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August, 1947
UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATION
HAROLD MOWRY, Director
GAINESVILLE, FLORIDA
A Contribution from the Vegetable Crops Laboratory
Bradenton, Florida
DDT TREATMENTS FOR CONTROL
OF MOLE-CRICKETS IN SEEDBEDS
By E. G. KELSHEIMER
Fig. 1.-The most widespread and destructive mole-crickets. Left,
Puerto Rican (Scapteriscus vicinus Scudd.); right, Southern (S. acletus
R. & H.). (Photograph by D. G. A. Kelbert.)
Single copies free to Florida residents upon request to
AGRICULTURAL EXPERIMENT STATION
GAINESVILLE, FLORIDA
Bulletin 434
BOARD OF CONTROL
J. Thos. Gurney, Chairman, Orlando
N. B. Jordan, Quincy
Thos. W. Bryant, Lakeland
M. L.. Mershon, Miami
J. Henson Markham. Jacksonville
J. T. Diamond, Secretary, Tallahassee
EXECUTIVE STAFF
John J. Tigert, M.A., LL.D., President of the
University3
H. Harold Hume, D.Sc., Provost for Agricul-
ture
Harold Mowry, M.S.A., Director
L. O. Gratz. Ph.D., Asst. Dir., Research
W. M. Fifield, M.S., Asst. Dir., Admin.
J. Francis Cooper, M.S.A., Editors
Clyde Beale, A.B.J., Associate Editor'
Jefferson Thomas, Assistant Editors
Ida Keeling Cresap, Librarian
Ruby Newhall, Administrative Managers
K. H. Graham, LL.D., Business Managers
Claranelle Alderman, Accountant'
MAIN STATION, GAINESVILLE
AGRONOMY
W. E. Stokes, M.S., Agronomist'
Fred If. Hull, Ph.D., Agronomist
G. E. Ritchey, M.S., Agronomists
G. B. Killinger, Ph.D., Agronomist
H. C. Harris, Ph.D., Agronomist
W. A. Carver, Ph.D., Associate
Fred A. Clark, B.S., Assistant
ANIMAL INDUSTRY
A. L. Shealy, D.V.M., An. Industrialist'1
R. B. Becker, Ph.D., Dairy Husbandman'
E. L. Fouts, Ph.D., Dairy Technologist'
D. A. Sanders, D.V.M., Veterinarian
M. W. Emmel, D.V.M., Veterinarian'
L. E. Swanson, D.V.M., Parasitologist
N. R. Mehrhof, M.Agr., Poultry Hush.'
G. K. Davis, Ph.D., Animal Nutritionist
R. S. Glasscock, Ph.D., An. Husbandman
P T. Dix Arnold, M.S.A., Asst. Dairy Husb.'
C. L. Comar, Ph.D., Asso. Biochemist
L. E. Mull, M.S., Asst. in Dairy Tech.6
Katherine Boney, B.S., Asst. Chem.
J. C. Driggers, B.S.A., Asst. Poultry Hush.
Glenn Van Ness, D.V.M., Asso. Poultry
Pathologist
S. John Folks, B.S.A., Asst. An. Husb.
W. A. Krienke, M.S., Asso. in Dairy Mfs.
ECONOMICS, AGRICULTURAL
C. V. Noble, Ph.D., Agri. Economist' *
Zach Savage, M.S.A., Associates
A. H. Spurlock, M.S.A., Associate
I. E. Alleger, M.S., Associate
D. L. Brooke, M.S.A., Associate
Orlando, Florida (Cooperative USDA)
G. Norman Rose, B.S., Asso. Agr. Economist
J. C. Townsend, Jr., B.S.A., Agr. Statistician*
J. B. Owens, B.S.A., Agr. Statistician2
W. S. Rowan, M.S., Asst. Agr. Statistician2
ECONOMICS. HOME
Ouida D. Abbott, Ph.D., Home Econ.'
R. B. French, Ph.D., Biochemist
ENTOMOLOGY
A. N. Tissot, Ph.D., Entomologist'
H. E. Bratley, M.S.A., Assistant
HORTICULTURE
G. H. Blackmon, M.S.A., Horticulturist'
F. S. Jamison, Ph.D., Truck Hort.
Byron E. Janes, Ph.D., Asso. Hort.
R. A. Dennison, Ph.D., Asso. Hort.
R. K. Showalter, M.S., Asso. Hort.
R. J. Wilmot, M.S.A., Asst. Hort.
R. D. Dickey, M.S.A., Asst. Hort.
Victor F. Nettles, M.S.A., Asst. Hort.
F. S. Lagasse, Ph.D., Asso. Hort.2
PLANT PATHOLOGY
W. B. Tisdale, Ph.D., Plant Pathologist'
Phares Decker, Ph.D., Asso. Plant Path.
Erdman West, M.S., Mycologist and Botanist
Lillian E. Arnold, M.S., Asst. Botanist
SOILS
F. B. Smith, Ph.D., Microbiologist s
Gaylord M. Volk, Ph.D., Chemist
J. R. Henderson, M.S.A., Soil Technologist
J. R. Neller, Ph.D., Soils Chemist
Nathan Gammon, Jr., Ph.D., Soils Chemist
C. E. Bell, Ph.D., Associate Chemist
L. H. Rogers, Ph.D., Biochemist
R. A. Carrigan, B.S., Asso. Biochemist
H. W. Winsor, B.S.A., Assistant Chemist
Geo. D. Thornton, M.S., Asso. Microbiologist
R. E. Caldwell, M.S.A., Soil Surveyor
Wade McCaII, B.S.A., Asst. Chemist
J. B. Cromartie, B.S.A., Soil Surveyor
1 Head of Department.
2 In cooperation with U. S. D. A.
Cooperative, other divisions, U. of F.
4 In Military Service.
6 On leave.
BRANCH STATIONS
NORTH FLORIDA STATION, QUINCY
J. D. Warner, M.S., Vice-Director in Charge
R. R. Kincaid, Ph.D., Plant Pathologist
W. H. Chapman, M.S., Asso. Agron.
R. C. Bond, M.S.A., Asso. Agronomist
L. G. Thompson, Ph.D., Soils Chemist
Frank S. Baker, Jr., B.S., Asst. An. Hush.
Mobile Unit. Monticello
R. W. Wallace, B.S., Associate Agronomist
Mobile Unit, Marianna
R. W. Lipscomb, M.S.. Associate Agronomist
Mobile Unit. Wewahitchka
J. B. White, B.S.A., Associate Agronomist
Mobile Unit, DeFuniak Springs
R. L. Smith, M.S., Associate Agronomist
CITRUS STATION, LAKE ALFRED
A. F. Camp, Ph.D., Vice-Director in Charge
W. L. Thompson, B.S., Entomologist
J. T. Griffiths, Ph.D., Asso. Entomologist
R. F. Suit. Ph.D., Plant Pathologist
E. P. Ducharme, M.S., Plant Pathologist5
J. E. Benedict, B.S., Asst. Horticulturist
B. R. Fudge, Ph.D., Associate Chemist
C. R. Stearns, Jr., B.S.A., Asso. Chemist
James K. Colehour, M.S., Asst. Chemist
T. W. Young, Ph.D., Asso. Horticulturist
J. W. Sites, M.S.A., Horticulturist
H. O. Sterling, B.S., Asst. Horticulturist
J. A. Grangt B.S.A., Asst. Horticulturist
H. J. Reitz, M.S., Asso. Horticulturist
Francine Fisher, M.S., Asst. PI. Path.
I. W. Wander, Ph.D., Soil Chemist
A. E. Willson, B.S.A., Asso. Soil Phys.
R. W. Jones, Asst. Plant Path.
J. W. Kesterson, M.S., Asso. Chemist
C. W. Houston, Ph.D., Asso. Chemist
EVERGLADES STA., BELLE GLADE
R. V. Allison, Ph.D., Vice-Director in Charge
F. D. Stevens, B.S., Sugarcane Agron.
Thomas Bregger, Ph.D., Sugarcane
Physiologist
B. S. Clayton, B.S.C.E., Drainage Eng.2
W. T. Forsee, Jr., Ph.D., Chemist
R. W. Kidder, M.S., Asso. An. Hush.
T. C. Erwin, Assistant Chemist
Roy A. Bair, Ph.D., Agronomist
C. C. Seale, Asso. Agronomist
L. O. Payne. B.S.A., Asst. Agronomist
Russel Desrosiers. M.S., Asst. Plant Path.
N. C. Hayslip, B.S.A., Asso. Entomologist
J. C. Hoffman, M.S., Asso. Hort.
C. B. Savage, M.S.A., Asst. Hort.
Geo. Van den Berghe, B.S., Asst. Fiber Tech.
SUB-TROPICAL STA., HOMESTEAD
Geo. D. Ruehle, Ph.D., Vice-Director in
Charge
D. O. Wolfenbarger, Ph.D., Entomologist
R. W. Harkness, Ph.D., Asst. Chemist
W. CENT. FLA. STA.. BROOKSVILLE
C. D. Gordon, Ph.D., Geneticist in Charges
RANGE CATTLE STATION, ONA
W. G. Kirk, Ph.D.. Vice-Director in Charge
E. M. Hodges, Ph.D., Associate Agronomist
D. W. Jones, B.S., Asst. Soil Tech.
E. R. Felton. B.S.A., Asst. An. Hush.
CENTRAL FLORIDA STATION, SANFORD
R. W. Ruprecht, Ph.D., Vice-Director in
Charge
A. Alfred Foster, Ph.D., Asso. Pl. Path.
J. W. Wilson, Sc.D., Entomologist
Ben F. Whitner, Jr., B.S.A., Asst. Hort.
WEST FLORIDA STATION, MILTON
H. W. Lundy, B.S.A., Asso. Agronomist
FIELD STATIONS
Leesburg
G. K. Parris, Ph.D.. Plant Path. in Charge
Plant City
A. N. Brooks, Ph.D., Plant Pathologist
Hastings
A. H. Eddins, Ph.D., Plant Path. in Charge
E. N. McCubbin, Ph.D., Horticulturist
Monticello
S. 0. Hill, B.S.. Asst. Entomologist
A. M. Phillips, B.S., Asso. Entomologist'
Bradenton
J. R. Beckenbach. Ph.D., Horticulturist in
Charge
E. G. Kelsheimer, Ph.D., Entomologist
David G. Kelbert, Asso. Horticulturist
E. I.. Spencer, Ph.D., Soils Chemist
Robert O. Magie, Ph.D., Pl. Path., Glad. Inv.
J. M. Walter, Ph.D., Plant Path.
Donald S. Burgis, M.S.A., Asst. Hort.
Lakeland
Warren O. Johnson, B.S., Meteorologists
I Head of Department.
2 In cooperation with U. S.
SCooperative, other divisions, U. of F.
'In Military Service.
6 On leave.
TABLE 1.-TREATMENTS AND TOTAL LINEAL FEET OF MOLE-CRICKET
BURROWINGS, FIRST TEST.
Treat- Actual Total
ment Pounds Lineal
Num- Treatment DDT Feet of
her per Acre Runs**
1 *DDT 20% emulsion-1 gal. to 100 gals.
water, applied 1 gal. per 10 sq. ft. ................ 69.7 68
2 DDT 20% emulsion-1%' gal. to 100 gals.
water, applied 1 gal. per 10 sq. ft. ............... 104.5 87
3 DDT 40% spray--1%/ lbs. to 100 gals. water,
applied 1 gal. per 10 sq. ft ............................ 21.8 94
4 DDT 20% dust--50 lbs. per acre +;fertilizer
applied separately ........................................ 10.0 97
5 DDT 20% dust-150 lbs. per acre + fertilizer
mixed together ...................................- ..... 30.0 108
6 DDT 40% spray-2% Ibs. to 100 gals. of
water, applied 1 gal. per 10 sq. ft. ............... 43.6 113
7 DDT 20% emulsion-V2 gal. to 100 gals.
water, applied 1 gal. per 10 sq. ft. ....... .. 34.8 114
8 DDT 20% dust-150 lbs. per acre + fertilizer
applied separately ....................................... ... 30.0 134
9 DDT 20% dust-100 lbs. per acre + fertilizer,
applied separately ........................................ 20.0 163
10 DDT 20% dust-100 lbs. per acre + fertilizer
mixed together ........................ .................... 20.0 185
11 DDT 20% dust-50 lbs. per acre + fertilizer
mixed together ........................................... ... 10.0 194
12 Check-no treatment-fertilizer only ........... 631
Treatment totals must differ by 51 to be significant.
All DDT compoundings (Gesarol + AK40) were supplied gratis by the Geigy Com-
pany. Treatments 1, 2 and 7 Gesarol emulsion; Treatments 3 and 6 AK40 spray; all
remaining treatments were Gesarol A20 dust.
** Totals represent the sum of 4 replications (40 sq. ft.) and the total of 13 separate
readings over a period of 1 month.
DDT TREATMENTS FOR CONTROL OF MOLE-
CRICKETS IN SEEDBEDS
By E. G. KELSHEIMER, Entomologist
Vegetable Crops Laboratory
Florida Agricultural Experiment Station
Bradenton, Florida
CONTENTS
Page
General Description of Mole-Crickets ................................. 5
Species of Mole-Crickets in Florida ..................................... 5
Previous Control Methods ....................................................... 6
Experimental Technique ....................... ............. ........... 6
Mole-Cricket Control ...................................... ....... ......... 8
Effects on Germination ...........................- .... ......... ...-.. 15
Effects of Storage on DDT + Fertilizer ............................. 15
Summary and Recommendations ........................... ........- 15
Practically every Florida grower is acquainted with the bur-
rowing and damage caused by mole-crickets. The damage to
seedbeds alone in the affected areas annually amounts to thou-
sands of dollars. One commercial nurseryman estimated his
loss in statice seedbeds at $1,000, $300 of which was for seed
alone. Wisecup and Hayslip (3)1 in 1943 estimated the average
annual losses due to mole-crickets in North Carolina, South
Carolina, Georgia, Florida, Alabama and Mississippi at nearly
$2,000,000, including the damage to crops and the cost of con-
trol in seedbeds and in fields.
General Description of Mole-Crickets
Mole-crickets belong to the same family as the field crickets
but do not closely resemble them. They are subterranean insects,
coming to the surface at night for feeding or flight, or if flooded
out by heavy rains or irrigation. The full-grown mole-cricket
is approximately 11/2 inches in length and 1/4 inch or more in
width. The insects are covered with fine hair which gives them
a velvety appearance. The forepart of the body has a hard
covering which protects it while burrowing in the soil. The
hind part of the body is soft.
Species of Mole-Crickets in Florida
-There are 4 species of mole-crickets in Florida, of which 2
are of economic importance. Species of lesser importance are
the short-winged mole-cricket, Scapteriscus abbreviatus Scudd.,
which is found only in the southern part of Florida, and the
northern mole-cricket, Gryllotalpa hexadactyla Perty, which is
1 Italic figures in parentheses refer to "Literature Cited."
DDT TREATMENTS FOR CONTROL OF MOLE-
CRICKETS IN SEEDBEDS
By E. G. KELSHEIMER, Entomologist
Vegetable Crops Laboratory
Florida Agricultural Experiment Station
Bradenton, Florida
CONTENTS
Page
General Description of Mole-Crickets ................................. 5
Species of Mole-Crickets in Florida ..................................... 5
Previous Control Methods ....................................................... 6
Experimental Technique ....................... ............. ........... 6
Mole-Cricket Control ...................................... ....... ......... 8
Effects on Germination ...........................- .... ......... ...-.. 15
Effects of Storage on DDT + Fertilizer ............................. 15
Summary and Recommendations ........................... ........- 15
Practically every Florida grower is acquainted with the bur-
rowing and damage caused by mole-crickets. The damage to
seedbeds alone in the affected areas annually amounts to thou-
sands of dollars. One commercial nurseryman estimated his
loss in statice seedbeds at $1,000, $300 of which was for seed
alone. Wisecup and Hayslip (3)1 in 1943 estimated the average
annual losses due to mole-crickets in North Carolina, South
Carolina, Georgia, Florida, Alabama and Mississippi at nearly
$2,000,000, including the damage to crops and the cost of con-
trol in seedbeds and in fields.
General Description of Mole-Crickets
Mole-crickets belong to the same family as the field crickets
but do not closely resemble them. They are subterranean insects,
coming to the surface at night for feeding or flight, or if flooded
out by heavy rains or irrigation. The full-grown mole-cricket
is approximately 11/2 inches in length and 1/4 inch or more in
width. The insects are covered with fine hair which gives them
a velvety appearance. The forepart of the body has a hard
covering which protects it while burrowing in the soil. The
hind part of the body is soft.
Species of Mole-Crickets in Florida
-There are 4 species of mole-crickets in Florida, of which 2
are of economic importance. Species of lesser importance are
the short-winged mole-cricket, Scapteriscus abbreviatus Scudd.,
which is found only in the southern part of Florida, and the
northern mole-cricket, Gryllotalpa hexadactyla Perty, which is
1 Italic figures in parentheses refer to "Literature Cited."
Florida Agricultural Experiment Station
seldom.found except in localities having wet, heavy soils. The
most numerous species in Manatee County is the Southern mole-
cricket, S. acletus R. & H., which outnumbers by 10 to 1 the
Puerto Rican mole-cricket or change, S. vicinus Scudd. These
are the most destructive insects and all tests have been con-
ducted with them.
The Southern mole-cricket, S. acletus, is greenish gray with
light marking on the thorax (Fig. 1). It is extremely restless
and active, burrowing into the ground the instant it is exposed.
It is active all year except during extremely cold spells. The
Puerto Rican mole-cricket, S. vicinus, is creamy to dark brown
in color (Fig. 1). This species is sluggish and "plays possum"
when exposed or disturbed.
According to Hayslip (1), the life cycle for both species is
about 1 year. The egg-laying period for S. acletus is 61 days,
compared with 33 days for S. vicinus. The eggs are deposited
in an earthen cell averaging from 20 to 22 eggs per cell and 3
to 4 cells per female. The incubation period varies according
to the temperature, with about 20 days for both species being
the average if the weather is warm, and up to 35 days if colder.
Previous Control Methods
Baiting has been in use for a number of years and many hun-
dreds of tons of bait have been distributed in Florida for the
control of mole-crickets. The writer (2) has been interested
in soil insecticides as a possible control for the insects in seed-
beds. Many products have been tried as soil insecticides. Many
were immediately discarded because of the long time interval
between application and safety of seeding, others hurt germina-
tion or growth of seedlings, and many were no good at all.
Among the products tested was naphthalene which was found
promising and was recommended as a repellent to keep the in-
sects from the seedbeds (2).
In 1945 DDT (dichloro-diphenyl-trichloroethane) was made
available for agricultural purposes. This material and other
insecticides have been tested for the commercial control of mole-
crickets in seedbeds. The results are reported in this bulletin..
Experimental Technique
The materials tested were all commercially available products
prepared for use as dust or spray insecticides. There were 2
forms of the latter, 1 being wettablee", the other in emulsifiable
Florida Agricultural Experiment Station
seldom.found except in localities having wet, heavy soils. The
most numerous species in Manatee County is the Southern mole-
cricket, S. acletus R. & H., which outnumbers by 10 to 1 the
Puerto Rican mole-cricket or change, S. vicinus Scudd. These
are the most destructive insects and all tests have been con-
ducted with them.
The Southern mole-cricket, S. acletus, is greenish gray with
light marking on the thorax (Fig. 1). It is extremely restless
and active, burrowing into the ground the instant it is exposed.
It is active all year except during extremely cold spells. The
Puerto Rican mole-cricket, S. vicinus, is creamy to dark brown
in color (Fig. 1). This species is sluggish and "plays possum"
when exposed or disturbed.
According to Hayslip (1), the life cycle for both species is
about 1 year. The egg-laying period for S. acletus is 61 days,
compared with 33 days for S. vicinus. The eggs are deposited
in an earthen cell averaging from 20 to 22 eggs per cell and 3
to 4 cells per female. The incubation period varies according
to the temperature, with about 20 days for both species being
the average if the weather is warm, and up to 35 days if colder.
Previous Control Methods
Baiting has been in use for a number of years and many hun-
dreds of tons of bait have been distributed in Florida for the
control of mole-crickets. The writer (2) has been interested
in soil insecticides as a possible control for the insects in seed-
beds. Many products have been tried as soil insecticides. Many
were immediately discarded because of the long time interval
between application and safety of seeding, others hurt germina-
tion or growth of seedlings, and many were no good at all.
Among the products tested was naphthalene which was found
promising and was recommended as a repellent to keep the in-
sects from the seedbeds (2).
In 1945 DDT (dichloro-diphenyl-trichloroethane) was made
available for agricultural purposes. This material and other
insecticides have been tested for the commercial control of mole-
crickets in seedbeds. The results are reported in this bulletin..
Experimental Technique
The materials tested were all commercially available products
prepared for use as dust or spray insecticides. There were 2
forms of the latter, 1 being wettablee", the other in emulsifiable
Florida Agricultural Experiment Station
seldom.found except in localities having wet, heavy soils. The
most numerous species in Manatee County is the Southern mole-
cricket, S. acletus R. & H., which outnumbers by 10 to 1 the
Puerto Rican mole-cricket or change, S. vicinus Scudd. These
are the most destructive insects and all tests have been con-
ducted with them.
The Southern mole-cricket, S. acletus, is greenish gray with
light marking on the thorax (Fig. 1). It is extremely restless
and active, burrowing into the ground the instant it is exposed.
It is active all year except during extremely cold spells. The
Puerto Rican mole-cricket, S. vicinus, is creamy to dark brown
in color (Fig. 1). This species is sluggish and "plays possum"
when exposed or disturbed.
According to Hayslip (1), the life cycle for both species is
about 1 year. The egg-laying period for S. acletus is 61 days,
compared with 33 days for S. vicinus. The eggs are deposited
in an earthen cell averaging from 20 to 22 eggs per cell and 3
to 4 cells per female. The incubation period varies according
to the temperature, with about 20 days for both species being
the average if the weather is warm, and up to 35 days if colder.
Previous Control Methods
Baiting has been in use for a number of years and many hun-
dreds of tons of bait have been distributed in Florida for the
control of mole-crickets. The writer (2) has been interested
in soil insecticides as a possible control for the insects in seed-
beds. Many products have been tried as soil insecticides. Many
were immediately discarded because of the long time interval
between application and safety of seeding, others hurt germina-
tion or growth of seedlings, and many were no good at all.
Among the products tested was naphthalene which was found
promising and was recommended as a repellent to keep the in-
sects from the seedbeds (2).
In 1945 DDT (dichloro-diphenyl-trichloroethane) was made
available for agricultural purposes. This material and other
insecticides have been tested for the commercial control of mole-
crickets in seedbeds. The results are reported in this bulletin..
Experimental Technique
The materials tested were all commercially available products
prepared for use as dust or spray insecticides. There were 2
forms of the latter, 1 being wettablee", the other in emulsifiable
DDT Treatments for Control of Mole-Crickets
oil. All were organic products with some insecticidal reputa-
tion, the material receiving the most complete trial being DDT.
The various treatments are listed in subsequent tables.
The Gesarol emulsion is a 25 percent DDT in an emulsifiable
oil. The A20 dust is a 20 percent DDT in an inert base. The
AK40 is a 40 percent wettable spray material. All of the above
are manufactured by the Geigy Company. The Deenol 25 is a
25 percent DDT in an emulsifiable oil and the Deenate 50W is
a 50 percent DDT spray material, both of which are manufac-
tured by The DuPont Company. Rhothane (dichloro-diphefyl-
dichloroethane), a material chemically somewhat similar to
DDT, was used at a 25 percent strength in emulsifiable oil.
It is manufactured by the Rohm & Haas Company.
The benzene hexachloride is a 50 percent wettable spray ma-
terial compounded by The Niagara Company under that name.
It had a 6% gamma isomer content.
There were 4 experiments in all. In 3 of the experiments
some treatments had DDT mixed in and applied with the fer-
tilizer. All seedbeds received 1000 pounds peracre of a com-
mercial 4-5-7 mixture which was applied before the insecticide
was, except when the 2 were mixed.
Dusts were distributed over the bed surface as evenly as
possible by hand and worked into the soil with a potato fork.
The liquids were all applied at the rate of 1 gallon of the pre-
pared solution to 10 square feet of bed. These were applied by
sprinkling can and sprinkled on both lengthwise and crosswise
of the bed to insure even distribution. No water seal was used
with either dust or liquid treatments.
All 4 experiments were laid out in replicated and randomized
blocks, so that approved statistical methods could be used with
the data. Only totals of all replicates are given in the tables.
Seedbeds were located in those areas of the greatest mole-
cricket activity. After the seedbed was constructed and the
plots were marked off a light application of wheat bran was
spread evenly over the entire surface area. This insured an
even distribution of insect burrowings, as noted by readings
taken the following day.
All records were based on the number of feet of runs thrown
up by the mole-crickets at night, since this activity constitutes
the bulk of the damage -caused by these insects. After each
reading the beds were watered down to destroy the tunnels, and
to prepare the plots for more readings the next morning.
Florida Agricultural Experiment Station
Mole-Cricket Control
Experiment 1.-This was a randomized block experiment with
.4 replications. The treatments included are indicated in Table
1 (page 4).
The plots, 1/1,000 acre each, were located on land on which
gladioli had been grown and from which the corms had been
dug recently. There was a heavy and uniform infestation of
mole-crickets in this field. In addition, there was a heavy popu-
lation of the granulate cutworm, Feltia subterranean (F.), and
several nests of ants, so it was possible to observe the effects
of the treatments on these insects as well as on the mole-crickets.
The plots in this test were on raised beds, with 4-foot alleys
separating the plots. The beds were seep irrigated from these
alleys. Care was taken to keep all plots uniformly moist. Meas-
urements were taken from the same 10 square foot areas each
time.
It should be noted in Table 1 that the totals presented repre-
sent the combined measurements of 13 different readings over
a month's time (March 19 to April 16, 1945), and that all 4
replications are totaled, so that 40 square feet of bed are in-
cluded in each total. A total of 68 lineal feet is not much bur-
rowing over a month's time. A single cricket by actual meas-
urement was found to burrow 23 feet in 1 night.
In considering the various forms and quantities of DDT ap-
plied in this test there are several ways that the data in Table 1
can be compared. They have been arranged in direct order as
to measurable control, with the least amount of runs (i.e. the
best control) at the top of the table.
It is obvious from the number of feet of run on the check
plots (Treatment 12) that all DDT treatments gave considerable
control of the mole-crickets. If these other treatments may be
considered with this point in mind, the remaining problem is
only to select the most efficient and least expensive DDT treat-
ment. With a least significant difference of 51, all of the first
7 treatments must be considered equally effective as far as this
experiment is concerned. In terms of the quantity of DDT
applied per acre, these treatments range from 10 pounds to 104.5
pounds. Results secured in Treatment 4 would seem to be out
of line, since larger quantities applied in the same form and
in the same manner did not give as good control.
The most consistently successful materials were the treat-
ments applied with the sprinkling can, and all of these, both
DDT Treatments for Control of Mole-Crickets
the wettable and emulsified forms, gave equivalent control re-
gardless of the amount of DDT applied (from 21.8 pounds to
104.5 pounds).
It was noted that the ants and cutworms were effectively con-
trolled in this test.
Experiment 2.-In this test, in addition to measuring burrows
as a means of control of the mole-crickets, it was desired to
measure the effects of the insecticides on plant growth. It was
also hoped that some of the results of Experiment 1 would be
clarified. The treatments are listed in Table 2.
Again there were 4 replications of 1/1,000 acre plots. In this
test no alleys were left between plots, but instead the plots were
separated by barriers of galvanized iron sunk 6 inches into the
ground and protruding 12 inches above. These barriers kept
the insecticidal materials separate without preventing mole-
crickets from flying in or from burrowing under.
TABLE 2.-TREATMENTS AND TOTAL LINEAL FEET OF MOLE-CRICKET
BURROWINGS, SECOND TEST.
Treat- Actual Total
ment Pounds Lineal
Num- Treatment DDT Feet of
ber per Acre Runs*
1 -DDT 25% emulsion-- gal. to 100 gals.
water applied 1 gal. to 10 sq. ft. .................. 43.5 10
2 DDT 25% emulsion-1 gal. to 100 gals.
water applied 1 gal. to 10 sq. ft. ................ 87.1 13
3 DDT 20% dust-150 Ibs. per acre + fertilizer
mixed together ............................ ................ 30.0 16
4 DDT 25% emulsion-1% gals. to 100 gals.
water, applied 1 gal. to 10 sq. ft. ............... 130.2 17
5 DDT 40% spray-21% lbs. to 100 gals. water
applied 1 gal. to 10 sq. ft. .............................. 43.6 21
6 DDT 20% dust-50 lbs. per acre + fertilizer
mixed together ...................................... ...... 10.0 27
7 DDT 40% spray-1% lbs. to 100 gals. water,
applied 1 gal. to 10 sq. ft. .............................. 21.8 38
8 DDT 20% dust-100 lbs. per acre + fertilizer
mixed together ...................................... ...... 20.0 38
9 DDT 20% dust-100 lbs. per acre + fertilizer
applied separately ...................................... 20.0 48
10 DDT 20% dust-150 lbs. per acre + fertilizer
applied separately ................... ............... 30.0 60
11 DDT 20% dust-50 lbs. per acre + fertilizer
applied separately .................................... 10.0 65
12 Check- fertilizer only ....................................... 123
Treatments must differ by 23.8 to be significant.
The measurements are the total of 5 readings in each treatment of 4 1/1000 acre plots.
All materials were furnished gratis by the Geigy Company.
Florida Agricultural Experiment Station
The plots were artificially infested with S. acletus on Sept.
14, 1945. Subsequent infestations were made to allow for
possible loss by flight or other failure to colonize. The plots
were treated on October 10 and then were seep irrigated. Read-
ings were taken Oct. 23, 24, 25, 26, 1945, and Jan. 24, 1946.
Lettuce plants were set to the plots on Nov. 7, 1945, and har-
vested Jan. 21, 1946, just before the final mole-cricket reading.
There was no mole-cricket activity on plots of Treatments 2 and
4 at the time of the last reading. The entire plot of 1/1,000
acre was measured.
In this second test, with a least significant difference of 23.8
feet of run, the best control was secured with quantities of DDT
ranging from 10 to 130.2 pounds per acre. Control with 10
pounds of DDT per acre showed up in the treatment where fer-
tilizer and DDT were mixed together, as contrasted to the results
secured in the first test in which this treatment was relatively
poor. Treatment 11 in Experiment 2 was good in Experiment
1 and unsatisfactory in the second test.
Treaments consistently in the best control group in both tests
included all 3 in which the emulsifiable oil was used, 150 pounds
per acre of the 20 percent DDT dust mixed with the fertilizer,
and 21/2 pounds of the 40 percent DDT spray material to 100
gallons of water applied with the sprinkling can (43.6 pounds
of DDT per acre).
There were no significant differences between treatments
when yields of lettuce were compared. These data are omitted
in this bulletin. However, the same plots were again treated
with insecticides on January 30, 1946, and planted to snap beans
on Feb. 4. The beans were harvested on April 8, and it was
found that some yields as given in Table 3 were significantly
reduced as compared with the check treatment.
The total actual DDT applied to the soil is given in Table 3.
Of the 5 treatments showing significant decrease, 2 are the
highest applications. Again the 50 pounds of 20 percent DDT
mixed with fertilizer or applied separately is out of line with
the high applications. It is interesting to note that yield from
the plots receiving DDT 25 percent emulsion at the rate of /2
gallon to 100 gallons of water was but slightly numerically less
than yield on the check plots. No mole-cricket readings were
taken on these plots while the beans were growing.
Experiment 3.-In a randomized and 5 replication series of 10
square foot plots, 2 new organic were compared with DDT oil
TABLE 3.-EFFECT OF DDT SOIL TREATMENTS FOR MOLE-CRICKET CONTROL ON YIELD OF GREEN BEANS, APRIL 8, 1946.
Treatment
DDT 20% dust-150 lbs. per acre + fertilizer mixed together ..
DDT 25% emulsion-1 gal, to 100 gals. water applied 1 gal. to
10 sq. ft. ......................................................... ............................
DDT 25% emulsion-1i2 gals. to 100 gals. water applied 1 gal.
to 10 sq. ft. .........................................................................
DDT 20% dust-50 lbs. per acre + fertilizer mixed together ....
DDT 20% dust-50 lbs. per acre + fertilizer applied separately-
DDT 40% spray-11/4 lbs. to 100 gals. water ................................
DDT 20% dust-150 lbs. per acre + fertilizer applied separately
DDT 20% dust-100 lbs. per acre + fertilizer applied separately
DDT 40% spray--/2 lbs. to 100 gals. water ................................
DDT 20% dust-100 lbs. per acre + fertilizer mixed together .
DDT 25% emulsion--% gal. to 100 gals. water applied 1 gal.
to 10 sq. ft. ....................... ............ .................................
Check-fertilizer only ..................... .......................
I Actual Pounds
SDDT per Acre
30.0
87.1
130.2
10.0
10.0
21.8
30.0
20.0
43.6
20.0
43.5
Total Actual
DDT* Applied
to Soil
60
156.8
234.7
20.0
20.0
43.6
60.0
40.0
87.2
40.0
78.3
Treatments must differ by 80.5 to be significant.
* This amount of actual DDT per acre is the summation of 'amounts of DDT in Tables 1 and 2.
Treat-
ment
Num-
ber
Weight of
Beans in
Dekagrams
422
431
435
462
507
510
541
551
553
556
562
589
Florida Agricultural Experiment Station
emulsion and wettable powder. The mixtures with fertilizer
were omitted in this test because of lack of space.
The plots were on a raised bank that served as a dike to keep
the excess run-off rains from flooding the experimental field.
This area was selected not only because the surface was so thor-
oughly plowed up by mole-crickets that no undisturbed place
remained but also because it was more nearly like a commercial
seedbed. The plots could be seep irrigated from both sides.
No barriers were placed between the plots. Plots were sep-
arated by marking the dirt with a V-shaped piece of wood.
Only the actual seedbed was treated. The shoulders and the
ditches were left untreated to permit the crickets access to the
plots.
The materials used and lineal feet of run measured are given
in Table 4. Each plot received 1 gallon of solution on March 26.
In the third test, with a least significant difference of 82.8
feet of run, the 50 percent wettable DDT powders did not give
control comparable to that secured with the emulsifiable oils.
One of the other materials, Rhothane 25, gave equivalent con-
trol. The readings in Table 4 are total length of burrowings
for 23 consecutive days, Sundays excepted, from March 28
through April 26. The seedbeds had many large ant hills,
which were completely eliminated by all treatments.
TABLE 4.-TREATMENTS* AND TOTAL LINEAL FEET OF MOLE-CRICKET
BURROWINGS.
Treat- Actual Total
ment Pounds Lineal
Num- Treatment DDT Feet of
her per Acre Runs**
1 DDT 25% emulsifiable oil-1 gal. to 100 gals.
w ater ...............................................- ................. 87.1 64
2 DDT 25% emulsifiable oil-1 gal. to 100 gals.
water ............................... ............. 87.1 85
3 Rhothane 25-1 gal. to 100 gals. water .......... 93
4 Benzene hexachloride 50W-4 lbs. to 100
gals. w ater ...................................... .......... 150
5 Benzene hexachloride 50W-2 lbs. to 100
gals. water ...................... ........................ 153
6 DDT 50% wettable-4 lbs. to 100 gals. water 87.1 153
7 DDT 50% wettable-2 lbs. to 100 gals. water 43.5 222
8 Check-no treatment ..................................... 296
All treatments were applied at the rate of 1 gal. per 10 sq. ft.
A difference of 82.8 between totals is required for significance.
Materials for treatment 1 (Gesarol 25) were furnished by the Geigy Company; Treat-,
ments 2 (Deenate 25). 6, and 7 (IYeenate 50W) by the Du Pont Company; Treatment 3,
The Rohm and Haas Company and Treatments 4 and 5 by the Niagara Company.
** Totals represent sum of 5 replications (50 so. ft.) from 23 consecutive daily readings
from the date treatments were applied.
DDT Treatments for Control of Mole-Crickets
Experiment 4.-In a randomized series of 5 replications in 10
square foot plots, 2 methods of application based on the actual
amount of DDT per acre are compared in Table 5. The same
plot technique was used as in Experiment 3. The figures in
Table 5 are based on the average total lineal feet of runs per
day for 5 successive periods. The totals are the sum of the 5
replications.
Because of the failure of the DDT wettable powders in Ex-
periment 3, these were omitted in this test. It was decided to
test nearly comparable levels of actual DDT applied, using the
consistently performing emulsifiable oil materials against the
powders mixed with the fertilizer. In the first 3 tests it had
been noted that the different methods of application and dif-
ferent materials gave control at different time intervals fol-
lowing their application. In this fourth test, these have been
kept separately.
With a least significant difference of 28 feet of run in the
3-day period following treatment, equivalent control was secured
from all emulsifiable oil treatments and from the highest quan-
tity of DDT applied with the fertilizer (100 pounds actual DDT
per acre).
During the succeeding 5-day period, with a least significant
difference of 16 feet of run, similar results were secured but 1
of the oil treatments fell out of line slightly. During this period
all of the DDT treatments were giving some control, whereas
the 5 and 10 pound treatments mixed with the fertilizer were
ineffective during the first 3 days.
In the next 6-day period the 5 pounds of DDT per acre treat-
ment was numerically inferior to the 43.5 pounds but not signifi-
cantly so in the emulsifiable oil treatments. All of the DDT
plus fertilizer treatments afforded control with best results in
favor of the higher amounts.
The last 2 periods of 6 days and 3 days each show the 5 pounds
of DDT in the emulsifiable oil treatments losing their effective-
ness when compared with the 43.5 pounds of DDT. The 5 pounds
of DDT plus fertilizer had lost its effectiveness and had even
more burrowing than the check.
It may be seen from Table 5. that the emulsifiable oil treat-
ments were generally quicker working than were the treatments
wherein the DDT was applied with the fertilizer. It is also
evident that the degree of control secured was roughly correlated
with the amount of DDT applied and that the actual protection
TABLE 5.-A COMPARISON OF 2 METHODS OF DDT APPLICATION BASED ON POUNDS OF DDT PER ACRE.
Treatments
DDT 25% emulsion
DDT 25% emulsion
DDT 25% emulsion
DDT 25% emulsion
DDT 25% emulsion
DDT 50% powder
DDT 50% powder
DDT 50% powder
DDT 50% powder
DDT 50% powder
Check-no
treatment .........
Actual
Pounds
DDT
per
Acre
87.1
43.5
21.8
10
5
100
50
25
10
5
Fertilizer
only
Least significant
difference at odds 19:1
Dosage
1 gal. to 100 gals. water .................................
1/2 gal. to 100 gals: water ..................................
1 qt. to 100 gals. water ............... .......................
141/ oz. to 100 gals. water .....-...................
714 oz. to 100 gals. water ..............................
200 lbs. of 50% DDT mixed with fertilizer ..
100 lbs. of 50% DDT mixed with fertilizer ..
50 lbs. of 50% DDT mixed with fertilizer ....
20 lbs. of 50% DDT mixed with fertilizer ....
10 lbs. of 50% DDT mixed with fertilizer ...
Average Total Lineal Feet of Run
"o
5
5
60
57
95
94
103
28
28
35
O"C
11
18
35
21
25
20
35
40
50
63
81
16
to
13
20
41
21
38
26
40
41
60
52
82
21
t12 4-1
CD CO'U
4-> 0U
XC>M
4Z a)
23
34 R
49
35
70
25
44
45
51
74
69
91 Cr
23 r
34 ??
49 S
70
25 E
44
45
51 3.
74
69
9K
All material supplied by Du Pont.
All emulsions were applied at rate of 1 gal. per 10 sq. ft.
DDT Treatments for Control of Mole-Crickets
secured at the lower levels decreased with time as the experi-
ment progressed. It is of interest to note that as little as 5
pounds per acre of DDT gave measurable mole-cricket control,
although the beneficial effect of this small application disap-
peared within 20 days of its application regardless of source.
Effects on Germination
Three series of germination tests have been completed and
the results are given in Table 6. The seedlings were grown in
steam sterilized soil in uniform flats of 1 square foot in area.
These flats were in a screened greenhouse. A randomized series
of 5 replications was used throughout. All seedlings received
approximately the same amount of water. One seeding of let-
tuce was lost through failure of the seed to germinate and 2
seedings of pepper were destroyed by mice.
It will be noted in Table 6 that several of these tests showed
significant effects from DDT on the germination of certain seeds.
Generally, a slight decrease in germination was noted, but in a
few cases slight but significant increases resulted. It is felt
that these results indicate that the levels and treatments of
DDT used may be ignored insofar as the germination effects
are concerned, since the effects were generally of slight im-
portance.
Effects of Storage of DDT and Fertilizer on the
Germination of Tomato Seedlings
Fertilizer and DDT of different concentrations were mixed and
used over a period of 30 days to note the effect of storage to-
gether of these 2 materials and its resulting effect upon germina-
tion. One hundred tomato seeds were sown in treated soil,
germination was recorded and the container was discarded.
This meant new soil and a new container each day. The fer-
tilizer was used from the stock mixture made up. Results are
given in Table 7.
Slight reductions in germination were recorded for all treat-
ments at the end of 30 days. Even so, it could be considered
safe to use a mixture for at least 30 days so far as tomatoes are
concerned. No other seedlings have been tested.
Summary and Recommendations
In 4 separate experiments, each consisting of replicated and
randomized plots, DDT and other materials were tested as soil
applications for the control of mole-crickets in seedbeds.
DDT Treatments for Control of Mole-Crickets
secured at the lower levels decreased with time as the experi-
ment progressed. It is of interest to note that as little as 5
pounds per acre of DDT gave measurable mole-cricket control,
although the beneficial effect of this small application disap-
peared within 20 days of its application regardless of source.
Effects on Germination
Three series of germination tests have been completed and
the results are given in Table 6. The seedlings were grown in
steam sterilized soil in uniform flats of 1 square foot in area.
These flats were in a screened greenhouse. A randomized series
of 5 replications was used throughout. All seedlings received
approximately the same amount of water. One seeding of let-
tuce was lost through failure of the seed to germinate and 2
seedings of pepper were destroyed by mice.
It will be noted in Table 6 that several of these tests showed
significant effects from DDT on the germination of certain seeds.
Generally, a slight decrease in germination was noted, but in a
few cases slight but significant increases resulted. It is felt
that these results indicate that the levels and treatments of
DDT used may be ignored insofar as the germination effects
are concerned, since the effects were generally of slight im-
portance.
Effects of Storage of DDT and Fertilizer on the
Germination of Tomato Seedlings
Fertilizer and DDT of different concentrations were mixed and
used over a period of 30 days to note the effect of storage to-
gether of these 2 materials and its resulting effect upon germina-
tion. One hundred tomato seeds were sown in treated soil,
germination was recorded and the container was discarded.
This meant new soil and a new container each day. The fer-
tilizer was used from the stock mixture made up. Results are
given in Table 7.
Slight reductions in germination were recorded for all treat-
ments at the end of 30 days. Even so, it could be considered
safe to use a mixture for at least 30 days so far as tomatoes are
concerned. No other seedlings have been tested.
Summary and Recommendations
In 4 separate experiments, each consisting of replicated and
randomized plots, DDT and other materials were tested as soil
applications for the control of mole-crickets in seedbeds.
DDT Treatments for Control of Mole-Crickets
secured at the lower levels decreased with time as the experi-
ment progressed. It is of interest to note that as little as 5
pounds per acre of DDT gave measurable mole-cricket control,
although the beneficial effect of this small application disap-
peared within 20 days of its application regardless of source.
Effects on Germination
Three series of germination tests have been completed and
the results are given in Table 6. The seedlings were grown in
steam sterilized soil in uniform flats of 1 square foot in area.
These flats were in a screened greenhouse. A randomized series
of 5 replications was used throughout. All seedlings received
approximately the same amount of water. One seeding of let-
tuce was lost through failure of the seed to germinate and 2
seedings of pepper were destroyed by mice.
It will be noted in Table 6 that several of these tests showed
significant effects from DDT on the germination of certain seeds.
Generally, a slight decrease in germination was noted, but in a
few cases slight but significant increases resulted. It is felt
that these results indicate that the levels and treatments of
DDT used may be ignored insofar as the germination effects
are concerned, since the effects were generally of slight im-
portance.
Effects of Storage of DDT and Fertilizer on the
Germination of Tomato Seedlings
Fertilizer and DDT of different concentrations were mixed and
used over a period of 30 days to note the effect of storage to-
gether of these 2 materials and its resulting effect upon germina-
tion. One hundred tomato seeds were sown in treated soil,
germination was recorded and the container was discarded.
This meant new soil and a new container each day. The fer-
tilizer was used from the stock mixture made up. Results are
given in Table 7.
Slight reductions in germination were recorded for all treat-
ments at the end of 30 days. Even so, it could be considered
safe to use a mixture for at least 30 days so far as tomatoes are
concerned. No other seedlings have been tested.
Summary and Recommendations
In 4 separate experiments, each consisting of replicated and
randomized plots, DDT and other materials were tested as soil
applications for the control of mole-crickets in seedbeds.
TABLE 6.-EFFECT OF SOIL INSECTICIDES.UPON THE GERMINATION OF VEGETABLE SEEDLINGS. EACH VERTICAL SERIES OF
FIGURES REPRESENTS A SEPARATE EXPERIMENT.
Percentage Germination
Treatments* (Mean Number of Seedlings Emerged from 5 Replications)
_Cabbage I Tomatoes ILettuce**l Collards I Eggplant Pepperst
1. Benzene hexachloride 50%-2 lbs. to
100 gals. water .................................. 67.0 58.8 58.4 77.0 72.0 61.6 62.4 66.8 67.0 48.8 95.6 39.4 44.0 54.4 65.4
2. Benzene hexachloride 50%-1 lb. to
100 gals. water .................................. 76.4 61.8 49.2 89.6 72.2 61.6 74.6 60.0 85.0 53.0 91.8 63.2 47.0 51.2 69.6
3. DDT 50%-2 lbs. to 100 gals. water .... 68.6 64.4 54.6 79.4 74.6 65.4 87.4 63.8 78.2 59.0 80.8 58.8 48.5 47.4 69.2
4. DDT 50%-1 lb. to 100 gals. water ...... 69.0 60.6 59.2 78.4 60.8 58.0 84.8 55.0 77.2 54.2 91.6 67.8 35.5 50.4 73.0
5. DDT 25% emulsifiable oil-y2 gal. to
100 gals. water ........................ 65.8 67.2 51.4 72.4 75.4 67.6 76.8 62.6 70.2 55.2 94.2 73.4 46.5 54.4 72.8
6. DDT 25% emulsifiable oil-1 gal. to
100 gals. water .................................. 66.0 59.2 50.8 78.6 73.4 69.8 78.8 75.6 67.8 46.0 91.4 59.0 44.5 51.4 65.2
7. DDT 25% emulsifiable oil-y2 gal. to
100 gals. water ................................... 55.2 73.8 55.8 54.8 64.6 59.4 81.6 75.6 78.2 50.0 94.2 49.6 49.3 57.6 73.6
8. DDT 25% emulsifiable oil-1 gal. to
100 gals. water .................................... 56.2 65.0 53.4 65.4 69.6 60.8 70.4 49.6 70.4 46.6 84.4 48.6 48.3 54.2 49.2
9. Rhothane 25-1 gal. to 100 gals. water 72.2 67.8 57.0 71.0 68.4 68.4 84.2 74.2 69.0 55.2 87.2 52.0 46.3 56.4 66.8
10. Check ........................... ... ........ ............... 74.4 67.8 54.4 66.2 75.6 72.4 77.4 62.0 72.2 60.2 91.3 42.2 44.5 58.4 68.6
Totals must differ by (odds at 19:1) .......... 10.5 N.S.1N.S. N.S. 13.6 N.S. 13.9 N.S. N.S. N.S. N.S. 15.6 N.S. N.S. 3.36
Treatments 1 and 2 furnished by Niagara; 3 and 4 Deenate 5OW Dunont; 5 and 6, Gesarol E 25 by Geigy; 7 and 8 Deenate 25R by Dupont, and
9 Rhothane 25 by Rohm & Haas.
** The third lot of lettuce failed to germinate.
t Two lots of pepper were destroyed by mice.
$ N.S. means that upon statistical analysis it was found that no significance could be attached to differences in the test.
DDT Treatments for Control of Mole-Crickets
TABLE 7.-EFFECT OF STORAGE OF DDT AND FERTILIZER ON THE
GERMINATION OF TOMATO SEEDLINGS, 1945.
Actual Average Germination of 3 Replications
Actual -- -- -- -- -
Treatment DDT C32 3 C, g Cd CS -
per 4) ,
_Acre _a ___1 Acre a
1. 50 lbs. 20% DDT + fert. 10 85.0 83.6 82.1 80.7 79.7 82.0
2. 100 lbs. 20% DDT + fert. 20 84.7 86.4 79.2 86.4 79.9 83.0
3. 150 lbs. 20% DDT + fert. 30 87.5 87.1 82.1 86.9 79.7 84.3
4. 200 lbs. 20% DDT + fert. 40 84.7 86.2 80.3 84.1 78.5 82.4
5. Check-fertilizer only .... 82.8 83.7 81.9 85.9 81.2 83.0
Three forms of DDT were used, all of which are available
commercially. These were: (1) 25 percent DDT in emulsifiable
oil; (2) a 20 percent dust composed of DDT and an inert diluent;
and (3) a 50 percent wettable powder made up for use as a
spray material.
Other materials used were benzene hexachloride and rhothane.
Both of these reduced damage caused by mole-crickets in the
single experiment in which they were tested, but since neither
appeared to be superior to DDT and since other phases of their
use have not been investigated they cannot be recommended
as yet.
Two of the DDT formulations (the emulsifiable oil and the 20
percent dust) gave consistent control of mole-crickets at rates
low enough to make their use practical. As little as 5 pounds
per acre of actual DDT gave measurable control, although larger
quantities generally gave better control over longer periods of
time.
At the rates tested DDT had no important effect on the ger-
mination of cabbage, tomato, lettuce, collard, eggplant or pepper
seed. In a few cases some reduction in germination was found;
in others a slight stimulation occurred. It is safe to use a fer-
tilizer and DDT combination for at least 30 days after it has
been mixed.
In view of the results of the tests it is obvious that the form
of DDT used and the quantity required for suitable control are
dependent on (1) the population of mole-crickets, (2) the length
of time effective control is required and (3) the size of the area
to be protected. The recommendations which follow are based
on the assumption that at least 3 weeks' protection is desirable
and that mole-cricket populations are high.
Florida Agricultural Experiment Station
1. For Small Seedbed Areas.-The 25 percent DDT in emulsi-
fiable oil is recommended for use where it is possible to make
the application with a sprinkling can. One pint of the concen-
trate is diluted with 100 gallons of water. One gallon of this
mixture is applied to 10 square feet of soil with a sprinkling can.
It is desirable to go over the soil twice to be sure that a uniform
application is secured, sprinkling both lengthwise and crosswise
of the bed. The bed may be seeded within 2 or 3 days, or as
soon as the mole-crickets cease to be a nuisance. DDT applica-
tions stimulated mole-cricket activity for a day or 2, which is
an indication that the poison is taking effect. This treatment
gives 10 pounds of DDT per acre. The amount of DDT concen-
trate may be increased up to 1/2 gallon to 100 gallons of water
without causing injury to seedlings. This amount would give
43.5 pounds DDT per acre.
2. For Large Seedbed Areas.-The DDT dust is mixed with
the seedbed fertilizer, thus saving a separate operation. It is
recommended that 150 pounds of the 20 percent dust be mixed
with the quantity of fertilizer to be applied to an acre of seed-
bed area. This mixture is applied in the normal manner, being
carefully worked into the upper few inches of the soil. As in-
dicated above, the seed may be planted as soon as mole-cricket
activity decreases to the point where damage would be slight.
This treatment gives 30 pounds of DDT per acre; should the
population of mole-crickets be very heavy, the quantity of DDT
may be increased somewhat.
The above quantities of DDT have proven entirely safe with
the types of crops listed above which are commonly started in
seedbeds in Florida. The decreasing effectiveness of DDT as
a mole-cricket control with time would seem to indicate that this
material definitely deteriorates rather rapidly in the sandy soils
on which these tests were conducted.
Tests conducted elsewhere have indicated that DDT does not
break down rapidly in some soils, and considerable concern is
still felt as to the possible cumulative effects of DDT in the soil.
Continued experimentation will be required to establish this
point in Florida soils. Until definite proof is obtained, soil ap-
plications should be kept as low as possible in order to avoid a
toxic effect on plant life.
The quantities recommended above are certainly safe with
the crops listed in areas where seedbed locations are shifted from
year to year. In permanently located seedbed areas the mini-
DDT Treatments for Control of Mole-Crickets
mum quantity necessary for control should be used until more
is known of the cumulative effect.
In the above connection, pot tests have shown that plants
severely stunted by heavy applications of DDT (500 pounds per
acre and over) recovered when set into soil free of DDT. This
would seem to provide an added safety factor to the use of DDT
as a mole-cricket control in seedbeds. It cannot be recommended
for wide-scale field use where crops are to be grown to maturity
until more is known of its possible cumulative effect.
A good control of ants and cutworms may be expected from
the use of DDT applied by both methods.
Literature Cited
1. HAYSLIP, N. C. Notes on biological studies of mole-crickets at Plant
City, Fla. The Florida Entomologist 26: 3: 33-46. 1943.
2. KELSHEIMER, E. G. Naphthalene flakes keep mole-crickets from seed-
beds. Fla. Agr. Exp. Sta. Press Bul. 611. 1945.
3. WISECUP, C. B., and HAYSLIP, N. C. Control of mole-crickets by use of
poisoned baits. U.S.D.A. Leaflet 237. 1943.
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