) reported that bermudagrass could be completely

top killed and new growth would be initiated from below ground.

Taliaferro et al. (58) found that spittlebug damage significantly reduced

root production and sod reserves but this reduction was primarily a func-

tion of the cessation of photosynthesis and other essential life processes

in the top growth. Histological studies indicate that the nymphs and the

adults feed in the xylem. The toxin appears to move both up and down the

stem in the xylem and excapes through the border parenchyma into the

mesophyll in the leaves where it causes loss of chlorophyll and, later,

death of both parenchyma and mesophyll (9).

Control

Natural Control

Bromley (6) recorded an asilid, Erax rubibarbis Macquart, preying on

TomaspiE bicincta in Massachusetts. Wray and Brimley (9h) found specimens

of Monecphora bicincta as victims of pitcher plants in North Carolina.

These are the only records of parasites or predators of any of the life

stages reported in the literature.






- 13 -


Cultural Control

Beck (3) observed that burning Coastal bermudagrass in April gave

100% control in Georgia. Mowing and raking also reduced the nymphal

population. From these observations, he concluded that the insect may be

substantially controlled by good pasture management and efficient use of

the grass as forage. Hodges et al. (31) suggests heavy grazing or making

hay or silage of spittlebug infested pangolagrass as a means of control-

ling or reducing the damage by spittlebugs. Apparently burning injures

pangolagrass (31).

Chemical Control

Genung (25) obtained good control of P. bicincta with 3 Ib AI/acre

of toxaphene in 100 gallons of water. McCaleb and Hodges (40, 41) got

no control with toxaphene, dieldrin, methoxychlor, or parathion at 2 lb

Al/acre.

Control of the nymph.--Pass and Reed (49) applied 11 insecticides to

Coastal bermudagrass 15 inches high and obtained no significant control

of the nymphs. However, they found that Guthion, endosulfan, endrin, and

DDT sprays at 0.5, 0.5, o.25, and 1 lb AI/acre, respectively, gave good

control of nymphs in 2 inch high bermudagrass stubble. In another ex-

periment, good nymphal control was obtained in tall grass with granular

heptachlor and endosulfan at 0.5 Ib Al/acre.

Byers (7) found that granular endosulfan, phorate, and lindane at

1-2, 0.5, and 0.25 lb AI/acre, respectively, significantly controlled

the nymphs.






- 14 -


Materials used against the nymphs and their effectiveness.


Signifi-
Lb chance of Percent Refer-
Treatment AI/acre control control ence


Azodrin EC

Carbaryl
Carbaryl
Carbaryl G

Carbophenothion
Carbophenothion

Dasanit G

DDT
DDT

Diazinon G
Diazinon G
Diazinon G
Diazinon G

Dimethoate
Dimethoate EC

Di-Syston

Dyfonate G

Endosulfan
Endosulfan
Endosulfan
Endosulfan
Endosulfan

Endrin
Endrin

Ethion G

Furadan G

Guthion
Guthion

Heptachlor G


0.6


1.0
1.0


0.5
0.5
1.4
2.2

2.0
0.5

2.0

1.0

0.5
0.5
0.5
0.5
1.0

0.25
0.25


7
91

7

91

3
49
49
49
7,10

49
49


1.0

1.0


Malathion






15 -

Materials used against the nymphs and their effectiveness (Continued).


Signifi-
Lb chance of Percent Refer-
Treatment AI/acre control control ence

Meta-Systox-R G 0.5 h9

Methoxychlor 1.0 67 h9

Mevinphos G 0.25 h9
Mevinphos G 0.25 h9

Naled 1.0 58 h9

Parathion 0.5 60 h9
Parathion G 1.0 52 91

Phorate G 0.5 3
Phorate G 2.0 + 7
Phorate G 2.0 100 91

Station G 1.0 48 91
Station G 1.4 56 91

Zinophos 0.5 3


aBlank space means no information was available.


that the treatment was not
at the 5% level.


significantly different from the


cMeans that the treatment was significantly different from the check
at the 5% level.

Control of the adult.--Pass and Reed (49) found that Guthion, malathion,

mevinphos, endosulfan, carbaryl, parathion, naled, and methoxychlor applied

as sprays at 0.5, 1, 0.25, 0.5, 2, 0.5, 1, and 1 lb AI/acre, respectively,

controlled adult spittlebugs caged over grass.

Byers (7) found that sprays of endrin, lindane, and methoxychlor at

0.125, 0.25, and 1 lb AI/acre, respectively, controlled the adults.

Strayer (57) suggested toxaphene, carbaryl, and Phosdrin at 1.5-2.0,

1.5-20, and 0.5 lb AI/acre for spittlebug control in Florida.


bMeans
check






- 16 -


Materials used against the adults and their effectiveness.


Signifi-
Lb chance of Percent Refer-
Treatment AI/acre control control ence

Azodrin EC 0.6 a 84 91

Carbaryl spray 2.0 +b 100 49
Carbaryl G 3.0 51 91

Dasanit G 1.6 72 91

Dimethoate EC 2.0 c 7
Dimethoate EC 0.5 84 91

Di-Syston G 2.0 7
Di-Syston G 2.0 23 91

Diazinon G 1.5 51 91
Diazinon G 2.2 72 91

Dyfonate G 2.0 69 91

Endrin spray 0.125 + 7

Endosulfan spray 0.5 + 100 h9
Endosulfan spray 0.25 85 7
Endosulfan spray 0.5 14 7
Endosulfan spray 1.0 85 7
Endosulfan spray 1.0 0 7

Fenthion G 2.0 46 91

Furadan G 1.0 23 91

Guthion spray 0.5 + 100 h9

Lindane spray 0.25 + 7
Lindane G 0.25 100 7
Lindane G 0.5 100 7
Lindane G 1.0 100 7
Lindane G 2.0 100 7

Malathion spray 1.0 + 100 h9

Methoxychlor spray 1.0 + 83 h9
Methoxychlor spray 1.0 + 7

Mevinphos spray 1.0 + 100 h9






- 17


Materials used against the adults and their effectiveness (Continued).



Signifi-
Lb chance of Percent Refer-
Treatment AI/acre control control ence

Mobam G 2.0 3 91

Mocap G 2.0 15 91

Naled spray 1.0 + 94 49

Parathion spray 0.5 + 94 49
Parathion G 2.0 10 91

Phorate G 0.5 99 7
Phorate G 1.0 81 7
Phorate G 2.0 +
Phorate G 2.0 87 91
Phorate G 1.0 78 91

Station G 1.4 67 91
Station G 1.0 31 91


aBlank space means no information was available.

bMeans the treatment was significantly different
5% level.


from the check at the


cMeans the treatment was not significantly different from the check
at the 5% level.















MATERIALS AND METHODS


Rearing

Eggs were collected for laboratory work following the methods devel-

oped by Beck (3) and Byers (7). Females caged on grass in 1 quart ice

cream cartons inserted their eggs into moist filter paper (Figure 1).

Eggs were removed and placed in 9 cm petri dishes on filter paper, then

kept continually moist under greenhouse conditions until hatching.

Nymphal studies were conducted in the field and greenhouse. Nymphs

were reared using the method described by Byers and Wells (9). Attempts

to rear the nymphs in the greenhouse indicated that unless the humidity

is maintained at a high level the young nymphs will not survive. In

determining the nymphal instars, head capsules were measured across the

outer margins of the eyes and the mesothoracic wing pads were measured

from the posterior edge of the pronotum to the posterior tip of the pads.

Virgin female spittlebugs were easily collected in the field in the

early morning by removing them from spittlemasses where they had emerged

as adults. Adults mated readily and were easily maintained in 1 quart

ice cream carton cages or larger screen wire cages.

Light Trapping

Light traps were omnidirectional in coverage and used 15-w General

Electric F1lT8 Dlacklight BL fluorescent lamps. They were of the general

purpose type described by Hollingsworth et al. (32) and purchased from

Ellisco, Inc., Philadelphia, Pennsylvania. Except when otherwise stated,


- 18 -









- 19 -


Figure 1.--Female two-lined spittlebugs caged on grass inserted their
eggs into moist filter paper wrapped around the grass.


. ...... ...i-;ii* F~ L'

A ik






- 20 -


light traps were placed on stands with the center of the light source h8

in. above the ground. The spittlebugs were trapped and preserved in 70%

isopropyl alcohol.

Height of Traps

The bidirectional trap consisted of a 15-w, blacklight lamp mounted

parallel to the ground in a common bathroom type fluorescent unit (Wire-

mold Company, Hartford, Connecticut). A 15 in. long, 2 in. deep enamel

pan filled with alcohol was placed under the lamp to act as a trap. Plac-

ing an omnidirectional trap at heights lower than 36 in. necessitated dig-

ging a hole and caused undue awkwardness in handling the collection con-

tainer which is below ground level.

Traps Using Different Colored Lamps

The effectiveness of various colored lamps in attracting spittlebugs

was evaluated using h standard omnidirectional light traps placed in a

straight line 50 ft apart. Five colors of General Electric Fluorescent

Lamps were used in the tests. The colors were rotated so that each had

an opportunity at each trap position.

Periods of Flight Activity

To determine the periods of nocturnal adult activity, a light trap

which divided the catch into hourly samples was utilized (Figure 2). It

was a modification of a design by King et al. (36). The timer was a 60

Minute Cycle Electric Timer (Supreme Electric Products Co., Rochester, New

York). The magnetic solenoid was out of an automatic clothes washer. The

turn table was powered by the gravitational pull derived from a pully and

weights. The light was centered 48 in. above the ground.

Sticky Board Traps

Wilson and Shade (93) reported on the possible use of colored sticky






- 21 -


boards as a survey tool for meadow spittlebug. The Florida study was

conducted at the Everglades Experiment Station. Boards measuring 12 in.

by 12 in. were cut from 1 in. masonite and painted with several coats of

paint. Four colors were used: white, green, yellow, and lemon-yellow.

These colors were matched to plates from Maerz and Paul (39) and the

classification for each shade is given in Table 6. Two boards of the same

color were attached to the ends of a stick 1 in. by 1 in. by 2 ft so that

the sides of the board at one end faced North and South while those at

the other end faced East and West. The boards and crossbar were attached

to 2 in. by 2 in. by 8 ft stakes in the field at heights of 3 ft and 6 ft.

A thin layer of Stickem (Michel and Pelton Co., Emryville, California)

was then applied to the boards to trap the insects. The experiment was

designed as a randomized block with the traps 50 ft apart in rows 50 ft

apart.

Grass Varieties Trial

Nineteen grasses were planted on June 7, 1968, in a well established

pangolagrass pasture that had received spittlebug damage the previous

year (Table 8). Each grass was replicated h times in a randomized block

design. In each replication, h clumps of grass, 6-8 in. in diameter, were

planted 1 ft apart in the pangolagrass sod. It was assumed that spittle-

bugs had an equal opportunity to feed on and damage all of the grasses.

Pangolagrass was used as the standard for comparing spittlebug injury.

Dr. S. C. Schank provided the Digitaria crosses and the other grasses came

from the grass introduction nursery at the Range Cattle Station.

Chemical Control

All experiments were conducted in randomized complete block designs.

Unless stated otherwise, materials were applied with a Kiekens Whirlwind







- 22 -


Figure 2.--Light trap, which divided the catch into hourly samples, used
to determine periods of two-lined spittlebug activity.








- 23 -


.. .. "..... ;..;. iiii.. i i:i:.

,'"

























































Figure 3.-Gasoline powered knapsack blower used to apply materials in
the chemical control experiments.






- 2h -


Holland Model KWH-25 (Vandermolen Export Co., North Caldwell, New Jersey),

a gasoline powered knapsack blower which delivers both wet and dry formu-

lations (Figure 3).

Adults were sampled by making 20 sweeps in each plot. Nymphs were

sampled using a 1 ft2 metal frame. All the spittlemasses within this

perimeter were counted in 5 randomly chosen spots in each plot and ex-
2
pressed as the number of spittlemasses per ft More than 1 nymph per

spittlemass is common, but for convenience, spittlemasses were counted

rather than nymphs. Duncan's multiple range test was used to determine

significant differences between treatments.

Experiments were conducted at 2 locations in Florida: the Everglades

Experiment Station at Belle Glade on St. Augustinegrass, Stenotaphrum

secundatum (Walt.) Kuntze; and the Range Cattle Experiment Station at Ona,

on pangolagrass, Digitaria decumbens Stent.

The chemical definitions of insecticides used for which there are

no common names are:

Bayer 37289, 0-ethyl 0-2,4,5-trichlorophenyl ethylphosphonothioate

Baygon o-isopropoxyphenyl methylcarbamate

Dasanit 0, 0 -diethyl 0- p-(methylsulfinyl)phenyl] phosphorothioate

Dursban, 0, O-diethyl 0-3,5,6-trichloro-2-pyridyl phosphorothioate

Dyfonate 0-ethyl S-phenyl ethylphosphonodithioate

SupracideO, 0-0-dimethyl phosphorodithioate S-ester with h-(mercaptomethyl)
-2-methoxy-A 2-l,3,4-thiadiazolin-5-one

Mobam benzo(b)thien-h-yl methylcarbamate

Mocap, 0-ethyl S,S-dipropyl phosphorodithioate

UC-30045, methyl 2-isopropyl-h-(methylcarbamoyloxy) carbanilate

VCS-506, 0-(2,5-dichloro-4-bromophenyl) 0-methyl phenylthiophosphonoate

ER-2h41, formula not available






- 25 -


1967 Experiments

All of the experiments were conducted in pangolagrass pastures at

the Range Cattle Station. In most of the experiments, the treatments

and checks were replicated 4 times. The grass was generally 12-15 in.

high at the time of application. Sprays were applied at the rate of 35

gal of water per acre. Specifics for each experiment are as follows:

Experiment l.--Overwintering eggs apparently do not hatch until

moisture is adequate. Newly hatched nymphs tend to wander for a short

time in search of feeding sites and should be susceptible to residual

insecticides. Chlordane 10% G, dieldrin 10% G, and parathion 10% G, were

applied at rates of 3 lb AI/acre with a tractor-mounted cyclone seeder in

plots 18 ft by 250 ft. Nymphs were counted 33 days after application and

the results are summarized in Table 9.

Experiment 2.--The purpose of this experiment was to determine if

mowing or mowing plus insecticides cleared for use on pastures would con-

trol spittlebug nymphs. Seven treatments were applied in plots 15 ft by

15 ft (Table 10). The mowed plots were cut h in. high with a power lawn

mower and the grass removed. Spittlemasses were counted 3 and 7 days after

treatment.

Experiment 3.--Four rates of azinphosmethyl EC were applied in plots

25 ft by 25 ft (Table 11). Counts were taken 3, 6, and 16 days after

application.

Experiment h.--The purpose of this experiment was to test the effec-

tiveness of eight experimental insecticides for controlling spittlebugs.

The treatments and a check were replicated 3 times in plots 15 ft by 40 ft

(Table 12). Adults were sampled 2 and 12 days after application and nymphs

at the 3 and 12 day intervals.





- 26 -


1968 Experiments

Five experiments were conducted in 1968. Plots measured 25 ft by

50 ft in all but the first experiment. Experiments 1, 2, and 3 were con-

ducted on 10-12 in. high St. Augustinegrass and the last 2 experiments

were conducted on 24-36 in. high pangolagrass.

Experiment l.--This experiment was designed to test the effectiveness

of h rates of phorate 10o G against spittlebug nymphs and adults. Treat-

ments and the check were replicated 3 times in plots 25 ft by 25 ft (Table

14). The adult population was sampled 1 and 7 days after application.

Nymphs were sampled at intervals of 2, 7, lh, 20, 27, and 57 days follow-

ing treatment. Precipitation totaled 1.52 in. within h8 hr after applica-

tion.

Experiment 2.--The 2nd experiment was designed to evaluate the effec-

tiveness of certain insecticides currently used on pastures and vegetables.

Seven treatments and a check were replicated h times (Table 16). In pre-

vious experiments, spray treatments apparently did not reach the nymphs

and gave little control. A spreader, Triton X-100, was added at the rate

of 3 oz/100 gal of water to 2 treatments in an attempt to increase their

effectiveness. The 2 treatments containing Triton X-100 were applied in

100 gal of water/acre and all others at 30 gal/acre. No precipitation

was recorded for 3 days after the applications. The population was sam-

pled 1, 4, 8, and 12 days after application.

Experiment 3.--In this experiment the effectiveness of a number of

experimental materials was determined for controlling two-lined spittle-

bugs on St. Augustinegrass. Eight treatments and a check were replicated

h times (Table 17). There was 1.09 in. of precipitation during the first

2h hr after application. The adult population was sampled 3 and 11 days






- 27 -


after application. Nymphs were sampled at intervals of 3, 11, 20, and 34

days after treatment.

Experiments h and 5.--These experiments were conducted on ungrazed

pangolagrass pastures. The grass was thickly matted near the ground and

provided an optimum environment for spittlebugs. The first rain fell 5

days after application (1.97 in.). The heavy top growth of the grass

prohibited sampling of adults by sweep net. Control of the adults was

estimated indirectly through visual observations of damage to the grass.

Visual rating of the different treatments were made on October 11, 36 days

after application (Tables 20 and 22). This was after the spittlebug popu-

lation had declined but before any frost damage occurred. Nymphs were

sampled 6 and 13 days after application.

Seven insecticides and a check were replicated 3 times in the hth

experiment (Table 19).

In the 5th experiment, 7 insecticides and a check were replicated

h times (Table 21).















RESULTS AND DISCUSSION


Biology and Ecology

Eggs

Description.--Newly deposited eggs are bright yellow and more pointed at

the anterior than the posterior end. Fifty eggs averaged 1.02 mm in length

(range 0.96 mm to 1.06 mm) and 0.35 mm in width (range 0.32 mm to 0.37 mm).

There is no evidence of a micropyle in the chorion of the egg. A faint

longitudinal "hatching line" is visible on new eggs from the anterior tip

to about the middle of the egg. This area gradually darkens for 5 to 6

days, then a black "hatching lid" splits the chorion and protrudes until

the egg hatches (Figure h). Eggs 12 to 15 days old have a red spot on

each side of the "hatching lid" and also on each side of the posterior

end. These red areas later coincide with the red eyes and the 2 red areas

on the abdomen of the nymph.

Hatching.--Eggs held at 22.20-2h.h0 C on moist filter paper hatched in

16-21 days (mean of 19 days). At hatching the black lid breaks away and

the nymph emerges head first and ventral side uppermost. Most eggs hatched

at night which is probably an adaptation to reduce the hazard of desicca-

tion for the newly emerged nymph.

Location.--Caged females show a strong tendency to insert their eggs rather

than dropping them at random. Most eggs were inserted into moist filter

paper and rarely into the stems or leafsheaths of the grass. In the field,

eggs are produced singly but many eggs may be found in one location. They


- 28 -






- 29 -


Figure I.--Development of Prosapia bicincta eggs. From left to right
the eggs are 1, 12, and 19 days old (hatched).
(Figure 32 times actual size).






- 30 -


are deposited in the moist litter and debris at the base of grasses.

Because of the low searching range of the 1st instar nymph-and its

susceptibility to deiccation, the female chooses an oviposition site

which will provide an optimum high humidity and protection. During months

of high rainfall (June-August) and rapid grass growth, eggs are deposited

throughout the field. Then, as dry weather approaches in the fall females

seek the moist environment provided by bunch grasses (vaseygrass, smutgrass,

bristlegrass)and low areas. It is in these locations that most of the

overwintering eggs are deposited. Not only do the bunch grasses provide

protection by the nature of their growth but they are also among the most

unpalatable of the pasture grasses and the least likely to be grazed short

during the winter.

Overwintering and the effects of moisture.--During the dry season (October

to April) soil moisture in Florida is very low and the spittlebug popula-

tion overwinters in the egg stage. Eggs were collected from caged females

from June to October. When held on moist filter paper under greenhouse

conditions, eggs collected from June to August hatched in 16-21 days. One

hundred thirty-five eggs collected from September 29 to October 8, 1968,

failed to hatch under these same conditions and after 30 days and were con-

sidered in diapause. This suggests that eggs oviposited by fall females

enter diapause regardless of environmental conditions in the field. What

physiological mechanisms induce the fall females to produce diapausing

eggs was not ascertained.

These eggs were then held on dry filter paper at 220-2h C for 135

days. Upon remoistening, 75% of the eggs hatched in 16-19 days. There-

fore, diapause was terminated only by long exposure to dry conditions.

This has been reported for the sugarcane froghopper, Aeneolamia varia






- 31 -


saccharina Distant (19). The exact number of days under dry conditions

needed to break diapause was not determined.

In the field, eggs first hatch in the spring in low areas where mois-

ture is evident. At Ona, during May, 1968, 2-3 weeks before hatching

occurred in the field, nymphs were abundant in a strip of St. Augustine-

grass kept moist by a septic tank drain. Temperature is undoubtedly

important, but diapausing eggs evidently will not hatch unless moisture

is adequate. This condition quite possibly results in a synchronous

hatching of eggs at the onset of the wet season.

Exposing nondiapausing 1-2 day old eggs to dry conditions delayed

hatching. For example, when eggs were dried 8 days, then moistened, they

hatched in 2h-29 days. When eggs in which the "hatching lid" had split

the chorion (6-7 days old) were dried, all of the eggs died. Apparently

after the chorion is split the eggs are no longer able to resist dry

conditions.

Nymphs

One of the most precarious periods in the life of the two-lined

spittlebug is from the time the "hatching lid" splits the chorion of the

egg until the newly emerged nymph begins to feed. Eggs and nymphs are

very susceptible to desiccation during this period. After the nymph be-

gins to feed, it creates its own micro-climate and is therefore protected

from desiccation. Upon hatching, the 1st instar nymph seeks a suitable

feeding site. It probes in several spots before the mouth parts are

finally inserted and a spittlemass is produced. The manner in which the

spittlemass is produced is described in detail by Weaver and King (92).

This same article reviews the theories proposed to explain the source of

the material which gives the spittlemass its remarkable stability. Nymphs






- 32 -


are not confined to one site but move about, especially following molting.

Their movements should render them susceptible to residual insecticides.

In the field, the first nymphs in the spring and the last in the fall

are found on dense growing clump grasses. The thick foliage provides pro-

tection from drying winds and high temperatures which results in a higher

survival rate of newly emerged nymphs. Later instars (3rd-5th) seem to be

able to withstand lower humidities than the earlier ones.

One to 6 nymphs, sometimes in different instars, have been observed

in a single spittlemass. The 3rd instar produces an easily visible spittle-

mass and is commonly the first one observed in the field. Stems and runners

of grass at ground level are favored feeding sites of the nymphs. During

wet periods, nymphs crawl up stems to avoid drowning. There, they produce

a spittlemass and remain until surface water recedes.

Description.--Molting between instars takes place within the spittlemass.

Five instars were recognized in this study based on the number of molts

observed during rearing and measurements taken of the head capsules and

mesothoracic wing pads of both reared and field collected nymphs. Body

length was found to be a poor indicator of instars. Measurements from 150

nymphs are summarized in Table 1. First instar nymphs did not have mea-

surable wing pads. Neither Byers (7) or Washbon (91) distinguished between

the true 1st and 2nd instars. Their descriptions of the "2nd,, "3rd",and

hth," instars correspond to the true 3rd, th and 5th, instars. The 5

instars are shown in Figure 5.

Duration of nymphal stages.--Two-lined spittlebug nymphs were difficult to

rear. First instar nymphs were especially susceptible to desiccation so

proper humidity was very critical for rearing. Later instars (3rd_-th)

brought in from the field were easier to maintain. Nymphs reared in the






- 33 -


greenhouse during July averaged 8, 8, 10, 12, and 12 days for the 1st, 2nd,

3rd, th, and th instars, respectively. The nymphal stage averaged 50

days.

Host plants.--Adults can probably survive on almost any plant that provides

succulent foliage. So only those plants on which the nymphs develop are

considered the true hosts. Because of the low searching range of the 1st

instar nymphs, females probably oviposit on or near plants that will make

suitable hosts.

Nymphs have been recorded on 40 plants in Florida (Table 2). These

were predominantly grasses on which the adults also commonly feed. Two

woody hosts are reported in the literature. Due to the predominance of

grasses and grass-like plants, there is some question as to the validity

of gebera and Barbados cherry as nymphal hosts. This list was compiled

from the literature as well as from personal observations. Citation of

a plant species by several authors indicates that it probably is a favored

host.

Adults

The 5th instar nymph changes in appearance about 2h hours before the

final molt as the reddish bands of the adult become visible through the

nymphal exoskeleton. Transformation to the adult takes place within the

spittlemass formed at the last feeding site of the 5th instar nymph. The

nymph often crawls several inches up a stem and feeds long enough to form

a spittlemass. Ball (2) first described the manner in which molting is

accomplished; i.e., the nymphal skin splits over the top of the head and

thorax and the adult crawls out. Most adults emerge in the early morning,

rest within the spittlemass until the wings harden, and depart before

noon.















X


E'- r-A

















-4 ~
tac


ti)












.4-' 4-

En~
ID






ca























4-1 c
0 1"
u)


Uy,"




























"-4














IU


Li)


- 35 -






- 36 -


Table l.--Head capsule and mesothoracic wing pad measurements (in mm) of
the nymphal instars of Prosapia bicincta in Florida.


Mean Mean
head wing pad
Instar width Range length Range


I 0.34 0.32-0.37

II 0.61 0.57-0.69 O.14 0.12-0.15

III 0.98 0.94-1.02 0.31 0.29-0.35

IV 1.51 1.42-1.63 0.82 0.79-0.84

V 2.16 2.01-2.25 2.50 2.40-2.55

Imago 2.32 2.25-2.40






- 37 -


Table 2.--Host list of Prosapia bicincta nymphs in Florida.


Common name and reference


Andropogon capillipes Nash

A. nodosus (Willem.) Nash

A. virginicus L.

Brachiaria humidicola (Rendle) Schw.

Chloris petraea Swartz

Cynodon dactylon (L.) Pers.

Cyperus distinctus Steud.

C. globulosus Aubl.

Digitaria decumbens Stent

D. gazensis Rendle

D. pentzii Stent

D. sanguinalis (L.) Scop.

D. setivalva Stent

D. swazilandensis Stent

D. valida Stent

Eleusine indica (L.) Gaertin.

Eragrostis curvula (Schrad.) Nees

Eremochloa ophiuroides (Munro) Hack.

Eriochloa polystachya H.B.K.

Gerbera jamesoni Hook

Hemarthria altissima Stapf & Hubb.

Malpighia glabra L.


bluestem, chalky*

bluestem 27

bluestem, broomsedge*

grass*

chloris, stiffleaf*

grass, bermuda*,4%2,91

sedge*

sedge*

grass, pangola*,62,91

grass*

grass*,27

grass, hairy crab*

grass 27

grass 27

grass*,27

grass, goose*

grass 27

grass, centipede h2

grass, carib 91

gerbera 61

grass*

cherry, Barbados 59


Scientific name


___ ~_






- 38 -


Table 2 (Continued)


Scientific name


Common name and reference


Panicum antidotale Rentz.

P. coloratum L.

Panicum hemitomon Schult.

P. maximum Jacq.

P. purpurascens Raddi

P. repens L.

P. virgatum L.

Paspalum notatum Flugge

P. plicatulum Michx.

P. urvillei Steud.

Pennisetum ciliare (L.) Link

Rhynchelytrum
roseum (Nees) Stapf & Hubb.

Saccharum officinarum L.

Setaria geniculata (Lam.) Beauv.

Sorghum vulgare Pers.

Sporobolus
poiretii (Roem. & Schult.) Hitchc.

Stenotaphrum
secundatum (Walt.) Kuntze

Zea mays L.


grass 27

grass 27

maidencane*

grass, guinea*,91

grass, para*,91


grass,

grass,


torpedo*

switch*


grass, bahia*

grass*

grass, vasey*,87

grass 27


grass, natal*

sugarcane*

bristlegrass*

sorghum*


grass, smut*

grass
St. Augustine*,62

corn 91


-Personal observation


__






- 39 -


Description.--The general adults are white except for the red bands on the

wings and pronotum. They attain the mature coloration within hours.

Doering (15) differentiated P. (=Tomaspis) bicincta from other related forms

according to the following family, generic, and specific characters. The

antennae are inserted on the genae between the eyes. There are only 2

stout spines and crown of spines around the apex of the hind tibia. The

anterior margin of the pronotum is straight and the head is narrower than

the pronotum. The apex of the tegmina is distinctly reticulated. Dorsally

the adult is dark brown to black with a narrow orange or red transverse

band across the humeral angles of the pronotum and 2 slightly wider bands

across the tegmina. Fennah (17) illustrated the genitalia of the male.

A dorsal view of the adult is pictured in Figure 6.

Fennah (17) calls the dark form a geographical subspecies occurring

in the New England area. In 2 years of light trapping throughout Florida

it was not uncommon to collect adults with one line missing or devoid of

lines (Figure 6). This suggests that the dark form is nothing more than

a color phase and not a geographical subspecies.

Feeding and mating habits.--Adults are more active at night and on cloudy

days. During sunny days their habitat is similar to that of the nymphs;

i.e., under the canopy of grass next to the soil surface.

Adults readily mate in cages. In the field, mating usually was ob-

served in the grass near the ground. Mating was observed at all times

during the day and throughout the growing season. Some females of mating

pairs captured in the field contained developed eggs, others did not.

This indicates that females mate both before and after oviposition begins.

Caged females were observed mating more than once.

Caged virgin females, 2-6 days old, produced a perfume-like odor that






- h0 -


was very detectable, especially during mornings. On one occasion 2 field

collected males were placed with 2 five day old virgin females. Mating

took place immediately. However, the exact nature and function of the

odor was not ascertained.

Fecundity and longevity.--Eggs were collected from caged females from June

to October. Caged females began ovipositing when 7 days old and the aver-

age oviposition period was lh days. Females laid from 0-1h2 eggs with the

average being 50.3. Of 3h9 eggs collected from caged females in July, 9h%

were viable. Caged females in the greenhouse lived an average of 21 days.

Predators and Parasites

No parasites or predators of the eggs or nymphs were found in this

study or have been recorded in the literature for P. bicincta.

W. G. Genung (unpublished data) found remains of the two-lined

spittlebug in the stomachs of 8 southern meadow larks, Sturnella magna

argulata (Bangs), at Belle Glade. Presumably many other birds capture

spittlebugs. However, Washbon (91) was unable to find their remains in

8 cattle egrets, Bubulcus ibis ibis (L.), killed in September at Belle

Glade. Genung also has observed the adults in the webs of the garden

spider, Argiope aurantia Lucas, and the golden silk spider, Nephila

clavipes (L.). Finally he recorded the reduviid, Zelus bilobus (Say), as

a predator.

Many spittlebugs were collected in light traps throughout the season

with mites attached to them. Individual adults had up to 6 mites attached

mainly to the legs and wing covers. Most of the mites were Leptus sp.

(Trombidiformes: Erythraeidae). One specimen of Clavidromus transvaalensis

(Nesbitt) (Mesostigmata: Phytoseiidae) was collected. The mites were iden-

fied by H. A. Denmark of the Florida State Department of Agriculture,









- 1 -


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- h2 -


Division of Plant Industry, Gainesville.

W. G. Genung (personal communication) has observed a parasitic fungus

attacking adult spittlebugs and greatly reducing the population at Belle

Glade. Several specimens of adult spittlebugs killed by the fungus were

collected at Belle Glade on October 2, 1967. Dr. L. R. Batra of the USDA

Crops Production Research Branch, ARS, Beltsville, Maryland, identified

the fungus as Entomophthora grylli Fresenius. The infected insects climb

as high as they can on grass stems and weeds and attach with their heads

pointing upward. After death, which occurs while they are in these ele-

vated positions, they "mummify" and their bodies remain hanging for several

days.

The first parasitized adult was found on June 26 in 1968 at Belle

Glade. Later the fungus appeared at the Range Cattle Experiment Station

with adults being killed in apparently epidemic numbers. Hundreds of

parasitized adults were seen in the field on September 19 attached to

many grasses and weeds (vaseygrass, bahiagrass, smutgrass, bermudagrass,

pangolagrass, sedges, and dog fennal). Collections made by sweep net,

which picked up both dead and live adults, indicated that approximately

5% of the population was controlled at that time by the fungus.

A review of the literature indicated that investigators had been un-

able to culture E. grylli, so artificial innoculation of healthy spittle-

bugs was not attempted. However, cultures of 2 species of the genus,

Entomophthora coronata and E. apiculata, were secured from the USDA Insects

Affecting Man and Animals Laboratory, Gainesville. These fungi were main-

tained on Sabouraud Dextrose Agar.

The usual route of Entomophthora infection is by the penetration of

the integument, especially the thinner intersegmental areas of the body






- 43 -


wall and the appendages (56). On 2 dates, 10 adult spittlebugs were in-

oculated with each fungus by allowing them to walk on the cultural plate

and then caged on St. Augustinegrass. Only 1 kill was recorded. This was

by E. apiculata and occurred h days after inoculation.

Outbreaks of the fungus occur most commonly in August and September

in Florida. Warm humid or wet weather seems to be necessary to enable the

infection to develop. Steinhaus (56) recognized the destructiveness of

E. grylli in natural outbreaks, but states that it is too dependent upon

optimum conditions of temperature and moisture to be a practical means of

artificial control.

Life Cycle

The duration of the life cycle undoubtedly is influenced by environ-

mental factors, especially temperature. Eggs probably develop slowly in

the spring due to cool nights. However, at 22.20-2h.ho C about 19 days

are needed for the eggs to hatch. Under greenhouse conditions the nymphal

period lasts about 50 days. Females begin ovipositing when 7 days old,

giving a total of 76 days for the life cycle from egg to egg.

Depending upon temperature and precipitation most of the overwinter-

ing eggs hatch from late March to late April. The 1st generation adults

are then abundant in June. The adult population peaks again in early

August to early September and this generation deposits overwintering eggs.

The adult population of the last generation is greatly reduced by late

September probably due to the fungus disease and the decrease in succulent

grasses caused by the approaching dry season. Although the two-lined

spittlebug overwinters in the egg stage, an occasional adult has been

taken as late as November 25 in Gainesville. W. G. Genung (personal com-

munication) has collected an occasional adult by light trap at Belle









Glade during January and February. The last adults observed in the fall

are usually females.

Although there seems to be a somewhat synchronous hatching of over-

wintering eggs in the spring, there is something in the physiology of the

eggs and nymphs that inhibits the development of members of a given gen-

eration. As a result, the life cycles of individuals are not equal and

2nd generation nymphs are soon confused with nymphs from overwintering

eggs. This behavior probably aids in maintaining the population by mini-

mizing the probability of a catastrophic event destroying the entire popu-

lation.

Light Trapping

The fact that the two-lined spittlebug is attracted to light has

been known for many years. Cardin (11) suggested using light traps to

control the adults in 1917. Beck (3) and Byers (7) used light trap catches

as indicators of population trends. Both reported that there were 2 peaks

of abundance during the year at Tifton, Georgia, one occurring in June and

the other in late August to early September. Light traps were used in

this study to determine the population abundance and flight activities

of P. bicincta in Florida.

Seasonal distribution.--The seasonal occurrences of adults in light traps

at Gainesville for the years 1966-68 are shown in Figure 7. There were 2

peaks in the population each year, one in June and another in late August

to early September. Although the 2 peaks probably represent 2 generations

per year, about 85 days occurred between the peaks in 1966, 60 days in

1967, and about 82 days in 1968. In 1966 the 1st adult was captured by

light trap on April 18 and the last on October 22; in 1967 the 1st was

collected May 6 and the last on October 23; and in 1968 the 1st was col-


- 44 -








































i e~ri~


200

150

100

0

0
100

80
60

40

20
0
600

500

400

300
200
100

0


1968


l 1o67




IjLLLDiW


Jun e


A u(. St pt


Figure 7.--Weekly occurrence of Prosapia bicincta in light trap
catches for three years at Gainesville, Florida.


LJUy
iM _y


- 45 -






- 46 -


elected May 12 and the last on December 2.

Figure 8 graphically shows the average weekly occurrence of Prosapia

bicincta in blacklight traps at the Range Cattle Station in 1967. Data

were incomplete with 2 weeks missing in July and none taken after the 3rd

week in June. An unusually dry spring apparently delayed adult emergence.

Consequently, the normal June peak was not observed.

Male spittlebugs make up a much higher percentage in light trap catches

than females. In those data represented in Figure 7, 99% were males in

1966, 77% were males in 1967, and 77% were males in 1968. Figure 9 typi-

fies the seasonal abundance broken down into sex. The number of females

captured remains quite low throughout the season but peaks in the female

population appear to be identical with that of the males. Field observa-

tions show the females to be much more secretive and less active than the

males which probably accounts for the low numbers in light traps.

Effectiveness of traps at various heights.--Table 3 summarizes data on the

effectiveness of light traps equipped with Blacklight BL lamps at different

heights for collecting Prosapia bicincta. Omnidirectional traps appear

to be more efficient than the bidirectional type. Traps placed with the

lamp centered 2h in. above the ground caught more spittlebugs than those

at h8 in. and h8 in. high traps did better than those 120 in. high. Re-

gardless of the type of trap used, the lower traps appear to capture a

slightly higher percentage of females than do the higher traps.

Effectiveness of light traps using different colored lamps.--Studies were

conducted at Belle Glade to determine the effectiveness of different col-

ored lamps in attracting spittlebugs to light traps. These data are sum-

marized in Table h. The Blacklight BL lamps attracted the most spittle-

bugs followed by Blacklight BLB lamps.








- 47 -


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- 49 -


Table 3.--Effectiveness of blacklight traps placed with their lamps
centered at various heights above the ground for attracting
Prosapia bicincta.


Male Female
No. No. % Total

Gainesville, 1967 Numbers captured in 15 nights

Omnidirectional trap 48 in. high 229 85 52 15 281
Omnidirectional trap 24 in. high 497 88 67 12 564
Bidirectional trap 6 in. high 72 77 12 23 94

Range Cattle Station, 1967 Numbers captured in 15 nights

Omnidirectional trap 120 in. high 168 90 19 10 187
Omnidirectional trap 48 in. high 530 93 41 7 571
Bidirectional trap 6 in. high 172 90 20 10 192

Everglades Experiment Station, 1968 Numbers captured in 5 nights

Omnidirectional trap 48 in. high 21,042 97 745 3 21,787
Omnidirectional trap 24 in. high 20,972 89 2,477 11 23,149






- 50 -


Periods of flight activity.--A light trap which divided the nightly catch

into hourly samples was used to determine periods of flight activity.

Table 5 summarizes the results from 9 nights at Belle Glade. Some spittle-

bugs were trapped during every hour of the night but about 71% of the total

were captured by 11 p.m. and 85% were taken by 12 midnight.

Figure 10 graphically depicts the flight activity of P. bicincta

according to sex. The activity of the females was similar to the male and

there was only 1 peak of activity per night for both sexes.

Effects of weather conditions on light trap catches.--As would be expected

weather conditions can greatly influence light trap collections of spittle-

bugs. The minimum night time temperature is one important source of varia-

tion. Figure 11 shows how minimum temperatures effect the nighttime ac-

tivity of P. bicincta as determined by light trap collections. In general,

catches are greatly reduced when the minimum temperature is below 650 F

and spittlebugs are rarely caught below 600 F. To have much effect on

the nightime activity, low temperature must occur within the h hour period

after sunset. Temperature probably influences spittlebug activity only in

May, September, and October.

Precipitation has little effect on catches except when it occurs be-

fore midnight. Rain during these hours can greatly reduce light trap

catches. For example, 3,10O spittlebugs were captured on June 12, 1968,

at Belle Glade; rain began the next day at dark and continued into the

night resulting in the capture of only 455 spittlebugs; the following

night the catch was back up to 2,h23.

No quantitative data were collected on the effect of wind velocity

or direction on light trap catches. However, strong winds should reduce

flight activity because the two-lined spittlebug is not a particularly





- 51 -


Table 4.--Effectiveness of colored General Electric F15T8 fluorescent lamps
in attracting Prosapia bicincta to light traps. Everglades Ex-
periment Station, Belle Glade, Florida, 1968.


Date and adults captured per night
Lamps
compared 6/11 6/12 6/13 6/17 Total

Blacklight BL 1080 3140 h45 2423 = 7098

Cool White 247 319 132 247 = 972

Gold 33 43 7 36 = 119

Red 2 6 2 0 = 10


6/18 6/19 6/20 6/26

Blacklight BL 4893 4700 8568 1089 = 24042

Blacklight BLB 2178 2584 6479 532 = 15543

Cool White 1967 1577 2960 210 = 7493








- 52 -


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strong flier.

Although the activity of the spittlebug has not been specifically

correlated with light intensity, it is not a crepuscular species and has

only one peak of activity per night. Also spittlebug catches in light

traps do not show any variations due to the effect of moonlight.

Effectiveness of Colored Sticky Board Traps

Sticky board traps were rather ineffective for trapping two-lined

spittlebugs (Table 6). Only 223 spittlebugs were captured in 26 days at

a time when the adult population was at a peak.

As might be expected from the light trap studies, most of the spittle-

bugs were trapped at night and nearly all were males. Because the adults

are most active at night, the color of the board probably had little if

any effect. The yellow boards trapped slightly more spittlebugs than the

other colors. No significant differences were detected between the direc-

tions that the sticky boards faced. A majority of the spittlebugs were

trapped at the 6 foot level which seems contrary to the finding that lower

light traps caught more spittlebugs. In general, the spittlebugs were

probably caught on the sticky boards only haphazardly during flight.

Description of Spittlebug Injury to Pangolagrass

Byers and Wells (9) proved that only the adults caused injury through

the injection of phytotoxic salivary substances. They described the pro-

gression of symptoms on Coastal bermudagrass. Age and sex were not im-

portant in the ability of the adult to produce injury (8).

P. bicincta is primarily a pest of pangolagrass in Central Florida.

Field observations in that area indicated it is the adult that damages

pangolagrass. Large populations of nymphs go unnoticed until the adults

emerge and cause injury.


- 55 -









To determine the progression of symptoms of spittlebug damage, indi-

vidual adults were confined about 6 in. above the soil on stems of potted

pangolagrass in the seed-head stage. This was replicated 12 times. Maerz

and Paul (39) color charts were used to determine the colors in the des-

cription.

Adults caused injury symptoms within 2h hours. Symptoms first appeared

on the blades immediately above the feeding site, then progressed to the

next highest blade. Injury to a single blade began at the terminal end.

The tip turned yellow (9-Kh) and this discoloration proceeded basally.

Yellowing was followed by the blade turning brown (19-J1) and curling.

Where the stem forked above the feeding site, only 1 fork showed symptoms.

The blades died in 1-3 days and the stem in 3-h days.

Effects of Damage on Nutritive Value of Grasses

Washbon (91) found that St. Augustinegrass damaged by the two-lined

spittlebug was about 20% lower in protein than undamaged grass. In August,

1968, grass was collected from areas of spittlebug damaged and undamaged

areas of the Range Cattle Station. Two samples from each area were weighed

in the field and oven dried for h8 hours. The wet weight was determined

and the samples were ground up in a Wiley mill. A standard proximal anal-

ysis was performed on the samples by M. M. Sharpe, Division of Chemistry,

State of Florida Department of Agriculture, Tallahassee. Table 7 summa-

rizes the results of that analysis.

Spittlebug damaged grasses contained less moisture on a wet basis

than uninjured grasses. This is reflected in the field by the brown dried

appearance of damaged grass. Spittlebug damaged grasses contained con-

siderably less protein than undamaged grasses. Damaged pangolagrass con-

tained about h5% less protein than the undamaged samples and about 17%


- 56 -









- 57 -


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- 58 -


Table 7.--Effects of damage by adult Prosapia bicincta on the nutritive
value of pangolagrass and bermudagrass.


Percentages on an oven dried sand free basis
Nitrogen-
% Moisture free-
Sample wet weight Moisture Protein Fat Fiber Ash extract

Undamaged Pangolagrass

I 63.9 5.0 4.9 2.0 31.9 4.0 52.2
II h5.0 5.2 4.5 1.5 33.5 3.6 51.7
Mean 59.0 5.1 4.7 1.8 32.7 3.8 52.0

Damaged Pangolagrass

I 40.2 5.4 2.6 1.3 30.4 4.3 56.0
II 41.4 4.7 2.6 1.h 31.2 4.0 56.1
Mean 40.8 5.1 2.6 1.4 30.8 4.2 $6.1

Undamaged Bermudagrass

I 64.1 5.1 9.8 1.4 29.8 5.4 48.5
II 59.0 5.3 8.9 1.4 29.7 5.1 49.6
Mean 61.6 5.2 9.4 1.4 29.8 5.3 49.1

Damaged Bermudagrass

I 51.5 5.5 7.4 1.1 30.0 4.6 51.4
II 38.5 5.2 8.1 1.1 29.3 4.6 51.7
Mean 45.0 5.4 7.8 1.1 29.7 4.6 51.5






- 59 -


less protein in the damaged bermudagrass.

Economic Importance of P. bicincta

Washbon (91) showed that infestations of spittlebugs caused serious

nutritive depletions in St. Augustinegrass. Similar results were obtained

for pangolagrass and bermudagrass in this study. Although yield data are

not available specifically for P. bicincta, observations on other sucking

pests indicated they can reduce the gross yield of pasture grasses often

in excess of 50% (26). So the result of spittlebug injury is less grass

with less nutrients.

Heavy spittlebug infestations and the resulting damage lowers the

palatability of grass (31), reduces root production and sod reserves (58),

is related to weed invasion into improved pastures (28), and may be impor-

tant in the incidence of gray leaf spot disease on pasture grasses (91).

Spittlebug damaged pangolagrass may be more susceptible to winter killing

than healthy grass.

Reports of spittlebug damage in Florida have occurred from 2 basic

problems. First, damage to pangolagrass occurs generally to tall heavy

stands during wet years. This thickly matted grass provides the optimum

habitat for spittlebugs. When pangolagrass is held in this condition for

later harvesting or for winter pasture, spittlebugs build up to the point

where damage occurs. Tall grass pastures are especially susceptible to

injury in August and September.

Secondly, newly planted St. Augustinegrass is easily damaged and killed

by adult spittlebugs. This usually occurs when the new grass is planted

in August and September. Well established mature St. Augustinegrass seems

to be very tolerant to spittlebug feeding because it takes a very high

adult population to produce injury.






- 60 -


Control

Light Traps

Cardin (11) first suggested using light traps to control P. bicincta

in 1917. In Florida up to 10,000 spittlebugs per night were captured by

a single light trap set in a heavily infested area. Even so, many adults

have been observed resting on grass around a light trap in the early morn-

ing indicating some inefficiency in trapping. Sweeping of those spittle-

bugs showed they were predominantly males.

When light traps 50 feet apart were run in a highly infested pasture,

each trap caught about the same number of spittlebugs that it would have

caught if run separately. No data were collected on the number of traps

per unit of land that would be necessary to reduce the spittlebug popula-

tion.

Since mostly males are attracted, lights might be important in the

future should a chemosterilization program ever be developed against the

two-lined spittlebug.

Cultural Control

Cultural control generally involves the use of management, harvesting,

and machinery as preventive measures which are usually employed in advance

of the time that damage may occur. Often they are the only control mea-

sures that can be employed profitably with crops of great acreage and low

unit value, such as pastures.

For cultural control to succeed, it is necessary to understand the

life history and habits of the insect in question. Practices are then

directed against some particularly weak point in the life cycle or adapta-

tion of the insect pest to its environment.

Beck (3) observed that burning Coastal bermudagrass in April gave






- 61 -


100% control of P. bicincta in Georgia. Furthermore, mowing and raking

also reduced the nymphal population. From these observations, Beck con-

cluded that the insect may be substantially controlled by good pasture

management and efficient use of the grass as forage. Hodges, et al. (31)

suggested heavy grazing or removal of spittlebug infested pangolagrass

for hay or silage as a means of controlling or reducing spittlebug damage.

During many attempts to raise spittlebugs under artificial conditions,

the eggs were easily desiccated and the nymphs killed by low moisture or

humidity conditions. Undoubtedly, under field conditions many eggs fail

to hatch and nymphs fail to survive unless they are protected from des-

iccation. Any cultural practice which would lessen or prohibit the pro-

tection provided by the heavy thick canopy of grass should reduce the

spittlebug population

Burning.--Beck (3) found that spring burning destroyed the overwintering

eggs of P. bicincta in Coastal bermudagrass at Tifton, Georgia. However,

pangolagrass apparently is injured by burning (31). Bermudagrass returns

from rhizomes after burning but pangolagrass is stoloniferous and cannot

withstand burning to the degree required for removal of all debris and

above ground vegetation.

Strayer (57) recommends burning Coastal bermudagrass pastures in

late February or early March for spittlebug control in Florida. If the

pasture contains clover, it can be burned late in the fall.

Mowing.--In an experiment where pangolagrass was cut with a rotary mower

to a height of h in., nymphs were significantly reduced (Table 10). How-

ever, the percent control was very low. Mowing may give some control of

early instars which are more susceptible to desiccation. It is employed

primarily to harvest the forage to prevent further loss of nutritive value.






- 62 -


Pastures which have not had the sod disturbed for a number of years

have a great deal of litter and debris at the soil surface which provides

added protection for spittlebug n;mphs. Under these conditions it seems

unlikely that mowing the grass to height practical under normal agronomic

practices (h-6 in.) would greatly reduce the nymphal population.

Adult spittlebugs tend to move out of short grass. Mowing'at the

times when adult populations are highest should inhibit spittlebug injury.

Grazing.--Heavy grazing to rapidly remove spittlebug infested grass is

recommended whenever animal numbers and size of area permit. Rapid re-

moval of herbage is essential as it opens the stand and allows access to

birds and promotes drying of the grass crowns. Close grazing to prevent

heavy growth of grass in midsummer is one method of controlling spittle-

bugs (31).

In August, 1968, infested pastures at the Range Cattle Station aver-

aged about 6 nymphs per square foot under grazing compared to 17 per

square foot in non-grazed areas.

In central Florida, pangolagrass probably can be grazed extremely

close during the months spittlebug damage is most common (August and

September) and still produce pasture for winter. A pasture grazed until

September 1 should return to the head stage by middle October (45 days);

if grazed until October 1, it should be in the head stage in 60 days,

thus providing some winter pasture if fertilized and deferred.

Dense bunch grasses (vaseygrass and smutgrass) may increase spittle-

bug problems even in grazed improved pastures. The high level of palata-

bility of pangolagrass often results in cattle grazing it in preference

to other vegetation, thus allowing the bunch grasses to retain the dense

habitat favorable to spittlebug eggs, nymphs, and adults.






- 63 -


Harvesting.--Harvesting spittlebug damaged grass for hay or silage pre-

vents further quality decline and usually brings spittlebug activity to a

halt (31). Removing the grass is especially efficient in controlling the

early instar nymphs. Some later instars are undoubtedly also killed but

many are able to resist desiccation and develop to adults. The adults

migrate to taller grass, then return when the lush new growth again affords

food and protection.

Harvesting in late summer should prohibit damage and still provide

winter pasture as outlined under the section on grazing. If the grass

is harvested in August, it may be profitable to not fertilize it for

about a month. The slow growing short grass is then not attractive during

the period when adult spittlebug populations are highest and overwintering

eggs would not be deposited in the field. Pastures fertilized after the

spittlebug population declines should develop for winter use.

Renovation.--Renovated pangolagrass pastures usually are not subject to

spittlebug damage for at least 2 years. The soil surface in these pastures

is void of litter and debris conducive to spittlebug development. Some

time is necessary before conditions typical of an undisturbed sod return

and spittlebugs develop high populations again in the field.

Chopping and discing.--Chopping or discing spittlebug infested pastures

destroys the eggs, disturbs the sod, and opens the stand for drying. On

August 15, 1968, a pangolagrass pasture at the Range Cattle Station which

had been chopped on July 1 averaged less than 1 nymph per square foot com-

pared to 17 per square foot in non-chopped areas.

Planting time.--Spittlebugs have caused serious damage to St. Augustinegrass

planted in August and September. Planting in the spring (April to June),

should allow St. Augustinegrass to become well established before the






- 6 -


adult spittlebug population peaks. Well established St. Augustinegrass

seems able to withstand high spittlebug infestations in June and July

without injury.

Pangolagrass is normally planted to take advantage of the rainy

months and new plantings have not been effected by spittlebugs.

Grass-legume mixtures.--Two-lined spittlebugs have not been reported on

or the adults causing injury to legumes. Mixed pastures may lessen

spittlebug damage.

Grass varieties.--Two factors appear to influence the probability of

spittlebug injury to grasses; the attractiveness of grasses to spittle-

bugs, and the tolerance of grasses to spittlebug injury. All of the

grasses in the trial except the Digitaria crosses have previously been

recorded as hosts. Thus they are assumed to be attractive and would make

good hosts should the grass be extensively planted in the future.

However, some of the grasses seem to be more tolerant than others

(Table 8). Digitaria decumbens designated USDA P. I. #111110 is widely

planted as pangolagrass in Florida and is used as a standard for comparison

in this study. Two species of Brachiaria and 2 introductions of Hemarthria

altissima showed little or no damage. Two Digitaria crosses were also

less damaged than pangolagrass.

From many field observations the major improved pasture grasses in

Florida can be ranked from the most susceptible to spittlebug injury to

the least as follows: bermudagrass, pangolagrass, St. Augustinegrass, and

bahiagrass.

The tolerance some grasses show to spittlebug feeding may be influ-

enced by environmental factors. Pangolagrass is injured in late summer

but not by the 1st generation adults in June. It is in a rapid vigorous









state of growth at that time. But by late summer, grasses on mineral

soils undergo a severe water stress. Under water stress, pangolagrass

appears to be more susceptible to injury by the 2nd generation of spittle-

bugs. In contrast, St. Augustinegrass in the Belle Glade area undergoes

water stress later and of a less severe nature because of the water hold-

ing capacity of the organic soils. This may contribute to St. Augustine-

grass' tolerance to spittlebug injury.

Chemical Control

A perusal of the literature shows that only a few insecticides have

any promise of controlling P. bicincta adults and nymphs in tall grass.

Nearly all of this information comes from experiments conducted in South

Carolina and Georgia on Coastal bermudagrass. Little chemical control

information is available for Florida.

Because of the small plots and the mobility of the adults, usable

control data were difficult to obtain. Only data taken within 3 days

after application were considered valid for the adults. Nymphs were not

sampled until at least h8 hours after application to allow time for the

spittlemasses to disintegrate if control was effected. Treatments against

the nymphs were considered ineffective if 85% control was not obtained.

1967 Experiments.--Experiment l.--Granular applications of chlordane,

dieldrin, and parathion at 3 Ib Al/acre were effective in controlling the

1 generation nymphs (Table 9). A residual insecticide applied at the

right time in the spring should control the new nymphs as they search for

a suitable feeding site. A thorough knowledge of the climatic factors

that initiate the hatching of the eggs is needed so that applications can

be timed properly.

Experiment 2.--In Table 10 plots which were mowed and treated with


- 65 -





- 66 -


Table 8.--Visual rating of damage to grasses by Prosapia bicincta in a
field trial. Ona, Florida. October 11, 1968.


USDA Mean Visual
Species P.I. No. Rating*

Brachiaria sp. 299498 1.00 ai*
B. humidicola 257678 1.00 a
Hemarthria altissima 299993 1.13 a
H. altissima 299994 1.25 a
H. altissima 299995 4.00 b
iigitaria cross F1x124-4 4.00 b
Digitaria cross F1x125-7 4.25 bc
D. pentzii 299828 4.75 bcd
Cynodon dactylon 224152 5.50 cde
Digitaria cross F1xl25-; 5.50 cde
D. pentzii 299753 6.00 def
D. valida 299810 6.00 def
5. decumbens pangolagrass 111110 6.00 def
Digitaria sp. 300935 6.00 def
D. pentzii 279651 6.50 efg
Cynodon dactylon 225957 6.50 efg
C. dactylon Coast Cross-1 7.00 efgh
Digitaria decumbens 299601 7.16 fgh
D. pentzii 299602 7.67 gh
D. gazensis 299637 8.25 h


"Rating scale % brown grass per plot
1 ( 0 20)
3 (20 0%)
5 (40 60%)
7 (60 80%)
9 (80 100)


8MYeans followed by the same letter are not significantly different at
the 5% level, (Duncan's multiple range test).





- 67 -


Table 9.-- Chemical control of the first generation nymphs of Prosapia
bicincta in pangolagrass at the Range Cattle Station, Ona,
Florida, 1967. Experiment 1.


Treatment Lb June 18
May 16, 1967 AI/acre No. nymphs/ft.2


Chlordane 10% G 3.0 0.00

Dieldrin 10% G 3.0 0.00

Parathion 10% G 3.0 0.00

Check 0.0 2.00









- 68 -


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- 69 -


carbaryl and parathion contained significantly fewer nymphs than check

plots. Even so, the percent of control was very low. This suggests that

the materials used in this experiment, which are among those cleared for

use on pastures, will not control the nymphs even in short grass.

Experiment 3.--Examination of Table 11 shows that applications of

azinphosmethyl, even at 0.5 lb AI/acre, initially controlled the adults.

After 6 days, the 1, 1.5, and 2 lb AI/acre rates showed significant control.

Data recorded 16 days after application are probably not reliable. Nymphs

were not controlled at any of the rates used in this experiment.

Experiment h.--All of the materials except Dyfonate provided signifi-

cant control of the adults at the 2 day interval (Table 12). Aldicarb,

Dursban G, Supracide, and Dursban EC gave 89%, 89%, 89%, and 86% control

of the adults respectively. Data collected at the 12 day interval were

not considered sound.

Aldicarb, carbofuran, and Bayer 37289 at 2 lb AI/acre were the best

materials used in the test against the nymphs (Table 13). The former 2

are systemic carbamates. Dursban at 0.2 lb AI/acre and Mobam at 2 lb AI/acre

also gave adequate control (above 85%).

1968 Experiments.--Experiment l.--The systemic insecticide, phorate, at 1

and 2 lb AI/acre initially gave 92% and 96% control of the adults respec-

tively (Table lh). Table 15 shows that these same rates gave excellent

control of the nymphs through 27 days after application.

No phytotoxicity was noted at any of the rates. At the higher rates,

phorate noticeably stimulated the growth of the grass beyond that which

could be attributed to insect control. In 2 weeks grass in these plots

was greener and taller than grass in the check plots.

Experiment 2.--None of the materials gave significant control of the

nymphs (Table 16). Materials in spray formulations apparently do not reach








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- 78 -


the nymphs. The addition of Triton X-100 and application of 100 gal of

water per acre did not increase the effectiveness of either parathion or

carbaryl against the nymphs. All of the treatments provided good control

of adults at the 1 day interval. Results are erratic after the first day.

Experiment 3.--Only aldicarb and Dursban demonstrated significant

control of the adults after 1 day (Table 17). No significant control was

obtained at the 11 day interval even though aldicarb showed 93% control.

Materials applied in the granular formulation may not be as effective

against the adults as they might be when applied as sprays.

Aldicarb at 0.5 lb AI/acre demonstrated excellent control against the

nymphs through 20 days (Table 18). Dyfonate at 1 lb AI/acre exhibited 87%

control after 20 days. Dursban at 0.5 lb AI/acre and carbofuran and

methomyl each at 1 lb AI/acre approached adequate control.

Experiment h.--Baygon at 1.5 Ib AI/acre and methomyl at 2 Ib AI/acre,

both having systemic properties, gave excellent control of nymphs at the

13 day interval (Table 19). Dyfonate and Bayer 37289 each at 1 lb AI/acre

also gave excellent control. Although not systemics, they have closely

related chemical structures which seem to be effective in controlling the

nymphs.

At the time of application, most of the nymphs in the field were in

the last instar. Between the 6 day and 13 day intervals there was an ex-

tensive emergence of adults in the area. This explains the reduction in

the number of spittlemasses per square foot in the check plots.

Table 20 indicates that Dyfonate, methomyl, Bayer 37289, and Baygon

were superior in their ability to protect the grasses from damage by

spittlebugs. Each had a mean rating of less than 1 which indicated that

the grasses in those plots varied from no damage to some yellowing with









- 79 -


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little browning. No phytotoxicity was noted in any of the treatments.

Experiment 5.--Aldicarb at 0.5 lb AI/acre again proved to be the best

material for controlling spittlebug nymphs (Table 21). Phorate, carbofuran,

and Dasanit each at 1 Ib AI/acre gave 97%, 97%, and 9h% control, respec-

tively, at the 13 day interval. The systemics, dimethoate and disulfoton,

were ineffective at the rates used.

As might be expected Table 22 indicates that phorate, aldicarb,

carbofuran, Dasanit, and parathion best protected the grasses against

spittlebug damage. No phytotoxicity was recorded.

Summary on chemical control.--It might be advantageous to review the habits

of the two-lined spittlebug as related to possible control measures. Adults

emerge throughout the growing season with peaks in June and September. They

probably live about 3 weeks in the field. They are rather inactive during

the hottest part of the day and tend to stay in the same habitat as the

nymphs; i.e., next to the soil with the top growth of the grass protecting

them. The adults, especially the males, tend to be much more active on

cloudy days and at night.

Although they are difficult to reach directly with a chemical during

the day, they should come in contact with a residual on the grass or soil

during their night time movements. Experiments have proven that sprayed

materials will control the adults. If possible, sprays should be applied

at the beginning of a 3-h day dry period. This will allow 2-3 nights for

the adults to come in contact with the insecticide deposited on the grass.

Granular formulations of insecticides may be as effective as sprays when

they are applied over an extensive area. The granules would fall down

through the grass and rest where the adults spend their daylight hours.

As granules, the insecticide is kept down under the grazing level of the


- 85 -







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- 89 -


livestock and should reduce the residue hazard on grass unless a systemic

is used.

Of the materials with clearance for use on pastures, carbaryl has

given the best control. This insecticide sprayed at 1.5 lb AI/acre over

a large enough area should control the adults. If the pasture is held for

a long period, it may be necessary to repeat the treatment. Any short

residual spray treatments which control the adults and not the nymphs will

provide only temporary control for new adults will be continually emerging.

Nymphs tend to wander about after hatching in search of a feeding

site. They should be susceptible to residual insecticides at the soil

surface. The nymphs feed next to the ground on runners, roots, and stems

where they are protected by their spittlemass, debris, and the canopy of

grass. Under these conditions it is difficult to reach the nymph with an

insecticide. The nymphal stage lasts about 50 days under optimum condi-

tions.

Spray treatments, even with the systemic, dimethoate, did not give

good nymphal control. A systemic sprayed on the foliage would have to be

translocated down to be effective. In contrast, granular systemics have

proved superior in controlling the nymphs. On granules the systemic is

placed near the roots where the plant absorbs and translocates it upward

past the site of the feeding nymph.

Systemics tend to even out poor distribution in application, extend

the residual effect in that deposits are not washed off as are those of

conventional sprays and dusts, and, because of their selectiveness against

sucking insects, they can control plant pests without eliminating benefi-

cial insects. Unfortunately there are no systemics presently cleared for

use on pastures.







90 -


Control measures will vary according to the circumstances. When the

infestation appears to be localized, a spot treatment may be all that is

necessary. For other infestations, a thorough application over a large

area may be needed.















ECONOMIC IMPORTANCE, CULTURAL AND
CHEMICAL CONTROL OF Prosapia plagiata
ON KIKUYUGRASS IN COSTA RICA



About 20 years ago (19h7) entomologists at the Ministerio de Agri-

cultura of Costa Rica first received reports of kikuyugrass (Pennisetum

clandestinum Hochst.) pastures turning yellow, then brown and dying.

Upon investigation, this damage was attributed to high populations of the

spittlebug, Prosapia plagiata (Distant). This species apparently injures

grass in the same manner reported for P. bicincta in the southeastern

United States. Phytotoxic salivary substances injected into the plant by

adult spittlebugs during feeding cause progressive symptoms of injury

depending upon the degree of infestation and length of feeding time. In

a typical year, damage first appears in June and by August and September

entire pastures are yellow and brown from spittlebug injury.

A review of the literature revealed only a few papers on the species,

mostly concerning the taxonomic position. Washbon (91) presented some

information on the biology, ecology and control of P. plagiata. Most of

his work was done in cooperation with this writer and Ovidio Vargas P. of

the Departmento de Entomologia, Ministerio de Agricultura y Ganaderia,

San Jose, Costa Rica.

Synonymy

Sphenorhina plagiata Distant 1878. (14)

Tomaspis plagiata Fowler 1897. (21)

Tomaspis distant Lallemand 1912. (37)


- 91 -






- 92 -


Sphenorhina biformis Lallemand 1927. (38)

Prosapia plagiata (Distant) Fennah 1953. (17)

Description

P. plagiata can be differentiated from other related forms according

to the following family, generic, and specific characters. The beak arises

from the hind part of the head. The tarsi are 3-segmented. The antennae

are very short, bristle-like, and inserted on the front of the head be-

tween the eyes. Two ocelli are present on the vertex. The hind tibia

bear two stout spines and a crown of short spines around the apex. The

anterior margin of the pronotum is straight. The third joints of the

antennae are slightly conical, with the shorter arista placed distinctly

basa of the long arista. The postclypeus is abruptly rectangulate in

profile. The pronotum is dark and transversed by a broad pale band. The

tegmina is usually a sordid yellowish brown and always devoid of markings

(Figure 12).

There are two distinct color forms of P. plagiata, a brown and a red.

The ground color of the body, abdomen, and the pronotum is very dark fus-

cous or fuscous-piceous in both. But the tegmina, transverse pronotal

band, postclypeus,and parts of the legs of the brown form are a sordid

yellowish-brown. In the red form, all parts of the insect corresponding

to the yellowish-brown color of the brown form are rufus to rosy brown.

The red form is not rare but is not nearly as prevalent as the brown

form. It has been collected occasionally in many of the localities that

the species is found but appears in highest numbers in one particular

area northeast of San Isidro de Coronado. Both sexes can be found where-

ever the red form occurs. Also many individuals showing intermediate

color shades can be found. On one occasion a red form female was observed