• TABLE OF CONTENTS
HIDE
 Front Cover
 Front Matter
 Table of Contents
 Introduction
 American grasshopper
 Biology
 Injury
 Control
 Grasshoppers of lesser economic...
 Summary
 Literature cited






Group Title: Bulletin - University of Florida Agricultural Experiment Station ; 496
Title: Grasshoppers in citrus groves
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00026528/00001
 Material Information
Title: Grasshoppers in citrus groves
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 26 p. : ill., map ; 23 cm.
Language: English
Creator: Griffiths, James T ( James Thompson ), 1914-
Thompson, W. L
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1952
 Subjects
Subject: Locusts -- Control -- Florida   ( lcsh )
Citrus -- Diseases and pests -- Florida   ( lcsh )
Citrus -- Diseases and pests -- Control -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: p. 25-26.
Statement of Responsibility: by J.T. Griffiths and W.L. Thompson.
General Note: Cover title.
General Note: "A contribution from the Citrus Experiment Station"--T.p.
Funding: This collection includes items related to Florida’s environments, ecosystems, and species. It includes the subcollections of Florida Cooperative Fish and Wildlife Research Unit project documents, the Florida Sea Grant technical series, the Florida Geological Survey series, the Howard T. Odum Center for Wetland technical reports, and other entities devoted to the study and preservation of Florida's natural resources.
 Record Information
Bibliographic ID: UF00026528
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000925761
oclc - 18266860
notis - AEN6417

Table of Contents
    Front Cover
        Page 1
    Front Matter
        Page 2
        Page 3
    Table of Contents
        Page 4
    Introduction
        Page 5
        Page 6
        Page 7
    American grasshopper
        Page 8
        Page 9
    Biology
        Page 10
        Page 11
        Page 12
    Injury
        Page 13
        Page 14
        Page 15
    Control
        Page 16
        Page 15
        Chemical control
            Page 17
            Page 18
            Page 19
    Grasshoppers of lesser economic importance
        Page 20
        Eastern Lubber Grasshopper
            Page 20
            Page 21
        Red-legged grasshopper
            Page 22
        Other minor species
            Page 22
            Page 23
    Summary
        Page 24
    Literature cited
        Page 25
        Page 26
Full Text


Ju 2 128
June 1952


Bulletin 496


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATIONS
WILLARD M. FIFIELD, Director
GAINESVILLE, FLORIDA
(A CONTRIBUTION FROM THE CITRUS EXPERIMENT STATION)





Grasshoppers in Citrus Groves

By J. T. GRIFFITHS and W. L. THOMPSON


Single copies free to Florida residents on request to
AGRICULTURAL EXPERIMENT STATION
GAINESVILLE, FLORIDA


L5









BRANCH STATIONS

NORTH FLORIDA STATION, QUINCY
W. C. Rhoades. Jr.. M.S, Entomologist
R. R. Kincaid, Ph.D., Plant Pathologist
L. G. Thompson, Jr., Ph.D., Soils Chemist
W. H. Chapman, M.S., Asso. Agronomist
Frank S. Baker. Jr., B.S., Asst. An. Husb.
T. E. Webb, B S.A., Asst. Agronomist

Mo'ile Unit, Monticello
R. W. Wallace, B.S.. Associate Agronomist
Mobile Unit. Marianna
R. W. Lipscomb, M.S., Associate Agronomist
Mobile Unit, Pensacola
R. L. Smith, M.S., Associate Agronomist
Mobile Unit, Chipley
J. B. White. B.S.A., Associate Agronomist
CITRUS STATION, LAKE ALFRED
A. F. Camp, Ph.D., Vice-Director in Charge
W. L. Thompson, B.S., Entomologist
R. F. Suit, Ph.D., Plant Pathologist
E. P. Ducharme, Ph.D., Asso. Plant Path.
C. R. Stearns, Jr., B.S.A., Asso. Chemist
J. W. Sites, Ph.D., Horticulturist
H. 0. Sterling, B.S., Asst. Horticulturist
H. J. Reitz, Ph.D., Horticulturist
Francine Fisher, M.S., Asst. Plant Path.
I. W. Wander, Ph.D., Soils Chemist
J. W. Kesterson, M.S., Asso. Chemist
R. Hendrickson, B.S., Asst. Chemist
Ivan Stewart, Ph.I., Asst. Biochemist
D. S. Prosser, Jr., B.S., Asst. Horticulturist
R. W. Olsen, B.S., Biochemist
F. W. Wenzel, Jr., Ph.D., Chemist
Alvin H. Rouse, M.S., Asso. Chemist
H. W. Ford, Ph.D., Asst. Horticulturist
L. C. Knorr, Ph.D., Asso. Histologist
R. M. Pratt, Ph.D., Asso. Ent.-Pathologist
J. W. Davis, B.S.A., Asst. in Ent.-Path.
W. A. Simanton, Ph.D., Entomologist
E. J. Deszyck, Ph.D., Asso. Horticulturist
C. D. Leonard, Ph.Y., Asso. Horticulturist
I. Stewart, M.S., Asst. Biochemist
W. T. Long, M.S., Asst. Horticulturist
M. H. Muma, Ph.D., Asst. Entomologist
F. J. Reynolds, Ph.D., Asso. Hort.
E. J. Elvin, B.S., Asst. Hort.
W. F. Spencer, Ph.D., Asst. Chem.
I. H. Holtsberg, B.S.A., Asst. Entomologist-
Pathologist
K. G. Townsend, B.S.A., Asst. Entomologist-
Pathologist
J. B. Weeks, B.S., Asst. Entomologist
E. C. Lundbert, B.S.A., Asst. Biochemist
N. F. Shimp, M.S.. Asst. Chem.
R. B. Johnson, M.S., Asst. Entomologist

EVERGLADES STATION. BELLE GLADE
R. V. Allison, Ph.D., Vice-Director in Charge
Thomas Bregger, Ph.D., Physiologist
J. W. Randolph, M.S., Agricultural Engr.
W. T. Forsee, Jr., Ph.D., Chemist
R. W. Kidder, M.S., Asso. Animal Husb.
C. C. Seale, Asso. Agronomist
N. C. Hayslip,. B.S.A., Asso. Entomologist
E. A. Wolf, M.S., Asst. Horticulturist
W. H. Thames, M.S., Asst. Entomologist
W. N. Stoner, Ph.D., Asst. Plant Path.
W. A. Hills, M.S., Asso. Horticulturist
W. G. Genung, B.S.A., Asst. Entomologist
Frank V. Stevenson, M.S., Asso. Plant Path.
Robert J. Allen, Ph.D., Asst. Agronomist
V. E. Green, Ph.D., Asst. Agronomist
J. F. Darby, Ph.D., Asst. Plant Path.
H. L. Chapman, Jr.. M.S.A., Asst. An. Husb.
Those. G. Bowery, Ph.D., Asst. Entomologist
V. L. Guzman, Ph.D., Asst. Hort.
M. R. Bedsole, M.S.A., Asst. Chem.


SUB-TROPICAL STATION, HOMESTEAD
Geo. D. Ruehle, Ph.D., Vice-Dir. in Charge
D. O. Wolfenbarger, Ph.D., Entomologist
Francis B. Lincoln, Ph.D., Horticulturist
Pobert A Conover, Ph.D., Plant Path.
John L. Malcolm, Ph.D., Asso. Soils Chemist
R. W. Harkness, Ph.D., Asst. Chemist
R. Bruce Ledin, Ph.D., Asst. Hort.
J. C. Noonan, M.S., Asst. Hort.
M. H. Gallatin, B.S., Soil Conservationist

WEST CENTRAL FLORIDA STATION,
BROOKSVILLE
William Jackson, B.S.A.. Animal Husband-
man in Charge 2

RANGE CATTLE STATION, ONA
W. G. Kirk, Ph.D., Vice-Director in Charge
E. M. Hodges, Ph.D., Agronomist
D. W. Jones, M.S., Asst. Soil Technologist

CENTRAL FLORIDA-STATION, SANFOBD
R. W. Ruprecht, Ph.D., Vice-Dir. in Charge
J. W. Wilson, Sc.D., Entomologist
P. J. Westgate, Ph.D., Asso. Hort.
Ben. F. Whitner, Jr., B.S.A., Asst. Hort.
Geo. Swank, Jr., Ph.D., Asst. Plant Path.

WEST FLORIDA STATION, JAY
C. E. Hutton, Ph.D., Vice-Director in Charge
H. W. Lundy, B.S.A., Associate Agronomist
W. R. Langford, Ph.D., Asst. Agron.

SUWANNEE VALLEY STATION,
LIVE OAK
G. E. Ritchey, M.S., Agronomist in Charge

GULF COAST STATION, BRADENTON
E. L. Spencer, Ph.D., Soils Chemist in Charge
E. G. Kelsheimer, Ph.D., Entomologist
David G. A. Kelbert, Asso. Horticulturist
Robert O. Magie, Ph.D., Plant Pathologist
J. M. Walter, Ph.D., Plant Pathologist
DonalM S. Burgis, M.S.A., Asst. Hort.
C. M. Geraldson, Ph.D., Asst. Hort.
W. G. Cowperthwaite, Ph.D., Asst. Hort.
Amegda Jack, M.S., Asst. Soils Chemist

FIELD LABORATORIES
Watermelon, Grape, Pasture-Leesburg
C. C. Helms, Jr., B.S., Asst. Agronomist*
L. H. Stover, Asst. In Hort.

Strawberry-Plant City
A. N. Brooks,, Ph.D., Plant Pathologist
Vegetables-Hastings
A. H. Eddins, Ph.D., Plant Path. in Charge
E. N. McCubbin, Ph.D., Horticulturist
T. M. Dobrovsky, Ph.D., Asst. Entomologist
Pecans-Monticello
A. M. Phillips, B.S., Asso. Entomologist'
John R. Large, M.S., Asso. Plant Path.
Frost Forecasting-Lakeland
Warren .O. Johnson, B.S., Meteorologist

1 Head of Department
2 In cooperation with U. S.
3 Cooperative, other divisions, U. of F.
'On leave.









BOARD OF CONTROL
Frank M. Harris, Chairman, St. Petersburg
Hollis Rinehart, Miami
Eli H. Fink, Jacksonville
George J. White, Sr., Mount Dora
Mrs. Alfred I. duPont, Jacksonville
George W. English, Jr., Ft. Lauderdale
W. Glenn Miller, Monticello
W. F. Powers, Secretary, Tallahassee
EXECUTIVE STAFF
J. Hillis Miller, Ph.D., President
J. Wayne Reitz, Ph.D., Provost for Agr.'
Willard M. Fifield, M.S., Director
J. R. Beckenbach, Ph.D., Asso. Director
L. O. Gratz, Ph.D., Asst. Dir.,
Rogers L. Bartley, B.S., Admin. Mgr.3
Geo. R. Freeman, B.S., Farm Superintendent

MAIN STATION, GAINESVILLE

AGRICULTURAL ECONOMICS
H. G. Hamilton, Ph.D., Agr. Economist 1
R. E. L. Greene, Ph.D., Agr. Economist
M. A. Brooker, Ph.D., Agr. Economist 3
Zach Savage. M.S.A., Associate
A. H. Spurlock, M.S.A., Associate
D. E. Alleger, M.S., Associate
V. L. Brooke, M.S.A., Associate'
M. R. Godwin, Ph.D., Associate 3
Tallmadge Bergen, B.S., Assistant
W. K. McPherson, M.S., Economist
Erie Thor, M.S., Agr. Economist
J. L. Tennant, Ph.D., Agr. Economist
Orlando, Florida (Cooperative USDA)
G. Norman Rose, B.S., Asso. Agr. Economist
J. C. Townsend, Jr., B.S.A., Agr.
Statistician 2
J. B. Owens, B.S.A., Agr. Statistician s
J. K. Lankford, B.S., Agr. Statistician

AGRICULTURAL ENGINEERING
Frazier Rogers, M.S.A., Agr. Engineer''
J. M. Johnson, B.S.A.E., Agr. Eng.S
J. M. Myers, B.S., Asso. Agr. Engineer
J. S. Norton, M.S., Asst. Agr. Eng.

AGRONOMY
Fred H. Hull, Ph.D., Agronomist1 2
G. B. Killinger, Ph.D., Agronomist
H. C. Harris, Ph.D., Agronomist
R. W. Bledsoe, Ph.D., Agronomist
W. A. Carver, Ph.D., Associate
Darrel D. Morey, Ph.D., Associate 2
Fred A. Clark, M.S.A., Assistant2
Myron C. Grennell, B.S.A.E., Assistant
E. S. Horner, Ph.D., Assistant
A. T. Wallace, Ph.D., Assistants
D. E. McCloud, Ph.D., Assistant 3
H. E. Buckley, B.S.A., Assistant
E. C. Nutter, Ph.D., Asst. Agronomist
ANIMAL HUSBANDRY AND NUTRITION
T. J. Cunha, Ph.D., An. Husb.1
G. K. Davis, Ph.D., Animal Nutritionists
S. John Folks, Jr., M.S., Asst. An. Husb.
Katherine Boney, B.S., Asst. Chem.
A. M. Pearson, Ph.D., Asso. An. Husb.3
John P. Feaster, Ph.D., Asst. An. Nutri.
H. D. Wallace, Ph.D., Asst. An. Husb.3
M. Koger, Ph.D., An. Husbandmans
G. E. Combs, Jr., B.S.A., Asst. Animal
Husbandman
E. F. Johnston, M.S., Asst. Animal Husband-
man
DAIRY SCIENCE
E. L. Fouts, Ph.D., Dairy Tech.'s
R. B. Becker, Ph.D., Dairy Husb.3
S. P. Marshall, Ph.D., Asso. Dairy Husb.3
W. A. Krienke, M.S., Asso. Dairy Tech. I


P. T. Dix Arnold, M.S.A., Asst. Dairy Husb.'
Leon Mull, Ph.D., Asso. Dairy Tech.
H. H. Wilkowske, Ph.D., Asst. Dairy Tech.
James tl. Wing, M.S., Asst. Dairy Hush.
EDITORIAL
J. Francis Cooper, M.S.A., Editor"
Clyde Beale, A.B.J., Associate Editor'
L. Odell Griffith, B.A.J., Asst. Editor'
J. N. Joiner, B.S.A., Assistant Editor s

ENTOMOLOGY
A. N. Tissot, Ph.D., Entomologist'
L. C. Kuitert, Ph.D., Associate
H. E. Bratley, M.S.A., Assistant
F. A. Robinson, M.S., Asst. Apiculturist
R. E. Waites, Ph.D., Asst. Entomologist

HOME ECONOMICS
Ouida D. Abbott, Ph.D., Home Econ.'
R. B. French, Ph.D., Biochemist
HORTICULTURE
G. H. Blackmon, M.S.A., Horticulturist'
F. S. Jamison, Ph.D., Horticulturist
Albert P. Lorz, Ph.D., Horticulturist
R. K. Showalter, M.S., Asso. Hort.
R. A. Dennison, Ph.D., Asso. Hort.
R. H. Sharpe, M.S., Asso. Horticulturist
V. F. Nettles, Ph.D., Asso. Horticulturist
F. S. Lagasse, Ph.D., Asso. Hort.2
R. D. Dickey, M.S.A., Asso. Hort.
L. H. Halsey, M.S.A., Asst. Hort.
C. B. Hall, Ph.D., Asst., Horticulturist
Austin Griffiths, Jr., B.S., Asst. Hort.
S. E. McFadden, Jr., Ph.D., Asst. Hort.
C. H. VanMiddelem, Ph.D., Asst. Biochemist
Buford Thompson, M.S.A., Asst. Short.
LIBRARY
Ida Keeling Cresap, Librarian

PLANT PATHOLOGY
W. B. Tisdale, Ph.D., Plant Pathologist'
Phares Decker, Ph.D., Plant Pathologist
Erdman West, M.S., Mycologist and Botanist
Robert W. Earhart, Ph.D., Plant Path.'
Howard N. Miller, Ph.D., Asso. Plant Path.
Lillian E. Arnold, M.S., Asst. Botanist
C. W. Anderson, Ph.D., Asst. Plant Path.
POULTRY HUSBANDRY
N. R. Mehrhof, M.Agr., Poultry Husb.1
J. C. Driggers, Ph.D., Asso. Poultry Hush.
SOILS
F. B. Smith, Ph.D., Microbiologist 1
Gaylord M. Volk, Ph.D., Soils Chemist
J. R. Henderson, M.S.A., Soil Technologist'
J. R. Neller, Ph.D., Soils Chemist
Nathan Gammon, Jr., Ph.D., Soils Chemist
Ralph G. Leighty, B.S., Asst. Soil Surveyor'
G. D. Thornton, Ph.D., Asso. Microbiologist
Charles F. Eno, Ph.D., Asst. Soils Micro-
biologist *
H. W. Winsor, B.S.A., Assistant Chemist
R. E. Caldwe'l, M.S.A., Asst. Chemist3'
V. W. Carlisle, B.S., Asst. Soil Su veyor
James H. Walker, M.S.A., Ass Soil
Surveyor
S. N. Edson, M.S., Asst. Soil Surveyor
William K. Robertson, Ph.D., Asst. Chemist
0. E. Cruz, B.S.A., Asst. Soil Surveyor
W. G. Blue, Ph.D., Asst. Biochemist
J. G. Fiskel, Ph.D., Asst. Biochemist
H. F. Ross, B.S., Soils Microbiologist
L. C. Hammond, Ph.D., Asst. Soil Physicist
VETERINARY SCIENCE
D. A. Sanders, D.V.M., Veterinarian'
M. W. Emmel, D.V.M., Veterinarian'
C. F. Simpson, D.V.M., Asso. Veterinarian
L. E. Swanson, D.V.M., Parasitologist
Glenn Van Ness, D.V.M., Asso. Poultry
Pathologist
W. R. Dennis, D.V.M., Asst. Parasitologist

















CONTENTS
Page


INTRODUCTION -.......-- --....------- ------ ------------------- ----- -------- 5

AMERICAN GRASSHOPPER ................. .... .............................------------------ 8
BMEIoloGy--------- ------------------ _--- -------------_-------------------------.....8
Biology ... .............................. ......--....... ..--- -- -----........---- 10

Injury ..................... ............................---------......... 13

Control ....... .....---------........------ .. .. .... ................... 15

Cultural Control .................... .. ....-----....... ........ 15

Chemical Control .............----........ .......... ........ 17

GRASSHOPPERS OF LESSER ECONOMIC IMPORTANCE .....................--...------- 20

Eastern Lubber Grasshopper .................................... 20

Red-legged Grasshopper ...............-......------ ................ 22

Other Minor Species ....... .....-.... ..............--- ------...... 22

SUMMARY .................. .......... .. ................................ 24

LITERATURE CITED ...... ....... ..... ....... .............. .............. 25









Grasshoppers in Citrus Groves

By J. T. GRIFFITHS1 and W. L. THOMPSON

During the past half century grasshoppers of various species
have been recorded as periodic marauders of citrus groves in
Florida. There has seldom been severe damage over a wide area,
but in local instances control measures have been necessary to
prevent the partial or complete defoliation of citrus groves.


Fig. 1.-Orange with blemish caused by chewing of grasshopper. This
type of injury is more often caused by katydids.
1Formerly Associate Entomologist, Citrus Experiment Station, Lake
Alfred.







Florida Agricultural Experiment Stations


In addition to causing defoliation, grasshoppers will occasionally
chew holes in the peel of young fruits. This injury is similar
to that caused by katydids. Some of the fruit will drop but
others will reach maturity with unsightly blemishes (Fig. 1).
In the discussion which follows special emphasis has been
-.placed upon the
biology and con-
rol of the Ameri-
can grasshopper,
but grasshoppers
of lesser import-
ance are also
mentioned. Al-
though informi-
tion concerning
Iifll '! most of these
latter species is
incomplete in
some respects,
their known life
history, potential
economic import-
ance and control
are outlined.
Grasshoppers
are classified
among those in-
S \\\\\\\\ sects which un-
\ dergo only grad-
ual change during
Fig. 2.-Eastern lubber adults, male above, their life cycle.
female below. Note the pointed posterior tip of the
abdomen on the female. This is formed by the four Thus, even as the
blades of the ovipositors. The posterior tip on the young nymphs
male is rounded on the bottom and tends to be flat
on top. These are characteristic of the sexes of hatch from the
all species, egg they are simi-
lar in appearance to the adults. A young hopper may be readily
recognized as a grasshopper, although the species may be un-
known.
All grasshoppers have similar life histories (9).2 The female
almost always deposits her eggs in the soil. She accomplishes

SItalic figures in parentheses refer to "Literature Cited" at end of this
bulletin.







Grasshoppers in Citrus Groves


this by digging with an ovipositor-a pointed structure at the
tip end of the body (Fig. 2). By means of this she is able to
push her entire abdomen into the ground, and the eggs are thus
deposited well below the surface of the soil. Usually, several
eggs are glued together to form a pod and in some species more
than 100 eggs will make up a single egg pod. After the last egg
is laid the female secretes additional frothy material which fills
in the space between the top of the egg pod and the surface of
the soil. The plug of "froth" may be an inch in length.
In many species the winter is passed in the egg stage. Before
such eggs will hatch it is usually necessary that they be sub-
jected to low temperatures for a prolonged period. This phe-
nomenon is called the diapause. It prevents the hatching of
the eggs which are exposed to warm fall temperatures. For
those species which overwinter as nymphs or adults the eggs
usually hatch after a relatively short incubation period.
After hatching, the little grasshopers are called nymphs.
They look much like the adults but have no wings. They usually
molt five times before attaining adulthood, thus passing through
five nymphal stages or instars. The stage prior to the first
molt is the first instar, the one between the first and second
molts is the second instar, etc. Just after molting the nymph
appears as a short, stubby individual. This is caused by a tele-
scoping effect of the segments in the abdomen (Fig. 3). As
the hopper grows the membranous areas between the segments
expand and the abdomen actually elongates during the period
between molts. Just before molting the abdomen is long and
slender and the appearance of the hopper then is distinctly
different from what it is at the beginning of the instar.









\'\~'l \v
Fig. 3.-The nymph on the right is almost ready to molt from first to
second instar. Note the elongate abdomen. The individual at the left has
just completed its first molt. Note the shortened abdomen. Before the
molt the hopper is long and slender, after the molt it has a chunky
appearance.







Florida Agricultural Experiment Stations


The rudiments of small wing pads usually can be seen in the
third instar. The rudiments of the genitalia are present by
the fourth instar in many species, and the sexes can then be
differentiated.
In the adult stage the grasshopper usually has wings and is
able to fly. However, some species are totally wingless and
others with poorly developed wings are incapable of flight.
Grass hoppers often attain sexual maturity within a few weeks
after reaching adulthood. The males usually mature first and
the females normally do not lay eggs until after copulation has
taken place. In those species which pass the winter as adults
several months may intervene between the last molt and sexual
maturity.
Males may be readily differentiated from females on the basis
of the external genitalia. In the male the posterior tip of the
abdomen is rounded on the bottom and flat on the top. The
female abdomen is pointed and the tip is formed of four ovi-
positors (Fig. 2).
AMERICAN GRASSHOPPER
The American grasshopper, Schistocerca americana americana
(Drury),3 is widely distributed throughout much of North
America. It was first described by Drury in 1773. Its presence
has been recorded in the Bahamas and Mexico, as well as in
most of the United States (1, 10). In general, its range in
North America is confined to an area east of the great plains and
south of latitude 40 degrees. It is one of the most common
grasshoppers in Florida where, because of its flight character-
istics, it is referred to as the bird grasshopper (Fig. 4).








S!! ii, ,t ,t- I t '

Fig. 4.-Adult (female left, male right) of the American or bird grass-
hopper, Schistocerca americana americana.
3Usually listed as Schistocerca americana (Drury), the grasshopper
found in Florida is a sub-species, according to Dr. Irving J. Cantrall of
the University of Michigan, an authority on the orthoptera, in a letter to
the senior author.






Grasshoppers in Citrus Groves


In Florida the flying form, or adult, is particularly common
during fall. During the fall of 1946 numerous reports con-
cerned with flying grasshoppers in parts of Polk and Hardee
counties were received at the Citrus Experiment Station. Con-
trol measures were required in some areas and the grasshopper
was definitely more common than in previous years. In the
spring of 1947 severe infestations developed throughout a large
area in eastern Hillsborough County, southern and western
Polk County and northern Hardee County. Nymphs were pres-
ent in extremely large numbers and considerable damage to
citrus resulted.
In February of 1948 it was apparent from an adult survey
that infestations would be heavier than in the preceding year
(Fig. 5). However, the use of control methods reduced the




t6_' --






-- -
.. L t-...L t









*-' ~ Ii i rW w L .-
I i ..
MH
G [ .,,SS .OPkER S 5U .41 --LL--OuG".I -- -t n.
AND ARLEEC g.T5 raduul" .948 su re-iy





Fig. 5.-1948 adult grasshopper survey.







Florida Agricultural Experiment Stations


damage caused by the first generation. Exceptionally heavy
rains were experienced during July and, although it was not
demonstrated that excessive rainfall was the cause, the eggs
laid by adults of the spring or first generation failed to hatch
in July as is normal. Since that time the bird grasshopper has
not occurred in large numbers in the citrus area. No satis-
factory reasons for the reduction in numbers of that grass-
hopper in 1948 nor for the outbreak which started in 1946 have
been forthcoming. Perhaps when more information is avail-
able a practical reason for these occurrences may be known.

BIOLOGY
Under conditions in the Florida citrus belt the American
grasshopper passes through two generations per year. The
second generation overwinters in the adult stage and these
individuals are generally found in wooded areas or in open fields
where cover crop and brush are particularly dense. They tend
to seek these areas during late fall and to remain there until
warm weather in the spring. Females collected in the fall do
not have developed ovaries, nor does copulation occur in the
field at that time.
By February the adults usually leave their overwintering
habitats. They seek areas which have been cultivated during
the preceding year, but where cover crops are present. These
may be citrus groves or vegetable lands which are lying idle
at that particular time. It is in this type of habitat that ovi-
position occurs. Observations in Central Florida have indicated
that there is little tendency for eggs to be laid in grass lands
which have been maintained in sod for several years. Thus,
oviposition appears to be associated with fields which have been
under cultivation during the preceding year.
In citrus groves newly hatched grasshoppers are associated
with grassy cover crops. This is particularly true of Bermuda
sod, since it is difficult to destroy this sod by disking as normally
practiced in citrus groves. All of the grove may be clean-
cultivated except for small patches of Bermuda grass, and it
is here that the eggs are most commonly laid. Bermuda grass
serves as an attractant because it is the only grass cover in
the grove. However, Bermuda sod in pastures does not seem to
be a satisfactory place to deposit eggs. It is probable that any
cover crop in a partially or formerly cultivated field would be
attractive for an oviposition area, but since Bermuda is almost








Grasshoppers in Citrus Groves


the only one to withstand severe disking, it is the cover crop
most often associated with oviposition and subsequent hatching
in citrus groves.
During the spring of 1948 and again in 1949 surveys for adult
grasshoppers were made throughout the infested areas of Hills-
borough, Polk and Hardee counties by the Florida State Plant
Board.4 The Plant Board inspectors did not estimate the num-
ber of grasshoppers per square yard, but their procedure was to
walk approximately 75 feet into a field or grove and actually
count the number of grasshoppers which flew up. Infestations
were recorded as very light (0- 5 grasshoppers), light (5- 30),
medium (30+) and heavy (too many to count). In practice

TABLE 1.-HABITATS INFESTED WITH ADULT Schistocerca americana
americana IN FEBRUARY 1948 AND 1949.


Type of Location
Checked


I I
No. Percent of Locations Ac- Total
Locations cording to Degree of Percent
Checked I Infestation Infested


I Light* Medium Heavy
Clean
cultivated 31 16 6 10 32
Open field Formerly
cultivated 470 29 14 7 50
Never
cultivated 92 32 12 0 44

Clean
cultivated 11 0 0 0 0
Young Some cover
grove crop ....... 18 11 0 0 11
Heavy cover
crop ....... 6 0 0 17 17

Clean
cultivated 87 7 3 0 10
Old grove Some cover
crop ........ 233 24 6 3 33
Heavy cover
crop ........ 34 29 18 12 59

Wire grass
only ........ 27 26 7 0 33
Pine wood Wire grass-
other
cover crop 458 21 5 3 29

Includes those locations classified as "very light" and "light."

The late H. S. McClanahan and George Burden of the Florida State
Plant Board directed the surveys.







Florida Agricultural Experiment Stations


this method worked out relatively well and satisfactory informa-
tion concerning the extent of adult populations during February
of these two years was obtained. The survey map for 1948 is
shown in Fig. 5. One examination was made in each section
throughout the infested area. The heavy areas found in the
survey coincided very closely with those areas where subsequent
grasshopper damage to citrus was found.
The surveys were made in such a manner that infestations
were recorded in open fields, in both young and old citrus groves,
and also in pinewoods. Table 1 shows the degree of infestation
found in various habitats in the two surveys. In open fields
it will be noted that the severe infestations occurred more com-
monly in clean cultivated or formerly cultivated fields than in
those never cultivated. These data were collected at a time
when the adult grasshoppers were just beginning to emerge
from their overwintering habitat. Although a fair number of
grasshoppers were found in the uncultivated sections in Feb-
ruary, later in the year many migrate from these areas.
In both young and old groves it will be noted that a heavy
cover crop is correlated with larger numbers of grasshoppers-
the better the cover crop the higher the rate of infestation.
The data for pine woods indicated that moderate numbers of
grasshoppers were present. This again was typical of the time
of year when the survey was made. During the summer months
grasshoppers would be a rarity in a wooded section. During the
winter, however, their numbers would be quite high, and this
is reflected in the fact that infestations in pine woods were com-
mon during the surveys made in February. These data are
definitely in line with general observations throughout the period
of several years when grasshoppers were present. They clearly
indicate, as noted by Watson and Berger (13), that habitat is
of extreme importance as regards the number of grasshoppers
present in any given locality.
The time of oviposition varies with the spring temperature.
Females will often be found with well-developed ovaries as
early as February, and copulation may be noted in a field during
that month. In 1948, when there was an early spring, oviposi-
tion was first noted on February 20. At that same time nearly
50 percent of the females examined had nearly mature ovaries.
Collections of egg pods indicated that the average number of
eggs in a pod was somewhere between 75 and 80. Since the
female is a large individual she is able to deposit these eggs







Grasshoppers in Citrus Grot'es


at some depth in the soil and the top of the egg pod may be as
much as an inch below the surface.
In 1948 most of the oviposition occurred during March. Hatch-
ing was common during the first week in April, and by April 7
some second instar nymphs (Fig. 6) were observed in the field.
On April 17 the first third instar nymph was noted and on April
26 one fourth instar was found, but most of the individuals
were still in first and second instar. On May 15 some fifth
instar nymphs were present and on May 18 the first newly
emerged adult was noted in the field. Copulation among this
newly emerged generation was first noted on June 14, but it
was not until early August that a hatching of second generation
hoppers was observed. The second generation reached adult-
hood by the first week in October, and it was these adults which
remained as overwintering individuals. Observations in 1949
and 1950 substantiated the life cycle as noted here. Dates will
vary from year to year but, in general, there will be a spring
generation and a second hatch during the latter part of the
summer.








Fig. 6.-Nymphs of the American or bird grasshopper. Left to right:
second, fourth and fifth (or last) instar nymphs.

As grasshoppers reach and pass sexual maturity they take on
a yellowish cast. This is not observed in the fall, but does occur
in the spring following oviposition. Males usually change color
before the females. This coloration is a good criterion of the
fact that the grasshoppers are in the process of laying eggs
and near the end of their life span. It may be observed toward
the end of both the spring and overwintering generations.

INJURY
In general, maximum damage is done by hoppers when they
are in third, fourth and fifth instars, and it is not until they
reach third instar that the grasshoppers tend to migrate to citrus
trees. Citrus foliage does not appear to be a preferred food
but they will eat it. Laboratory results would indicate that they







Florida Agricultural Experiment Stations


Fig. 7.-Young citrus tree completely defoliated in the spring of 1948
by third, fourth and fifth instar nymphs of the American or bird grass-
hopper. A five-acre block defoliated in this manner subsequently grew
new foliage. However, almost all terminal twigs were killed.







Grasshoppers in Citrus Groves


grow poorly where citrus is the only source of food. However,
nearly full grown nymphs will feed on citrus foliage, and in
some cases complete defoliation of young trees has resulted.
In one five-acre block of four-year-old trees, complete defoliation
of the entire block by fourth and fifth instar nymphs was ob-
served in the spring of 1948 (Fig. 7). This is an exceptional
instance, but is indicative of the fact that grasshoppers can be
extremely destructive.
The adults and larger nymphs roost on the trees at night and
seem to do the bulk of their feeding on citrus foliage during
the middle and late part of the morning. During the heat of
the afternoon there appears to be very little feeding.
Once the adult stage has been reached the grasshoppers appear
to feed very little upon citrus. In fact, at that time thorough
cultivation of a grove will cause almost all of the flying forms
to leave and seek another place for feeding. Therefore, once
grasshoppers have reached adulthood control measures in citrus
groves are usually unnecessary, since very little damage is done
by adults.
CONTROL
Cultural Control.-Cover crop management is of extreme im-
portance in the control of the American grasshopper. Judicious
cultivation alone can often result in satisfactory control in an
individual grove. However, the injudicious use of chopping or
disking equipment may result in excessive damage by the
grasshoppers.
Clean cultivation acts as a deterrent to oviposition. American
grasshoppers prefer to deposit eggs in soils where grass cover
crop has grown up following cultivation and they avoid freshly
cultivated soil free from grass. Thus, in groves where grass-
hoppers are expected in the spring, it is essential that clean
cultivation be started prior to March 1.
Clean cultivation also reduces the number of nymphs which
survive after hatching. The tiny first instar hoppers must find
food and shade within a relatively short distance from the hatch-
.ing point. If no cover crop is present they will perish either
from starvation or from excessive heat.
Groves where American grasshoppers are expected during
the spring should be maintained free of cover crop from Feb-
ruary through the middle of May. This period will span the time
of oviposition, hatching and growth of the young hoppers.







Florida Agricultural Experiment Stations


Where this practice has been rigidly followed grasshopper in-
festations have been materially reduced.
Good grove management demands that cover crops be allowed
to grow in the summer in order to add organic material to the soil.
Therefore, it is essential that cover crops be allowed to grow
after the middle of May. When adult populations are present
during the summer cover crops may be thoroughly disked and
destroyed during the latter part of August. 'If a chopper is not
used in June or July this program of cover crop management
will ordinarily permit the cover crop to produce enough seed for
subsequent cropping.
In many instances growers have objected to this program on
the grounds that disking in August would adversely affect fruit
quality. Observations by horticulturists at the Citrus Station
have not substantiated this, and it is felt that cultivation can be
accomplished in August with no adverse effect on fruit maturity.
Experimentally, cultivation during that period has resulted in
grasshopper control. Clean cultivation should be continued as
long as eggs are hatching. This will usually be until some time
in September or possibly in October.
If the grasshoppers are less than one-half inch long thorough
disking will actually destroy the bulk of the nymphs present
(Table 2). However, if the young hoppers are larger than that,
disking will have little, if any, effect as a control measure. It
will simply destroy the cover crop upon which they are feeding
and, since they cannot fly, it will force them to feed on the ad-
jacent trees. Thus, if hatching is already under way before
disking is accomplished, the size of the hoppers will determine
if disking would be beneficial.

TABLE 2.-NUMBERS OF GRASSHOPPERS FOLLOWING DISKING AND CHOPPING
IN 10 GROVES IN 1947.

Date 3 Year-Old Trees 10 Year-Old Trees
__Chopped I Disked Choppedl Disked
Three days after treatment
(Colonies per 625 sq. ft.)* 8/22 7.4 7.6 6.9 2.1
Three days after second
treatment (Colonies per
625 sq. ft.)* ...................... 8/28 4.6 0.3 8.6 0.1
Nymphs per 100 sweeps .... 9/15 60 4 240 11

A colony represented the progeny from one egg pod. These stayed together for about
a week after hatching.







Grasshoppers in Citrus Groves


grow poorly where citrus is the only source of food. However,
nearly full grown nymphs will feed on citrus foliage, and in
some cases complete defoliation of young trees has resulted.
In one five-acre block of four-year-old trees, complete defoliation
of the entire block by fourth and fifth instar nymphs was ob-
served in the spring of 1948 (Fig. 7). This is an exceptional
instance, but is indicative of the fact that grasshoppers can be
extremely destructive.
The adults and larger nymphs roost on the trees at night and
seem to do the bulk of their feeding on citrus foliage during
the middle and late part of the morning. During the heat of
the afternoon there appears to be very little feeding.
Once the adult stage has been reached the grasshoppers appear
to feed very little upon citrus. In fact, at that time thorough
cultivation of a grove will cause almost all of the flying forms
to leave and seek another place for feeding. Therefore, once
grasshoppers have reached adulthood control measures in citrus
groves are usually unnecessary, since very little damage is done
by adults.
CONTROL
Cultural Control.-Cover crop management is of extreme im-
portance in the control of the American grasshopper. Judicious
cultivation alone can often result in satisfactory control in an
individual grove. However, the injudicious use of chopping or
disking equipment may result in excessive damage by the
grasshoppers.
Clean cultivation acts as a deterrent to oviposition. American
grasshoppers prefer to deposit eggs in soils where grass cover
crop has grown up following cultivation and they avoid freshly
cultivated soil free from grass. Thus, in groves where grass-
hoppers are expected in the spring, it is essential that clean
cultivation be started prior to March 1.
Clean cultivation also reduces the number of nymphs which
survive after hatching. The tiny first instar hoppers must find
food and shade within a relatively short distance from the hatch-
.ing point. If no cover crop is present they will perish either
from starvation or from excessive heat.
Groves where American grasshoppers are expected during
the spring should be maintained free of cover crop from Feb-
ruary through the middle of May. This period will span the time
of oviposition, hatching and growth of the young hoppers.







Grasshoppers in Citrus Groves


If it is found that the majority of grasshoppers are adults,
a thorough disking will generally cause these grasshoppers to
fly from the citrus grove. This phenomenon has been demon-
strated in the field on numerous occasions. Actually adult grass-
hoppers do very little damage in the citrus grove, but since they
serve as a reservoir for future generations it is desirable to force
them from the grove.
The use of cover crop choppers should be avoided when grass-
hoppers are present and insecticidal control is not planned.
Chopping does not reduce the grasshopper infestation, but it can
serve as a means of driving the hoppers from the cover crop to
the trees. Chopping reduces the amount of available food and
then the hoppers migrate to the trees.
Effects of cultivation may be summarized as follows: Clean
cultivation from February to May 15 reduces both oviposition
and the subsequent survival of the first generation nymphs.
Clean cultivation after about August 15 tends to prevent the
survival of second generation nymphs. Thorough disking will
kill most nymphs which are less than 1/ inch long, but larger
nymphs will not be killed and will be forced to feed upon the
citrus trees. Chopping destroys few nymphs and only serves to
drive the hoppers from the cover crop to the trees. However,
if only adults are present in a grove, thorough disking will
usually force them out of the clean-cultivated grove to other
places where cover crop is present.
Chemical Control.-Bird grasshoppers can be satisfactorily
controlled with several insecticides. In 1947-48 (4) it was found
that chlordane, toxaphene, parathion and benzene hexachloride
were all satisfactory materials. The bird grasshopper is ex-
tremely large and requires higher dosages of insecticide per
acre than are necessary for the control of grasshoppers in central
United States. All recommendations for the control of grass-
hoppers in Florida are based on the premise that a given amount
of toxicant is necessary per acre. The recommendations remain
the same whether the grove is a large one composed of mature
trees or a young one with small trees and considerable cover
crop. In any case, the materials should be applied uniformly
to both trees and cover crop. These insecticides act as both
stomach poisons and contact poisons and it is essential that
there be a uniform coverage of all green vegetation in the grove.
Insecticides may be applied either by duster or with a boom
or air blast type sprayer (4, 6, 7). It has been found that sprays







Florida Agricultural Experiment Stations


applied with hand machines often have been unsatisfactory be-
cause uniform coverage of the cover crop and trees was not
obtained. A mechanical spray application seems to do the best
job, and dusting is preferable to hand spraying. Table 3 shows
the amount of toxicant to be used per acre for the control of
the Florida bird grasshopper. Recommendations for the use of
aldrin on citrus are tentative, but are included in order to sug-
gest a basis for its use.
TABLE 3.-RECOMMENDED DOSAGES OF CHEMICALS FOR CONTROL OF THE
AMERICAN GRASSHOPPER, Schistocerca americana americana.

Spray Dusts
Insecticide Lbs. Toxicant % Toxicant Lbs. per
per Acre in Dust Acre

Chlordane ............................... 1.5 2.5 5 30 50
Toxaphene .............................. 3.0 4.0 10 30 40
Benzene hexachloride ............ 0.4 0.5 1 40 50
(gamma isomer)
Lindane ........................ .......... 0.4 0.5 1 40- 50
(high gamma BHC)
Parathion ..................... ........ 0.4 0.5 1 40 50
Aldrin ........ ............... ............ 0.2-0.3 21/2 10-15


Young hoppers are easiest to control. Thus, if the bulk of
the population is less than half grown less insecticide is required
than for the control of adults and large nymphs. Minimal
amounts may be applied to control infestations of young hoppers..
However, adults are difficult to control and maximum amounts
of insecticide must be used and thorough coverage obtained.
A new insecticide, aldrin, has been. recommended in other
states (12), but because grasshopper infestations have been
light this material has not been sufficiently tested on citrus in
Florida. In small scale tests it has been tried and appears to
be satisfactory. It has been recommended on idle land in Alachua
County by the Florida Experiment Station and the Florida State
Plant Board at 10 pounds per acre of a 21/ percent dust.5 It is
tentatively recommended in this bulletin, since work from other
sections of the United States (8, 12, 14) indicate that it is prob-
ably the best material so far available for grasshopper control.

6 Recommended in mimeographed circular for Alachua County Agent's
office in 1951.







Grasshoppers in Citrus Groves


Crude benzene hexachloride is recommended as well as lindane
(97% 98% gamma isomer of benzene hexachloride), but the
former should not be used when fruit is on the tree. Crude
benzene hexachloride will impart an off-flavor to oranges (5)
and, while it is a relatively cheap material, it should be used
only when fruit is not present on the trees.
Benzene hexachloride, lindane, parathion, chlordane and toxa-
phene have been found to be compatible with DN, zinc-sulfate
plus lime, neutral copper and wettable sulfur (6, 11). Com-
patibility tests for aldrin have not been made. Under no cir-
cumstances should any of these materials be used with lime-sulfur
or with other basic sprays. If it is decided to use them in com-
bination sprays containing the sulfates of zinc, manganese or
copper, a minimum amount of lime should be used (Table 4).
Chlordane and toxaphene have longer residual toxicity than
parathion or benzene hexachloride (3), although their initial
knockdown capacity is less.

TABLE 4.-MINIMUM AMOUNTS OF LIME REQUIRED TO NEUTRALIZE ZN, MN,
AND CU SULFATE.

Sulfate Lbs. of Sulfate Lbs. of Lime
Iper 100 Gals. per 100 Gals.
Copper ....... ................................ 3 1.2
Zinc .................................................. 3 1.0
Manganese .............. ................. 3 0.1


Groves should always be prepared for dusting or spraying
by first chopping or disking dense cover crops. This has re-
sulted in much better control than where such cover was stand-
ing at time of application.
Since only general outside tree coverage is required, tractors
may pull sprayers at two to three miles per hour. With sprayers
such as the Speed Sprayer, Hardie Mist Sprayer (6) or other
similar machines, nozzles may be arranged to apply the bulk
of the spray to the lower % of the tree and to the cover crop.
As little as 50 to 100 gallons of spray may be used per acre.
If it is desired to spray insecticides for grasshopper control with
other standard materials in a regular application, this may be
done. However, care must be taken to prevent excessive in-
secticide costs. Only enough toxicant should be used to obtain







Florida Agricultural Experiment Stations


the required amount per acre, even though as much as 1,000
gallons per acre of the dilute mixture may be applied.

GRASSHOPPERS OF LESSER ECONOMIC IMPORTANCE
Numerous species of grasshoppers are found at one time or
another in citrus groves. Few ever present an economic prob-
lem. In addition to the American grasshopper, two species have
been common enough for control measures to be applied and
these will be mentioned separately. The other species will be
discussed together, since they are rarely present in large num-
bers in citrus groves.

EASTERN LUBBER GRASSHOPPER
The Eastern lubber, Romalea microptera (Beauvois), is com-
mon in many citrus groves during spring and summer months.
This grasshopper is most plentiful in groves adjacent to low
marshy land. During the summer literally hundreds of these
grasshoppers may be seen sunning themselves on the roads be-
tween the Ridge section and the Florida East Coast.
Lubbers overwinter in the egg stage and hatching usually
begins early in February. The nymphs are almost solid black
with yellow and occasional red markings. These are the grass-
hoppers which are commonly found feeding on amaryllis and
dooryard shrubbery in the spring. The nymphs pass through
five instars before attaining adulthood and reach maturity dur-
ing May and June in most years. Late first and second instar
nymphs collected in April 1951 and caged in the laboratory re-
quired 15 to 20 days for each instar and became adults in early
June (Fig. 8). Although adults have wings they are incapable
of flight. Copulation may be noted in late June and oviposition
follows. In 1951 the majority of females had mature ovaries
on July 20. These eggs do not hatch until the following spring
and thus they complete only one generation per year.
It is only rarely that lubber grasshoppers damage citrus.
Nymphs have been observed feeding on young trees and in some
instances have completely defoliated newly set citrus trees.
However, large trees are not materially affected by them. They
are slow and sluggish in their movements and apparently not
particularly voracious, so that, in spite of the large size of the
grasshopper, large amounts of leaf area are not consumed.
Since the lubber is an extremely large grasshopper, excessive







Florida Agricultural Experiment Stations


the required amount per acre, even though as much as 1,000
gallons per acre of the dilute mixture may be applied.

GRASSHOPPERS OF LESSER ECONOMIC IMPORTANCE
Numerous species of grasshoppers are found at one time or
another in citrus groves. Few ever present an economic prob-
lem. In addition to the American grasshopper, two species have
been common enough for control measures to be applied and
these will be mentioned separately. The other species will be
discussed together, since they are rarely present in large num-
bers in citrus groves.

EASTERN LUBBER GRASSHOPPER
The Eastern lubber, Romalea microptera (Beauvois), is com-
mon in many citrus groves during spring and summer months.
This grasshopper is most plentiful in groves adjacent to low
marshy land. During the summer literally hundreds of these
grasshoppers may be seen sunning themselves on the roads be-
tween the Ridge section and the Florida East Coast.
Lubbers overwinter in the egg stage and hatching usually
begins early in February. The nymphs are almost solid black
with yellow and occasional red markings. These are the grass-
hoppers which are commonly found feeding on amaryllis and
dooryard shrubbery in the spring. The nymphs pass through
five instars before attaining adulthood and reach maturity dur-
ing May and June in most years. Late first and second instar
nymphs collected in April 1951 and caged in the laboratory re-
quired 15 to 20 days for each instar and became adults in early
June (Fig. 8). Although adults have wings they are incapable
of flight. Copulation may be noted in late June and oviposition
follows. In 1951 the majority of females had mature ovaries
on July 20. These eggs do not hatch until the following spring
and thus they complete only one generation per year.
It is only rarely that lubber grasshoppers damage citrus.
Nymphs have been observed feeding on young trees and in some
instances have completely defoliated newly set citrus trees.
However, large trees are not materially affected by them. They
are slow and sluggish in their movements and apparently not
particularly voracious, so that, in spite of the large size of the
grasshopper, large amounts of leaf area are not consumed.
Since the lubber is an extremely large grasshopper, excessive








A I


-I


/ /I// //I.I /! fi '
Fig. 8.-Various stages in the life cycle of the Eastern lubber grass-
hopper. Top to bottom: first and second instars; second and third instars;
third and fourth instars; fifth instar; and adult female. As nymphs these
are black with yellow or red markings. As adults they are a brilliant
yellow with red and black markings.


<*~


I I t t II


R







Florida Agricultural Experiment Stations


amounts of insecticide are required for satisfactory control.
The dosages recommended for S. americana americana should
be increased (50 to 100 percent) if lubbers are to be controlled
(Table 3).
RED-LEGGED GRASSHOPPER
The red-legged grasshopper (Fig. 9), Melanoplus femur-
rubrum propinquus Scudder, is a very common grasshopper over
the entire citrus area. They will occasionally damage young
trees and may be so numerous as to cause alarm to growers on
occasion. They appear to prefer the cover crop to citrus foliage,
and thus damage is minimized. This particular species prob-
ably has two generations per year but its life cycle is not defi-
nitely known. It apparently overwinters in the egg stage and
eggs hatch quite early in the spring. They have been noted
hatching as early as late January in some groves and the nymphs
have reached adulthood by the middle of March. It is probable
that a second generation, and possibly a third, occurs during
the summer months. However, definite information concern-
ing this has not been established.



r ~"







Fig. 9.-Male and female adults of the red-legged grasshopper.

On one occasion these grasshoppers were present in sufficient
numbers in a grove near Haines City to allow experiments in
insecticide control to be undertaken. It was found that they
could be readily controlled with only two-thirds the dosage
recommended for the control of S. americana americana.

OTHER MINOR SPECIES
Two other species appear to have life cycles similar to that
of M. femur-rubrum. These are Paroxya atlantica atlantica
Scudder (Fig. 10) and Dichromorpha viridis (Scudder) (Fig.
11). Nymphs of these species are found hatching in the spring







Florida Agricultural Experiment Stations


amounts of insecticide are required for satisfactory control.
The dosages recommended for S. americana americana should
be increased (50 to 100 percent) if lubbers are to be controlled
(Table 3).
RED-LEGGED GRASSHOPPER
The red-legged grasshopper (Fig. 9), Melanoplus femur-
rubrum propinquus Scudder, is a very common grasshopper over
the entire citrus area. They will occasionally damage young
trees and may be so numerous as to cause alarm to growers on
occasion. They appear to prefer the cover crop to citrus foliage,
and thus damage is minimized. This particular species prob-
ably has two generations per year but its life cycle is not defi-
nitely known. It apparently overwinters in the egg stage and
eggs hatch quite early in the spring. They have been noted
hatching as early as late January in some groves and the nymphs
have reached adulthood by the middle of March. It is probable
that a second generation, and possibly a third, occurs during
the summer months. However, definite information concern-
ing this has not been established.



r ~"







Fig. 9.-Male and female adults of the red-legged grasshopper.

On one occasion these grasshoppers were present in sufficient
numbers in a grove near Haines City to allow experiments in
insecticide control to be undertaken. It was found that they
could be readily controlled with only two-thirds the dosage
recommended for the control of S. americana americana.

OTHER MINOR SPECIES
Two other species appear to have life cycles similar to that
of M. femur-rubrum. These are Paroxya atlantica atlantica
Scudder (Fig. 10) and Dichromorpha viridis (Scudder) (Fig.
11). Nymphs of these species are found hatching in the spring







Grasshoppers in Citrus Groves


and they reach the adult stage at about the same time as M.
femur-rubrum. P. atlantica atlantica resembles M. femur-rubrum
but usually can be differentiated upon the basis of pronotal
size and the coloration of the wings. Paroxya is more delicate
and the pronotum (the collar-like structure behind the head)
is not as wide as in M. femur-rubrum. Dichromorpha viridis is
a short-winged species which has either a green or a brown
phase, and specimens of both colors will be found in the same
area.











Fig. 10.-Adults of the genus Paroxya. Left, male of P. atlantica atlan':ca.
Right, female of P. clavuliger.

Whether or not either of these species undergoes a second
generation is not known, but from the time of hitch it is as-
sumed that the winter is passed in the egg stage, and probably
more than one generation occurs. They have not been observed
doing economic damage.






\ it, rl^-pl0 lV-




Fig. 11.-Nymph and female adult of Dichromorpha viridis, a short-winged
species characterized by the sharp angle of the head.

Paroxya clavuliger (Serville) (Fig. 10) has been noted in
groves during late summer. No information concerning its life
cycle is available.






Florida Agricultural Experiment Stations


1111T [fill 1^111 I I


Fig. 12.-Adult female of the species Fig. 13. Adult female of the species
Schistocerca damnifica calidior. Chortaphaga anstralior.

Schistocerca damnifica calidior Rehn and Hebard (Fig. 12)
and Schistocerca obscura (Fab.) (Fig. 14) both have been ob-
served in citrus groves. No information concerning their life
cycle in citrus groves in Florida has been ascertained. Duck (2)
has published on the bionomics of S. obscure. So far as is
known they are not of economic importance to Florida citri-
culture.












Fig. 14.-Adults of Schistocerca obscure. Female left, male right. The
body of this grasshopper is green, the wings brown.

Chortaphaga australior Rehn and Hebard (Fig. 13) is also
present in citrus groves. It is a colorful species with dusty
brown markings on the wings and colored stripes on the legs.
While it may be commonly found, it is never in great abundance
and so far as is known does not cause economic injury.

SUMMARY
A severe outbreak of the American grasshopper, Schistocerca
americana americana (Drury), in 1947 and 1948 emphasized
the need for information concerning the biology and control of
grasshoppers found in citrus groves in Florida. The American







Grasshoppers in Citrus Groves


grasshopper has two generations per year and may be controlled
by judicious cultivation or by the use of insecticides. Other
grasshoppers of lesser importance to citrus growers are pictured
and discussed.



ACKNOWLEDGMENTS

The authors express their appreciation for identifications by
G. W. Dekle, Florida State Plant Board; for identifications and
help on the technical aspects of the bulletin from Dr. Irving J.
Cantrall of the University of Michigan; and to Mrs. Madge
Collier of the Citrus Station for making the photographs for
this publication.



LITERATURE CITED

1. BLATCHLEY, W. S. Orthoptera of Northeastern America. Indianapolis.
The Nature Publishing Co., pp. 312-314. 1920.
2. DUCK, L. G. The Bionomics of Schistocerca obscura (Fabr.). Jour.
Kan. Ent. Soc. 17: 105-119. 1944.
3. GRIFFITHS, J. T., JR., and J. R. KING. Comparative Compatibility and
Residual Toxicity of Organic Insecticides as Based on Grasshopper
Control. Jour. Econ. Ent. 41: 389-392. 1948.
4. GRIFFITHS, J. T., JR., J. R. KING and W. L. THOMPSON. Grasshopper
Control in Citrus Groves in Florida. Fla. St. Hort. Soc. 60:
80-86. 1947.
5. GRIFFITHS, J. T., JR., H. J. REITZ and R. W. OLSEN. Off-Flavor Pro-
duced in Florida Orange Juice After Application of New Organic
Insecticides. Agr. Chem. 5(9): 41-43, 99. 1950.
6. GRIFFITHS, J. T., JR., C. R. STEARNS, JR., and W. L. THOMPSON. Possi-
bilities for the Use of Concentrated Sprays on Citrus in Florida.
Proc. Fla. St. Hort. Soc. 63: 53-60. 1950.
7. KING, J. R., and J. T. GRIFFITHS, JR. Results of the Use of Concen-
trated Sprays in Citrus Groves in Florida. The Fla. Ent. 31: 29-34.
1948.
8. MEDLER, J. T., and T. R. CHAMBERLAIN. Low-Volume Sprays for Grass-
hopper Control in Alfalfa-Seed Fields. Jour. Econ. Ent. 43:
185-188. 1950.
9. PARKER, J. R. Grasshoppers and Their Control. USDA Farm Bul.
No. 1828. June, 1939.
10. SCUDDER, S. H. The Orthopteran Genus Schistocerca. Proc. Am. Acad.
Arts and Sci. 34: 441-476. 1899.








26 Florida Agricultural Experiment Stations

11. THOMPSON, W. L., J. T. GRIFFITHS, JR., and J. W. SITES. Progress
Report on Parathion as an Insecticide for Florida Citrus. Proc.
Fla. St. Hort. Soc. 62: 100-105. 1949.
12. WAKELAND, C., and J. R. PARKER. Grasshopper Control with Aldrin,
Chlordane, and Toxaphene. USDA Bur. of Ent. and P1. Quar.
PA-149. Feb. 1951.
13. WATSON, J. R., and E. W. BERGER. Citrus Insects and Their Control.
Fla. Agr. Ext. Ser. Bul. 88. 1937.
14. WEINMAN, C. J., and G. C. DECKER. Chlorinated Hydrocarbon Insecti-
cides Used Alone and in Combinations for Grasshopper Control.
Jour. Econ. Ent. 42: 135-142. 1949.




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