• TABLE OF CONTENTS
HIDE
 Historic note
 Title Page
 Personnel
 Table 1
 Table of Contents
 Introduction
 Multiple application trials
 Single application trials
 Summary














Group Title: Bulletin - University of Florida. Agricultural Experiment Station ; no. 446
Title: Tests of new insecticides for the control of aphids on celery in the Everglades
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00026402/00001
 Material Information
Title: Tests of new insecticides for the control of aphids on celery in the Everglades
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 28 p. : ; 23 cm.
Language: English
Creator: Wylie, W. D ( William Dickey ), 1914-
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1948
 Subjects
Subject: Celery -- Diseases and pests -- Control -- Florida -- Everglades   ( lcsh )
Aphids -- Control -- Florida -- Everglades   ( lcsh )
Insecticides -- Florida -- Everglades   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: by W.D. Wylie.
General Note: Cover title.
Funding: Bulletin (University of Florida. Agricultural Experiment Station)
 Record Information
Bibliographic ID: UF00026402
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000925524
oclc - 18254135
notis - AEN6175

Table of Contents
    Historic note
        Historic note
    Title Page
        Page 1
    Personnel
        Page 2
        Page 3
    Table 1
        Page 4
    Table of Contents
        Page 5
    Introduction
        Page 5
    Multiple application trials
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
    Single application trials
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
        Page 26
    Summary
        Page 27
        Page 28
Full Text





HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida






August, 1948


UNIVERSITY OF FLORIDA
AGRIULTURAL EXPERIMENT STATION
HAROLD MOWRY, Director
GAINESVILLE, FLORIDA







Tests of New Insecticides for the


Control of Aphids on Celery


in the Everglades


By W. D. WYLIE













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


Bulletin 446









BOARD OF CONTROL

J. Thos. Gurney, Chairman, Orlando
N. B. Jordan, Quincy
Thos. W. Bryant, Lakeland
J. Henson Markham, Jacksonville
Hollis Rinehart, Miami
W. F. Powers, Secretary, Tallahassee


EXECUTIVE STAFF
J. Hillis Miller, Ph.D., President of the
University3
H. Harold Hume, D.Sc., Provost for Agr.'
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., Editor3
Clyde Beale, A.B.J., Associate Editor3
Ida Keeling Cresap, Librarian
Ruby Newhall, Administrative Manager3
Geo. F. Baughman, M.A., Business Manager3
Claranelle Alderman, Accountant3


MAIN STATION, GAINESVILLE

AGRICULTURAL ENGINEERING
Frazier Rogers, M.S.A., Agr. Engineer3
J. M. Johnson, B.S.A.E., Asso. Agr. Engineer3
J. M. Myers, B.S., Asso. Agr. Engineer
R. E. Choate, B.S.A.E., Asst. Agr. Engineer3
A. M. Pettis, B.S.A.E., Asst. Agr. Engineer2s

AGRONOMY
Fred H. Hull, Ph.D., Agronomist
G. E. Ritchey, M.S., Agronomist2
G. B. Killinger, Ph.D., Agronomist'
H. C. Harris, Ph.D., Agronomists
R. W. Bledsoe, Ph.D., Agronomist
M. E. Paddick, Ph.D., Agronomist
S. C. Litzenberger, Ph.D., Associate
W. A. Carver, Ph.D., Associate
Fred A. Clark, B.S., Assistant

ANIMAL INDUSTRY
A. L. Shealy, D.V.M., An. Industrialist' 3
R. B. Becker, Ph.D., Dairy Husbandman'
E. L. Fouts, Ph.D., Dairy Technologist3
D. A. Sanders, D.V.M., Veterinarian
M. W. Emmel, D.V.M. Veterinarian3
L. E. Swanson, D.V.M., Parasitologist
N. R. Mehrhof, M.Agr., Poultry Husb.3
G. K. Davis, Ph.D., Animal Nutritionist3
R. S. Glasscock, Ph.D., An. Husbandman'
P. T. Dix Arnold, M.S.A., Asst. Dairy Hush.'
C. L. Comar, Ph.D., Asso. Biochemist
L. E. Mull, M.S., Asst. in Dairy Tech.
Katherine Boney, B.S., Asst. Chem.
J. C. Driggers, B.S.A., Asst. Poultry Husb.3
Glenn Van Ness, D.V.M., Asso. Poultry
Pathologist
S. John Folks, B.S.A., Asst. An. Husb.3
W. A. Krienke, M.S., Asso. in Dairy Mfs.3
S. P. Marshall, Ph.D., Asso. Dairy Husb.3
C. P. Simpson, D.V.M., Asso. Veterinarian
C. F. Winchester, Ph.D., Asso. Biochemist3


ECONOMICS, AGRICULTURAL
C. V. Noble, Ph.D., Agri. Economist1 3
Zach Savage, M.S.A., Associate
A. H. Spurlock, M.S.A., Associate
D. E. Alleger, M.S., Associate
D. L. Brooke, M.S.A., Associate
R. E. L. Greene, Ph.D., Agri. Economist
H. W. Little, M.S., Assistant

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
J. F. Steffens, Jr., B.S.A., Agr. Statistician2

ECONOMICS, HOME
Ouida D. Abbott, Ph.D., Home Econ.'
R. B. French, Ph.D., Biochemist

ENTOMOLOGY
A. N. Tissot, Ph.D.. Entomologist'
L. C. Kuitert, Ph.D., Assistant
H. E. Bratley, M.S.A., Assistant

HORTICULTURE
G. H. Blackmon, M.S.A., Horticulturist'
F. S. Jamison, Ph.D., Horticulturist3
H. M. Reed, B.S., Chem., Veg. Processing
Byron E. Janes, Ph.D., Asso. Hort.
R. A. Dennison, Ph.D., Asso. Hort.
R. K. Showalter, M.S., Asso. Hort.
Albert P. Lorz, Ph.D., Asso. Hort.
R. H. Sharpe, 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.4
F. S. Lagasse, Ph.D., Asso. Hort.2
L. H. Halsey, B.S.A., Asst. Hort.

PLANT PATHOLOGY
W. B. Tisdale, Ph.D., Plant Pathologist13
Phares Decker, Ph.D., Asso. Plant Path.
Erdman West, M.S., Mycologist and Botanist
Howard N. Miller, Ph.D., Asso. Plant Path.
Lillian E. Arnold, M.S., Asst. Botanist

SOILS
F. B. Smith, Ph.D., Microbiologist' 3
Gaylord M. Volk, Ph.D., Chemist
J. R. Henderson, M.S.A., Soil Technologist3
J. R. Neller, Ph.D., Soils Chemist
Nathan Gammon, Jr., Ph.D., Soils Chemist
C. E. Bell, Ph.D., Associate Chemist
R. A. Carrigan, Ph.D., Asso. Biochemist3
H. W. Winsor, B.S.A., Assistant Chemist
Geo. D. Thornton, Ph.D., Asso. Microbiologist'
R. E. Caldwell, M.S.A., Asst. Chemist3
J. B. Cromartie, B.S.A., Soil Surveyor
Ralph G. Leighty, B.S., Asso. Soil Surveyor
V. W. Cyzycki, B.S., Asst. Soil Surveyor
R. B. Forbes, M.S., Asst. Soils Chemist
W. L. Pritchett, M.S., Asst. Chemist
Jean Beem, B.S.A., Asst. Soil Surveyor

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









BRANCH STATIONS

NORTH FLORIDA STATION, QUINCY
J. D. Warner, M.S., Vice-Director in Charge-
R. R. Kineaid, 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. Husb.
Kelvin Dorward, M.S., Entomologist

Mobile Unit, MontieelTo
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

Mo'ile 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
B. F. Suit, Ph.D., Plant Pathologist
E. P. Ducharme, M.S., Plant Pathologist4
R. K. Voorhees, M.S., Asso. Horticulturist
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. Granger, B.S.A., Asst. Horticulturist
H. J. Reitz, M.S., Asso. Horticulturist
Francine Fisher, M.S., Asst. Plant Path.
I. W. Wander, Ph.D., Soils Chemist
A. E, Willson, B.S.A., Asso. Biochemist
J. W. Kesterson, M.S., Asso. Chemist
R. N. Hendrickson, B.S., Asst. Chemist
E. H. Bitcover, M.A., Soils Chemist
L. C. Knorr, Ph.D., Asso. Histologist
Joe P. Barnett, B.S.A., Asst. Horticulturist
J. C. Bowers, B.S., Asst. Chemist
D. S. Prosser, Jr., B.S., Asst. Horticulturist
R. W. Olsen, B.S., Biochemist
F. W. Wenzel, Jr., Ph.D., Supervisory Chem.

EVERGLADES STATION, BELLE GLADE
R. V. Allison, Ph.D., Vice-Director in Charge
F. D. Stevens, B.S., Sugarcane Agronomist
Thomas Bregger, Ph.D., Sugarcane
Physiologist
J. W. Randolph, M.S., Agricultural Engineer
W. T. Fbrsee, Jr., Ph.D., Chemist
R. W. Kidder, M.S., Asso. Animal Husb.
T. C. Erwin, Assistant Chemist
Roy A. Bair, Ph.D., Agronomist
C. C. Seale, Asso. Agronomist
N. C. Hayslip, B.S.A., Asso. Entomologist
E. H. Wolf, Ph.D., Asst. Horticulturist
W. H. Thames, M.S., Asst. Entomologist
J. C. Hoffman, M.S., Asso. Horticulturist


C. B. Savage, M.S.A., Asst. Horticulturist
D. L. Stoddard, Ph.D., Asso. Plant Path.
W. A. Desnoyers, B.S., Asst..i hydrologist

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
Robt. A. Conover, Ph.D., Asso. Plant Path.
R. W. Harkness, Ph.D., Asst. Chemist
Milton Cobin, B.S., Asso. Horticulturist


W. CENT. FLA. STATION, BROOKSVILLE

William Jackson, B.S.A., Animal Husband-
man in Charge2

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 Technologist
H. J. Ful'ord, B.S.A. Asst. Animal Husb.

CENTRAL FLORIDA STATION, SANFORD

R. W. Ruprecht, Ph.D., Vice-Dir. in Charge
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., Associate 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
A. M. Phillips, B.S., Asso. Entomologist2

Bradenton
J. R. Beckenbach, Ph.D., Hort. in Charge
E. G. Kelsheimer, Ph.D., Entomologist
David G. Kelbert, Asso. Horticulturist
E. L. Spencer, Ph.D., Soils Chemist
Robert O. Magie, Ph.D., Gladioli Hort.
J. M. Walter, Ph.D., Plant Pathologist
Donald S. Burgis, M.S.A., Asst. Hort.

Lakeland
Warren O. Johnson, B.S., Meteorologist2

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














TABLE 1.-EFFECTS OF WEEKLY APPLICATIONS OF VARIOUS INSECTICIDE-
FUNGICIDE COMBINATIONS ON CELERY APHIDS IN THE SPRING OF 1946.


Amount Total Number Aphids
Insecti- |
Spray Material* cide Per 30 Per 60 Trifoliate Leaves
per 100 Plants March March April April
Gallons Feb. 25 12 19 2 22

DDT 50% wettable1
+ dithane-zinc-
lime 2 ........................ 2 Ib. 141 3,179 13 397 3,057

DDT 50% wettable +
zerlate ................... 2 lb. 270 2,984 18 565 2,107

Pyrethrum extract + 1 pt.
Rotenone extract6 + 1 pt.
Bordeaux ................ 139 1,103 833 89 1,050

Pyrethrum extract + 1 pt.
Rotenone extract + 1 pt.
Dithane D-14 .............. 122 382 196 39 103

Nicotine sulfate +
bordeaux .................. 1 pt. 42 163 423 34 98

Nicotine sulfate +
zerlate ........----..... 1 pt. 84 133 149 17 10

Check (no spray) ...... 83 96 36 22 30

Total .................... 881 8,040 1,668 1,163 6,455

Least sig. diff. (19:1) -- ........ ...... 785 465 151 --

'F' required (19:1) .................... 2.15 2.51 2.15 2.51 3.00

'F' obtained (19:1) .................... 1.05 25.60 2.64 18.27 2.48
*Applied January 29, February 5, 12, 19, 27, March 5, 12, 20, 29, April 2, 9, 16.
1 DDT (Dichloro-diphenyl-trichloroethane).
2Dithane D-14 (disodium-ethylene-bisdithio-carbamate) 2 qt., zinc sulfate 1 lb., hydrated
lime 1/ lb.
3 Zerlate (zinc dimethyl-dithiocarbamate) 2 lb.
4 1% pyrethrins.
5 3.4% rotenone, 6.8%-other cube resins.
Bordeaux-copper sulfate 8 lb., hydrated lime 4 lb., wettable sulfur 4 lb.









Tests of New Insecticides for the Control

of Aphids on Celery in the Everglades

W. D. WYLIE

CONTENTS
Page
Introduction .............. ......... .................... ................. 5
Multiple Application Trials ................................. ................ 5
Single Application Trials .......... ........................................ 15
Sum m ary ............................ ...... .......... ........ .................... 27

INTRODUCTION

Celery is an important crop in the Everglades of Florida, sev-
eral thousand acres being grown each year. Aphids are one of
the principal insect pests. They are largely responsible for the
spread of mosaic, which sometimes causes severe celery losses. In
addition, the aphids may become sufficiently abundant to cause
considerable direct injury. Use of insecticides usually prevented
injury. However, the kill of aphids has not been sufficient to
prevent reinfestation. A light infestation may cause many
plants to become infected with mosaic.
Experiments were conducted in an endeavor to find a more
satisfactory aphicide for celery than those available in the past.
The dosage, number and frequency of applications, and com-
patibility with fungicides also were considered. Three seasonal
tests were conducted in the spring and fall of 1946 and the spring
of 1947. Five experiments of single applications to small plots
in commercial fields were conducted from November, 1946, to
April, 1947. The three multiple application experiments were
conducted on the grounds of the Everglades Experiment Station,
Belle Glade, Florida. The other tests were conducted in the
vicinity of Belle Glade. The species of aphid encountered in
most of the tests was Aphis gossypii Glov.2

MULTIPLE APPLICATION TRIALS
In the spring of 1946 an insecticide experiment was set up
in conjunction with some fungicide tests. Nicotine sulfate,

1Former Entomologist, Everglades Experiment Station, Belle Glade,
Florida.
2 Dr. A. N. Tissot, Agricultural Experiment Station, Gainesville, Florida,
made all the determinations of the species of aphids involved. He also
kindly read and criticized this paper before publication.









Tests of New Insecticides for the Control

of Aphids on Celery in the Everglades

W. D. WYLIE

CONTENTS
Page
Introduction .............. ......... .................... ................. 5
Multiple Application Trials ................................. ................ 5
Single Application Trials .......... ........................................ 15
Sum m ary ............................ ...... .......... ........ .................... 27

INTRODUCTION

Celery is an important crop in the Everglades of Florida, sev-
eral thousand acres being grown each year. Aphids are one of
the principal insect pests. They are largely responsible for the
spread of mosaic, which sometimes causes severe celery losses. In
addition, the aphids may become sufficiently abundant to cause
considerable direct injury. Use of insecticides usually prevented
injury. However, the kill of aphids has not been sufficient to
prevent reinfestation. A light infestation may cause many
plants to become infected with mosaic.
Experiments were conducted in an endeavor to find a more
satisfactory aphicide for celery than those available in the past.
The dosage, number and frequency of applications, and com-
patibility with fungicides also were considered. Three seasonal
tests were conducted in the spring and fall of 1946 and the spring
of 1947. Five experiments of single applications to small plots
in commercial fields were conducted from November, 1946, to
April, 1947. The three multiple application experiments were
conducted on the grounds of the Everglades Experiment Station,
Belle Glade, Florida. The other tests were conducted in the
vicinity of Belle Glade. The species of aphid encountered in
most of the tests was Aphis gossypii Glov.2

MULTIPLE APPLICATION TRIALS
In the spring of 1946 an insecticide experiment was set up
in conjunction with some fungicide tests. Nicotine sulfate,

1Former Entomologist, Everglades Experiment Station, Belle Glade,
Florida.
2 Dr. A. N. Tissot, Agricultural Experiment Station, Gainesville, Florida,
made all the determinations of the species of aphids involved. He also
kindly read and criticized this paper before publication.









Tests of New Insecticides for the Control

of Aphids on Celery in the Everglades

W. D. WYLIE

CONTENTS
Page
Introduction .............. ......... .................... ................. 5
Multiple Application Trials ................................. ................ 5
Single Application Trials .......... ........................................ 15
Sum m ary ............................ ...... .......... ........ .................... 27

INTRODUCTION

Celery is an important crop in the Everglades of Florida, sev-
eral thousand acres being grown each year. Aphids are one of
the principal insect pests. They are largely responsible for the
spread of mosaic, which sometimes causes severe celery losses. In
addition, the aphids may become sufficiently abundant to cause
considerable direct injury. Use of insecticides usually prevented
injury. However, the kill of aphids has not been sufficient to
prevent reinfestation. A light infestation may cause many
plants to become infected with mosaic.
Experiments were conducted in an endeavor to find a more
satisfactory aphicide for celery than those available in the past.
The dosage, number and frequency of applications, and com-
patibility with fungicides also were considered. Three seasonal
tests were conducted in the spring and fall of 1946 and the spring
of 1947. Five experiments of single applications to small plots
in commercial fields were conducted from November, 1946, to
April, 1947. The three multiple application experiments were
conducted on the grounds of the Everglades Experiment Station,
Belle Glade, Florida. The other tests were conducted in the
vicinity of Belle Glade. The species of aphid encountered in
most of the tests was Aphis gossypii Glov.2

MULTIPLE APPLICATION TRIALS
In the spring of 1946 an insecticide experiment was set up
in conjunction with some fungicide tests. Nicotine sulfate,

1Former Entomologist, Everglades Experiment Station, Belle Glade,
Florida.
2 Dr. A. N. Tissot, Agricultural Experiment Station, Gainesville, Florida,
made all the determinations of the species of aphids involved. He also
kindly read and criticized this paper before publication.






Florida Agricultural Experiment Station


wettable DDT and rotenolie-piyretliriin were used with'two dif-
ferent fungicides. The celery was set in the field January 15 to
19, 1946. Cultural practices were those normally used in grow-
ing this crop in the Everglades. Each plot consisted of six
rows 200 feet in length, and each treatment was replicated five
times. Sprays were applied with a power sprayer at 400 pounds
pressure, with four nozzles per row, using about 125 gallons of
spray per acre. Twelve applications were made at weekly in-
tervals beginning on January 29. The aphid population was
determined at various intervals by making counts. The numbers
were so low that the first three counts were made on several
entire plants in each plot. This method was impractical on the
older plants, hence the last four counts were made by selecting
trifoliate leaves from the top, middle and bottom of several
plants in each plot. The aphid population is normally much
larger on the lower leaves.
The insecticide-fungicide combinations used, as well as the
results of five of the aphid counts per treatment, are given in
Table 1. The first count is on the basis of the total number of
aphids on six entire plants, or a total of 30 entire plants per treat-
ment. The last four counts in Table 1 are on the basis of the
number of aphids on 12 trifoliate leaves per plot or a total of 60
such leaves per treatment. The final count on April 22 was
made on only three plots per treatment, since two plots of each
treatment were disked under prior to that date. In order to
make the figures for April 22 comparable with the three preced-
ing counts, they are adjusted to represent 60 leaves.
Although two applications of the insecticides had been made
prior to that time, it will be noted that there were no significant
differences between any of the treatments on February 25. By
March 12 the differences between treatments were highly sig-
nificant, with the plots receiving DDT having a higher popu-
lation than did those receiving nicotine, rotenone-pyrethrum, or
the check. The rotenone-pyrethrum plus bordeaux treatment
was significantly poorer than the remaining treatments, including
the check. Since DDT has been said to cause an increase in
populations of aphids due to destruction of parasites and preda-
tors, observations were made on that point. Ladybeetles and
hymenopterous parasites were always most abundant in the
DDT plots.
The counts on March 19 still showed significant differences
between treatments, although the relative position was changed.







Control of Aphids on Celery


While the aphid population was lower in all treatments except
those receiving nicotine, the reduction in the case of the DDT
treatments was much greater. On March 15 to 16 there was a
total rainfall of 5.40 inches. Possibly the DDT spraying had
some effect on the aphids that caused them to be more susceptible
to the heavy rains. Or possibly the rains were instrumental in
causing the DDT to be more effective, which seems highly im-
probable.
Although the insecticides continued to be applied at weekly
intervals, this did not prevent the populations on the DDT plots
from building up again. By April 22 the aphid population on
the DDT plots had again reached about the same level as on
March 12. However, the differences between treatments were
not significant.
The data in Table 1 indicate that the fungicide used with an
insecticide may have some effect on the aphid population.
Dithane, when first on the market, was claimed to be instru-
mental in holding aphids in check if used regularly. In each
case as the aphid population began to develop on the DDT plots
it appeared that the plots receiving zerlate were building up
more rapidly than the dithane plots. However, the population
actually reached a higher ultimate level on the plots receiving
dithane. Also the low aphid population on the unsprayed plots
brings up a question of the effect of fungicides on the aphid
population.
In Table 2 aphid population counts on plots receiving fungicides
alone are given, along with these same fungicides combined
with insecticides. No statistically significant differences in
counts appeared between the fungicide and the check plots until
March 19. However, indications are that the aphid population
tended to be higher on the plots receiving no fungicides. In
the counts made on March 19 the bordeaux plots showed a sig-
nificantly higher aphid population than the check. This differ-
ence may have been due to the action of the fungicides in destroy-
ing entomogenous fungi. Although some evidence of the activity
of these fungi was seen, it did not appear to be of consequence.
Another possibility is that the fungicides affected the physiolog-
ical condition of either the plants or the aphids themselves.
The heavy rains of March 15 and 16, as mentioned above, in-
jured the celery to such an extent that it was not harvested.
Thus no harvest records or measurements of the incidence of
mosaic were obtained.







8 Florida Agricultural Experiment Station

Aphids collected on the celery in this experiment were identi-
fied as Aphis gossypii Glover.
Another celery insecticide experiment was laid out and the
plants set in the field on October 25, 1946. Cultural practices
generally employed in the area were observed. Each plot con-
sisted of four rows 25 feet in length. Each treatment was

TABLE 2.-EFFECT OF WEEKLY APPLICATIONS OF INSECTICIDE-FUNGICIDE
COMBINATIONS AND FUNGICIDES ALONE ON CELERY APHIDS IN THE
SPRING OF 1946.

Total Number Aphids
Amount
Spray Materials* per 100 Per 30 Plants Per 60 Tri-
Gallons foliate Leaves
Feb. Feb. March March
__12 25 6 19

DDT 50% wettable 2 lb.
+ dithane ............. 38 141 8,430 13
DDT 50% wettable 2 lb.
+ zerlate .............. 10 270 6,861 18
Pyrethrum extract 1 pt.
+ rotenone extract 1 pt.
+ bordeaux ............. 15 139 2,555 833
Bordeaux ............... 8-4-4 10 144 2,372 502
Zerlate ......-.............. 2 lb. 21 171 2,054 163
Pyrethrum extract
(1% pyrethrins) 1 pt.
Rotenone extract
(3.4% rotenone) 1 pt.
+ dithane ............... 11 122 1,882 196
Dithane D-14, zinc,
lime .......... .... 2-1-% 19 123 1,860 120
Check .......................... ...... 26 83 917 36
Nicotine sulfate + 1 pt.
zerlate ...................- 5 84 897 i49
Nicotine sulfate + 1 pt.
bordeaux ................. 11 42 770 423
.Total ................... 166 1,319 28,598 2,453

Least significant di. (19:1) ...... ..... 3,155 465
'F' obtained
(reqiLiir.1=2.15 @ 19:1) .... 1.51 1.05 5.66 2.64

Applied January 29, February 5, 12, 19, 27, March 5, 12, 20, 29, April 2, 9, 16







Control of Aphids on Celery


replicated four times. The insecticides were applied in com-
bination with the fungicide, using a small wheelbarrow sprayer
powered by a small air-cooled engine. The sprays were applied
at 200 pounds pressure employing a single nozzle, the amount
of spray being increased from 125 gallons per acre when the
plants were small to about 200 gallons on older plants. A total
of seven applications were made on the following dates: No-
vember 12, 19, 26; December 3, 17, 31; and January 7. In addi-
tion, all plots received an application of fungicide on December
11, 24; January 10, 14, 18 and 22. Some of the aphicides were
used at one-half the tentatively recommended dosage. Proposed
heavier dosages of these aphicides at bi-weekly intervals were
not applied due to the light infestation.
The first aphid count was made on December 5 after four
applications of insecticide. These data are presented in Table
3. As in the previous experiment, the DDT wettable material
showed a significantly higher aphid population than the other
insecticides or the check. In this experiment the aphid popu-
lation on the DDT plots never reached the level attained in the
spring; however, fewer applications of insecticide were made
in the fall. No opportunity was afforded in the fall experiment
to ,determine whether excessive rainfall would affect the aphid
population as it had in March. On December 14 a rainfall of
2.48 inches was recorded, but this was less than half the rainfall
for the two-day period in March.
A comparison of results with the DDT emulsion and the
wettable DDT indicates the former was more effective, though
the actual amount of DDT per acre was approximately twice as
great in the case of the wettable material. In the two instances
that the count for the emulsion was greater than for the wettable
powder the observations were made at a considerable interval
after the last application of spray.
A comparison of the counts for benzene hexachloride (33%)
at two pounds and DDT emulsion at one quart shows no sig-
nificant difference between them at any time.
It appeared that vapotone at one-half pint was equally as good
as nicotine sulfate at one pint with each of the fungicides used
in combination with it. It also appeared that neither of these
fungicides had any deleterious effects on the vapotone.
The chlordane and rhothane emulsions are not significantly
different from the check, except in the case of the higher count







TABLE 3.-EFFECTIVENESS OF VARIOUS APHICIDES IN CONTROLLING APHIDS ON CELERY IN THE FALL
AND WINTER OF 1946-1947.


Amount Total Number Aphids per 48 Trifoliate Leaves
Spray Material* Per 100 Dec. Dec. Dec. Dec. Jan. Jan. Jan.
Gallons 5 16 20 31 4 10 27

DDT 50% etettable ....................................... 2 lb. 579 1,110 913 334 524 279 48

DDT 25% emulsion ......................................1... qt. 24 239 169 406 72 48 154

Benzene hexachloride 33% wettable
(4% gamma isomer). ................................... 2 lb. 161 .541 409 242 39 40 131

Vapotonel ...................... ............................ pt. 35 67 44 116 42 6 18

Vapotone2 .................... ...................... ........ pt. 2 25 19 83 53 10 58

Nicotine sulfate ............................................. 1 pt. 2 20 17 119 23 10 23

Chlordane3 25% emulsion ............................. qt. 37 178 195 165 127 83 79

Rhothane4 25% emulsion ................................. 1 qt. 147 381 223 138 89 70 200

Check (fungicide alone) ............................... 173 151 178 300 132 63 48

Dendrox ...-...................... ...................... .. 1 qt. 74 216 129 203 46 16 110

Total ................. .................................... 1,234 2,928 2,296 2,106 1,147 625 869

Least significant difference (19:1) .................................... 294 437 285 206 146 77 101

'F' obtained (required = 2.25 @ 19:1) ............................. 2.89 4.77 7.36 2.28 8.61 9.20 2.95
Applied November 12, 19, 26, December 3, 17, 31, and January 7.
1Label showed: Active ingredients by wt. Tetraethyl phosphates 9%, other organic phosphate 41%, inert 50%.
2 Plus copper compound A 4 lb.-all other sprays contained H E 178E (dry Dithane) 22 pounds.
3 1,2,4,5,6,7,8,8-Octachloro-4, 7-methano-3a, 4,7,7a-tetrahydroindane.
4Dichloro diphenyl dichloroethane.
5 Lable showed: Active ingredients 1% mono and dimethylated naphtha'enes. State chemists analysis showed chlorine present equivalent to 29%
DDT or 27.5% benzene hexachloride.






Control of Aphids on Celery


for rhothane on January 27. Here the difference was small and
the count made 20 days after the last spray application.
As the celery approached maturity, early blight (Cercospora
apii Fres.) became severe in spite of frequent applications of
fungicide. This possibly was due to incomplete spraying of the
large plants with the wheelbarrow sprayer. The celery was
harvested on January 28. Yield records were taken, but the
uneven incidence of blight throughout the experiment masked
differences in yield that may have been due to the insecticides.
The heavy incidence of blight also made it difficult to determine
the amount of mosaic present. These data are presented in
Table 4.
Several observations were made as the celery approached
maturity to determine if the insecticides used were causing any
undesirable taste in the celery. The celery from plots receiving
benzene hexachloride definitely tasted of this material for a
period of at least one week following treatment. That from the
plot receiving DDT emulsion was said to have an oily taste by
one taster. At harvest time, which was three weeks after the
final application of insecticides, the writer failed to detect any
undesirable taste in the celery.

TABLE 4.-YIELD AND NUMBER OF STALKS DISCARDED BECAUSE OF MOSIAC
IN CELERY SPRAYED WITH DIFFERENT INSECTICIDES IN THE FALL OF 1946.

Amount Totals for 1/36 Acre
Spray Material per 100 Number Number
Gallons Boxes Stalks with
Celery Mosaic
Vapotone + copper A ..........- ... 1/ pt. 10.8 14
Rhothane 25% emulsion ..---........... 1 qt. 9.8 24
DDT 25% emulsion ...................... 1 qt. 9.5 23
Nicotine sulfate ............................ 1 pt. 9.5 15
Dendrox ................................ 1 qt. 8.7 14
Check (fungicide alone) ................ 8.6 20
Vapotone + dry dithane ......... 1/ pt. 8.6 14
Chlordane 25% emulsion ........... 1 qt. 8.6 5
DDT 50% wettable ........................ 2 lb. 8.3 17
Benzene hexachloride 33% wet-
table, 4% gamma isomer .......... 2 lb. 8.2 14







Florida Agricultural Experiment Station


On January 23, 1947, celery plants were set in the field for a
third experiment. A large power sprayer was used to apply the
fungicide. Insecticides were applied separately with the small
wheelbarrow sprayer. Each plot consisted of four rows 18 feet
in length. Each treatment was replicated five times in a ran-
domized block. Two experiments consisting of seven treatments,
each complete with a check, were set up side by side.
On February 5 a freeze severely injured the plants. On March
2 a 6.53-inch rainfall was recorded. Several additional heavy
rains occurred in March, with 1.77 inches recorded on the 16th
and 1.32 inches on the 20th. In view of these unfavorable con-
ditions, the aphid population remained low. The first spray
application was made on March 28 to part of the plots and a
second application on April 3. By April 11 the aphid population
was so low that the experiment was re-designed. The plants

TABLE 5.-APHID ABUNDANCE ON CELERY PLANTS RECEIVING DIFFERENT
SPAY TREATMENTS AS INDICATED BY COUNTS MADE ON ARIL 15.

Total No. Aphids per 12
Amt. Leaves
Spray Material* per
100 DDT 50% Average
Gals. Wettable Check Total
March 14
A B Av. A B Av. I

DDT 50% wettable .... 2 lb. 49 103 76 55 55 207 69
DDT 25% emulsion qt. 36 33 34 9 3 6 81 20
Benzene hexachloride
50% wettable (6%
gamma isomer) .... 4 lb. 37 63 50 ... 22 22 122 41
Toxaphene1
25% wettable ........ 4 lb. .... 13 13 15 5 10 33 11
DDT 50% wettable 2 lb.
Benzene hexachloride
50% wettable (6%
gamma isomer) ...... 2 lb. 75 ... 75 14 2 8 91 30
Check .............. .......... 47 110 78 9 14 11 180 45

Total ................ ....................... 566 148 714 36
Average ............... ............... 57 15 36

Applied April 11, 1947.
1A chlorinated bicyclic (CloHxoCls).





TABLE 6.-RELATIVE ABUNDANCE OF APHIDS ON CELERY PLANTS RECEIVING DIFFERENT SPRAY TREATMENTSr
AS INDICATED BY COUNTS MADE APRIL 22. (SPRAY APPLICATIONS APRIL 11 AND 18.)

SNo. Aphids per 12 Trifoliate Leaves


Spray Material


No. of
Appli-
cations


Amount
per
100 Gals.


DDT
50%
Wet-
table


Benzene
Hex. 2 lb.
DDT
Wettable


Check


Benezene
Hexa-
chloride
50%
Wettable


DDT
25%
Emulsion
1 quart


Toxaphene
25%
Wettable
4 lb.


Total


I Average
I


S_____2 lb. 2 lb. _4 lb. __
A. Toxaphene 50% emulsion 11 1 qt. 192 19 29 .... 48 .... 288 72
DDT 50% wettable 2 lb.
Benzene hexachloride
50% wettable ................ 1 2 lb. 20 15'0 150 ... 12 19 351 70
DDT 50% wettable ........ 1 2 lb. .... 150 83 30 41 26 330 66
Check ............................ 160 .... 40 46 -.. 18 264 66
DDT 25% emulsion 1 qt.
Benzene hexachloride
50% wettable ......... ....... 1 2 lb. 98 63 ... 21 73 14 269 54
DDT 34% emulsion........ 1 1 pts. 55 .... 19 12 .. 26 112 28
Benzene hexachloride
50% wettable ............... 1 4 lb. 5 13 .... 71 3 15 107 21
Total ................-...................-.... 530 395 321 180 177 118 1,721 54
Average ..................... --.. ............... 88 7) 64 36 35 20 54
B. DDT 50% wettable ...... 22 2 lb. 31 93 29 126 ..- 279 70
Check .................-- 32 7 12 .... 6 16 73 15
Nicotine sulfate ............. 1 1 pt. 28 64 2 .... 40 10
Toxaphene 25%
wettable ....................... 2 4 lb. ... 3 8 29 2 2 44 9
Vapotone ............... .. 2 1 pt. 14 .. 12 9 2 10 47 9
DDT 25% emulsion ........ 2 1 qt. 16 3 .... .. 4 5 28 7
Benzene hexachloride
50% wettable ............... 2 4 lb. 13 6 6 1 4 12 42 7
Total ............---..--. ...-.. .....---...... 134 1_8 42 68 146 45 553 21
Average ................... .. ......... ........... 22 20 8 17 21 9 21 _
Grand total ---........-. ... .. ...... 664 513 363 248 323 163 2,274 35
Grand average ........................ .......-.... .... 55 47 36 28 27 15 35
1 Applied April ,3.
2 Applied March 28 and April 3.






Florida Agricultural Experiment Station


were too la rge to use the small sprayer. The original plot ar-
rangement was abandoned and the plot size increased o six rows
36 feet in length. Applications of insecticides wer made on
April 11 and 18 u-ing the largi-e pIwer .-lpr : aye'r.
On March 14 some plants within the area of the eXperiment,
but outside of the small original plots, were sprayed with
wettable DDT two pounds per 100 gallons of water. These
plants were included in the new experimental layout and received
an application of the sprays applied on April 11 with the power
sprayer. Counts were made April 15 on these plants, as well
as on some that had received no insecticide prior to April 11.
These data are given in Table 5. Although no statistical analysis
was made, indications are that the application of wettable DDT
was instrumental in increasing the aphid population over that
occurring where no insecticide was applied.
In Table 6 the results of an aphid count made on April 22 are
given.
The celery was harvested on April 24, 1947. Yield records
are given in Table 7. There were no significant differences in
yield. The number of stalks discarded because of mosaic also

TABLE 7.-CELERY YIELD AND ABUNDANCE OF MOSAIC IN PLOTS
HARVESTED APRIL 24, 1947.
Average ,Num-
Amt. Total Yield Total ber of Aphids
Spray Material* per Num- per Number per 12 Tri-
100 ber Acre Mosaic foliate Leaves
Gals. Crates Stalks April 22

DDT 25% emulsion...... 1 qt. 38.4 545 75 27
DDT 50% wettable ........ 2 lb. 36.9 524 127 55
Toxaphene 25% wettable 4 lb. 36.9 524 85 15
Benzene hexachloride
50% wettable ..-......... 4 lb. 36.7 521 80 28
DDT 50% wettable 2 lb.
Benzene hexachloride
50% wettable .............. 2 lb. 36.2 514 75 47
Check .-.......-...-.............__ 35.3 501 92 36

Total .---...-.-....... .-- ---.....-...... ....... 220.4 534
'F' obtained (Required= 2.71
at 19:1) ..................................... 1.00 1.73
Applied April 11 and 18.






Control of Aphids on Celery


was observed and is shown in Table 7. It was impossible to
measure the effect of the earlier spiay applications made with
the wheelbarrow sprayer on the incidence of mosaic. The aver-
age number of aphids per 12 trifoliate leaves on April 22 is
given in Table 7.
The taste imparted to celery by benzene hexachloride in the
fall has been mentioned. The benzene hexachloride used in the
two experiments was a slightly different formulation. That
used in the spring was claimed to be less likely to impart taste
to vegetables. To check this point, samples of celery from plots
receiving different spray treatments were distributed to several
people for trial. None of the samples were satisfactory in taste
to all those trying them. However, there was no agreement
among them as to the sample that was objectionable. Also, none
of those objecting to any of the samples were able to detect the
characteristic "taste" of benzene hexachloride. From these ob-
servations it would appear that the benzene hexachloride as used
in this experiment did not impart any objectionable taste to the
celery.
SINGLE APPLICATION TRIALS
Early in November, 1946, a commercial field of Supreme Gold-
en celery about six weeks old was infested heavily with Aphis
gossypii. Plots, consisting of three rows 20 feet in length, were
set up in a randomized block. There were four replications of
each treatment. The aphids were so abundant on the plants
that an accurate count was impossible. However, in order to be
sure the infestation was uniform over the area of the experi-
ment, an effort was made to estimate the number fairly closely.
These data are shown in Table 8.
The spray treatments were applied on the morning of No-
vember 8, 1946, with the wheelbarrow sprayer described above.
Materials and dosages used are shown in Table 8. An aphid
count was taken approximately four hours after the spray ap-
plication. The number of aphids on six trifoliate leaves was
determined for each plot, hoping to observe the relative speed
with which the spray materials knocked aphids off the plants.
Although the population on all plots was considerably reduced,
the number of aphids was still high, regardless of spray treat-
ment received. There were no significant differences in aphid
population between treatments. *A second count at the end of
24 hours showed further reduction in the number of aphids on







Florida Agricultural Experiment Station


the plants. However, there were still no significant differences
between treatments.
Aphids were fairly abundant on the ground 24 hours after
treatment. An estimate of the percent dead of the total number
on the ground was made in one plot of each treatment, as shown
in Table 8. There was a tendency for the more effective treat-
ments to show a higher percentage dead of the aphids knocked
off the plant.

TABLE 8.-EFFECTIVENESS OF VARIOUS INSECTICIDES IN CONTROLLING Aphis
gossypii Glov. ON CELERY IN NOVEMBER 1946 AS INDICATED BY COUNTS
MADE 4 AND 24 HOURS AFTER TREATMENT.

4 Hours Before
24 Hours After After Treat-
Amount Treatment Treat- ment
Spray Material per 100 ment Total
Gals. Percent Total Total Aphids
Dead of Aphids Aphids per 24
Aphids on per 24 per 24 Leaves
Ground Leaves Leaves

Chlordane 25% emulsion 1 qt. 50 378 920 2,700
Vapotone ......................... 1 pt.1 50 165 480 3,200
Chlordane 25% emulsion 2 qt. 50 165 405 2,650
Benzene hexachloride
33% wettable 4%
gamma isomer ............ 2 lb. 40 185 780 2,700
Benzene hexachloride
33% wettable 4%
gamma isomer ....... 4 ib. 90 106 850 3,300
Dendrox ........................... 1 qt. 40 87 395 3,600
Vapotone ...................... 1 pt. 100 112 455 2,800
Vapotone ..................... pt. 95 83 240 2,500
Nicotine sulfate ........... 1 pt. 100 141 310 2,400
Vapotone ................. ... 1 qt. 100 158 620 2,300
Benzene hexachloride
33% wettable 4%
gamma isomer ............ 6 lb. 80 26 225 2,500
DDT 25% emulsion ...... 2 qt. 90 33 215 2,400

Total ........ .... ... ...................... ... .......... 1,639 5,895 33,050
'F' obtained (Required =2.56 at 19:1) .......... 1.81 2.07 1.57
SPlus dithane (2 qt.), zinc sulfate (1 lb.), lime (12 Ib.).






Control of Aphids on Celery


Counts of live aphids on the plants were made at the end of
three and six days. The counts made three days after the sprays
were applied are believed to best represent the actual kill of
aphids obtained. These data are presented in Table 9. Although
all materials used gave fairly high kills, chlordane emulsion
even at two quarts per 100 gallons was not satisfactory. Vapo-
tone (1 pint) + dithane-zinc-lime and benzene hexachloride at
two pounds also were significantly poorer than the DDT emulsion
at two quarts. The difference between the vapotone alone and
vapotone plus dithane-zinc-lime is not statistically significant.
However, it raises the question of the advisability of using
this combination. The possibility that all the vapotone sprays
may have been affected by the alkalinity of the water used in
preparing the sprays is discussed in connection with the fol-
lowing experiment.
Results of the six-day count are shown in Table 9. In most
cases this count varied only slightly from the one made three
days earlier. The largest increases in population appear to
have occurred in the case of the three concentrations of benzene
hexachloride and the lowest concentration of vapotone as well as
vapotone plus dithane-zinc-lime. There was no increase in
aphids on the plots receiving nicotine sulfate.
A second series of plots was set up similarly on another farm
on November 14. The initial aphid population was considerably
lower than in the previous experiment. The population was a
mixed infestation of Aphis gossyphi Glov. and A. spiraecola
Patch.
A sample of canal water used in sprays in the preceding ex-
periment was determined to have a pH of 7.15. A sample from
the source of water used in the second experiment indicated a
pH of 7.28. A titration of this latter sample with phosphoric
acid indicated that 11 quarts per 100 gallons would bring the
pH down to 6.0. When 21/ quarts of the acid was used a pH
of 4.2 was obtained. These two concentrations of phosphoric
acid were used in the spray water from the canal prior to
adding vapotone.
The sprays were applied with the equipment used in the pre-
vious experiment. Aphid counts were made in each plot the day
before the treatments were applied. Post-treatment counts were
made at the end of one day and three days. The pre-treatment
counts were used to calculate the percent control. Since the
actual figures for the pre-treatment counts can be calculated







18 Florida Agricultural Experiment Station

TABLE 9.-EFFECTIVENESS OF VARIOUS INSECTICIDES IN CONTROLLING Aphis
gossypii Glov. ON CELERY IN NOVEMBER 1946 AS INDICATED BY COUNTS
MADE 3 AND 6 DAYS AFTER TREATMENT.


Spray Material



Chlordane 25% emulsion ....

V apotone 2 -.............. .............

Chlordane 25% emulsion ....

Benzene hexachloride 33%
wettable 4% gamma
isomer -

Benzene hexachloride 33%
wettable 4% gamma
isom er ....................

Dendrox ...................- .........--

Vapotone ..........................-

Vapotone .............................

Nicotine sulfate ..................

Vapotone ..........................

Benzene hexachloride 33%
wettable 4% gamma
isom er ...............------

DDT 25% emulsion .............


3 Days After
Treatment
Amount Total Num-
per 100 ber Aphids
Gals. per 24 Percent
Trifoliate Control'
Leaves

1 qt. 412 82

1 pt. 224 92

2 qt. 224 91


2 lb. 217 92


4 lb.

1/2 qt.

1 pt.
1 pt.

1 pt.

1 qt.


64

45

43

38

29

26


17

5


98

99

98

98

99

99


99+

99+


Total ........................ ..... ... ....-------

Least significant difference (19:1) ......
'F' obtained (required = 2.56 at 19:1)


1 On the basis of the original infestation before


the treatments were applied.


2Plus dithane (2 qts.), zinc sulfate (1 lb.), lime (1/2 lb.).


from the percentage, it was not deemed necessary to include
them in Table 10. This table includes a list of the treatments
with results of the two counts mentioned above.
As shown in Table 10, even after only 24 hours there were
significant differences between treatments. However, the three-
day counts are considered to give a more reliable indication of
the aphicidal value of the materials which act at varying rates.


6 Days After
Treatment


Total Num-
ber Aphids
per 24
Trifoliate
Leaves

465

383

162


401


111

63

40

104

29

40


46

3


1,344

202
3.04


1,847

205
4.81








Control of Aphids on Celery


The two treatments containing DDT showed up much better at
the end of three days than after one day.
All the spray treatments were significantly better than the
check. Vapotone + bordeaux was significantly poorer than any
of the remaining treatments. Vapotone + dithane (+ zinc +
lime) showed up much better comparatively in this test than in
the preceding one. There was little indication that dithane
(-- zinc + lime) decreased the effectiveness of vapotone. Addi-
tion of phosphoric acid to water used in the spray showed only

TABLE 10.-EFFECTIVENESS OF INSECTICIDES ALONE AND IN COMBINATION
WITH OTHER MATERIALS IN CONTROLLING Aphis gossypii Glov. AND A.
spiraecola Patch. ON CELERY.


Spray Material


Check ............

Vapotone .....................

DDT 50% wettable ....

Vapotone ............- ..........

Vapotone ......................

Vapotone .....................

Nicotine sulfate ..........

Vapotone ......................

DDT 25% emulsion ....

Vapotone .............. .....

DDT 25% emulsion ....


1 pt.

2 lb.

1 .pt.

1 pt.

1 pt.

1 pt.

1 pt.

2 qt.

1 pt.

1 qt.


Other
Material
in Spray


Bordeaux


Dithane


Copper A


Phosphoric
Acid1


Phosphoric
Acid2


T otal ............................... ............ ......
Least significant difference (19:1) ................
'F' obtained requiredd= 2.16 at 19:1) ........


3 Days After
Treatment

Total No.
Aphids Per-
per 24 cent"
Trifoliate Control
Leaves


1,793
146
25.4


24 Hours
After
Treat-
ment
Total No.
Aphids
per 24
Trifoliate
Leaves


77

46

83

99

1,925
112
24.6


11% qt. per 100 gal. Estimated pH-6.0.
2 2% qt. per 100 gal. Estimated pH-4.2.
3 Based on number of aphids present prior to treatment as compared to 3 days after
treatment.







Florida Agricultural Experiment Station


a slightly higher percent kill. On the basis of these data, it
appears that the water in the sprays was satisfactory for use
with vapotone despite the fact that it had a pH above 7.
Wettable DDT gave a fair kill of aphids in this experiment.
Even so, it was significantly poorer than the DDT emulsion at
one quart per 100 gallons., The DDT emulsion at one quart
appeared to be equally as good as two quarts per 100 gallons.
In January a third series of materials was tried, using a plan
similar to the previous two tests. The Pascal celery used in
this experiment was infested with Aphis gossypii Glover. All
counts were made on 12 trifoliate leaves per plot instead of six.
The first post-treatment counts, made at the end of two days,
are given in Table 11. Vapotone + bordeaux proved ineffective
as an aphicide in this experiment and was not significantly
better than the check. The vapotone with copper A again gave a
high kill, as did the vapotone + dry dithane (HE178). A sam-
ple of the water used to make these sprays was determined to
have a pH of 8.9. The chlordane emulsion was not significantly
poorer than the DDT emulsion plus dry dithane. This may be
due to the fact that the chlordane plots had the lowest initial
infestation while the DDT + dry dithane plots had the highest
initial infestation of all the treatments. Since the pre-treatment
counts failed to show any significant differences, it was not con-
sidered necessary to adjust the post-treatment counts.
None of the DDT emulsion treatments proved as effective as
might be expected on the basis of past performance. The DDT
emulsion + dry dithane was significantly poorer than DDT
emulsion + copper A. DDT emulsion alone was not used in
this experiment. The fungicide used appears to affect the tox-
icity of DDT emulsion. Benzene hexachloride was not thus
affected.
Aphids were counted at the end of five and 14 days. No addi-
tional insecticides were applied, but all the plots received weekly
applications of bordeaux. Counts are given in Table 12. The
five-day counts were similar to the two-day counts, but the 14-
day counts were vastly dissimilar. One change during this
period was the sharp reduction in aphid population on the
check plots, possibly through activity of entomogenous fungi.
No attempt was made to measure the percent of aphids affected
by fungi, though very little evidence of their activity was noted.
Also, it is difficult to explain why these fungi would be more







Control of Aphids on Celery


prevalent on the check plots, since all plots received applications
of a fungicide.
The only sprayed plots to show marked reduction in aphids
in the 14-day counts were those receiving chlordane. The vapo-
tone + dry dithane and vapotone + copper A compound plots
still had a low aphid population at the end of 14 days. However,
in view of equally low counts on the check and chlordane plots,

TABLE 11.-EFFECTIVENESS OF INSECTICIDES IN COMBINATION WITH DIF-
FERENT FUNGICIDES IN CONTROLLING Aphis gossypii Glov. ON CELERY.

Amt. 2 Days After Treatment
per Total No. Treatment Percent4
Spray Material 100 Aphids + Least Control
Gals. per 48 Significant
Leaves Difference

Check ..................................... .... 422 60
Vapotone1 ..-............................. 1 pt. 358 .... 45
Chlordane 25% emulsion ...... 1 qt. 330 442 72
DDT 25% emulsion .............. 1 qt. 218 330 42
DDT 25% emulsion' ............ 1 pt. 149 261 43
Nicotine sulfate 2 .................... 1 pt. 105 217 60

Benzene hexachloride 33%
wettable 4% gamma
isomer2 ..... ...... ........-.....-.. 4 lb. 97 209 72
Benzene hexachloride 330%j
wettable 4% gamma
isom er ................................. 4 lb. 82 194 68
Benzene hexachloride 33%
wettable 4% gamma
isomer ................................. 4 1b. 75 187 72

DDT 25% emulsion ............. 1 qt. 58 170 78
Vapotone .................--...---.. 1 pt. i 4 116 99

Vapotone ............................... 1 t. 4 116 98

Total .........----........- ----- ....--- .... .. 1,902
Least significant difference ..........-.. 112
'F' required (19:1) ...................... | 2.10
'F' obtained (19:1) .:- ...... I 12.20_
SPlus bordeaux 8-4-4-100.
2Plus. dry dithane (zinc ethylene bisdithiocarbamate) 2% lbs.
3 Plus copper compound A 4 Ibs.
4 Based on pretreatment counts as compared to the two-day post-treatment counts








Florida Agricultural Experiment Station


it appears unsafe to draw conclusions from this fact. The rain-
fall during the period under consideration was 0.10 inches on
the fourth day and 0.05 inches on the eleventh day following
treatment.
On January 22 a fourth series of spray applications was begun
in plots laid out in a field of Pascal celery. After four treat-
ments had been applied a rainfall of 0.17 inches occurred. The
remaining treatments were not applied until two days later.
The first post-treatment counts were made at the end of three

TABLE 12.-SUBSEQUENT BUILDUP IN APHID POPULATIONS ON CELERY AT
INTERVALS FOLLOWING THE APPLICATIONS OF INSECTICIDES.

Total Number Aphids per 48
Amt. Trifoliate Leaves
Spray Materials per 14 Days 5 Days 2 Days
100 After After After
Gals. Treat- Treat- Treat-
ment ment ment

Vapotone ....... ............ ...... 1 pt. 326 351 358
Benzene hexachloride 33%
wettable 4% gamma isomer' 4 Ib. 301 138 82
DDT 25% emulsion1 .............. 1 qt. 215 105 149
Benzene hexachloride 33%
wettable 4% gamma isomer2 4 Ib. 206 97 97
DDT 25%, emulsion2 ......... 1 qt. 178 176 218
DDT 25% emulsion ............. 1 qt. 162 101 58
Benzene hexachloride 33%
wettable 4% gamma isomer' 4 lb. 161 97 75
Nicotine sulfate 2 ................. 1 pt. 149 94 105
Chlordane 25% emulsion2 ...... 1 qt. 76 322 330
Check ......................... ....... .... 69 423 422
Vapotone ................................... 1 pt. 62 13 4
Vapotone ...................................... 1 pt. 45 34 4

Total .......... .............. ........... 1,950 1,951 1,902
Least significant difference (19:1) ........ 134 106 112
'F' obtained (required =2.10 at 19:1).. 3.34 11.80 12.20
SPlus bordeaux 8-4-4-100.
2 Plus dry dithane 2% lbs.
3 Plus copper compound A 4 lbs.







Control of Aphids on Celery


and five days for the two groups of treatments. Since in the
previous experiment there appeared to be little difference in the
two- and five-day counts, it was decided to ignore the time dif-
ference in the counts. The results and treatments used are
presented in Table 13. All spray treatments gave significant
reductions in aphid population as compared with the check. The
DDT emulsion was significantly better than one and two pounds
of the wettable DDT but was not better than four pounds. The
methoxy DDT was relatively ineffective, being significantly
poorer than either rhothane or wettable DDT at similar dosages.
As in the previous experiment the treated plots received no

TABLE 13.-EFFECTIVENESS OF VARIOUS INSECTICIDES IN CONTROLLING
Aphis gossypii Glov. ON CELERY IN THE EVERGLADES IN JANUARY 1947.

Total Num-
Amt. ber Aphids Plus
Spray Material per per 48 Least Percent2
100 Trifoliate Significant Control
Gals. Leaves Difference

Check ...................................... 525 5
Methoxy DDT 25% wettable.. 4 lb. 290 414 42
DDT 50% wettable ............... 1 lb. 286' 410 48
DDT 50% wettable ................ 2 lb. 2771 401 52
Rhothane 25% emulsion ......... 1 qt. 211 335 65
Pyrexcel .......................:............ 1 pt. 176 300 67
DDT 50% wettable .............. 4 lb. 144 268 72

Rhothane 50% wettable .......... 4 lb. 137 261 75
Vapotone ........... ................... /2 pt. 89 213 83
Benzene hexachloride 33%
wettable 4% gamma isomer 4 lb. 85 209 86
DDT 25%o emulsion ................ 1 qt. 64 188 90
Nicotine sulfate ..... ................... 1 pt. 27 151 95

Total ..................... ...................... ........ 2,311 .
Least significant difference (19:1) ....-- 124
'F' obtained (required = 2.10 at 19:1).. 9.39

1 Counts made five days after application, all others made three days after application.
2 Based on the infestation present prior to treatment.
3 Methoxy DDT = Di (P-methoxy phenyl)-trichloroethane.
SContained 2.8 gr. pyrethrins.+ 28 gr. N-propyl-isome per 100 cc.







Florida Agricultural Experiment Station


further spray except a fungicide until 18 days following treat-
ment. At this time another aphid count was made. Results
are given in Table 14. Again there was a sharp reduction in
the number of aphids on the check plots. However, there was
also a reduction in most of the treated plots. There was even
some reduction in all the wettable DDT plots. The differences
between treatments in the 18-day counts can be noted in the
table.

TABLE 14.-SUBSEQUENT BUILDUP OF APHIDS ON CELERY FOLLOWING
APPLICATION OF DIFFERENT INSECTICIDES.

Total No. Total No.
Aphids Aphids
per 48 Plus per 48
Amt. Trifoliate Least Trifoliate
Spray Material per Leaves Signifi- Leaves 3 Per-
100 18 Days cant & 5 Days cent'
Gals. After Differ- After
Treat- ence Treat-
ment ment

Pyrexcel ................ ............ z pt. 185 176 105
Check ......................... ....... 164 525 31
DDT 50% wettable .......... 1 Ib. 149 227 286 52
Rhothane 25% emulsion .. 1 qt. 103 181 211 49
DDT 50% wettable ........ 2 lb. 103 181 277 37
Vapotone ............................ pt. 99 177 89 111
Methoxy-DDT 25% wet-
table .................-. 4 lb. 81 159 290 28
Rhothane 50% wettable .. 4 lb. 80 158 137 58
Nicotine sulfate ............. 1 pt. 69 147 27 256
DDT 50% wettable ........... 4 lb. 60 138 144 42
Benzene hexachloride 33%
wettable 4% gamma
isomer ...................... 4 lb. 34 112 85 40
DDT 25% emulsion .......... 1 qt. 20 98 64 31

Total ....................... ............... 1,147 2,311
Least significant difference (19:1) 78 124
'F'obtained
requiredd= 2.10 at 19:1) ......... 3.13 9.39


S18th day/three and five days.







Control of Aphids on Celery


In the fifth and final series of treatments, it was decided to
* increase the number of replications of each treatment from four
to five. The sprays were applied on Pascal celery on April 8,
1947, as in the preceding experiments. Results of the three-
day counts with the treatments used are shown in Table 15. All
spray treatments are significantly better than the check. The
poor kill obtained with the benzene hexachloride was unexpected
in the light of previous results. Material used in this test was
a slightly different formulation than that used in preceding four
tests. However, tests against other insects indicated that these
materials were equally effective at similar dosages.
Additional counts were made six and 16 days after treatment.
No spray applications were made during this period. These
data are presented in Table 16. There was a slight reduction in
the population on the check plots between the sixth and 13th

TABLE 15.-RELATIVE EFFECTIVENESS OF VARIOUS INSECTICIDES IN
KILLING APHIDS ON CELERY IN APRIL 1947.

3 Days After Treatment
Amt. Total No. I
Spray Materials per IAphids + Least
100 I per 60 Significant Percent
Gals. Trifoliate Difference Control'
I__ ILeaves

Check-not sprayed ........... .. 484 -66
Benzene hexachloride 50%
wettable 6% gamma I
isomer ............................. I 4 lb. 218 365 I -17
Toxaphene 50% emulsion .... 1 pt. 197 344 34
Toxaphene 50% emulsion .. 1 qt. I 192 339 23
Toxaphene 50% emulsion ... 2 qt. 102 249 65
Toxaphene 25% wettable .... 4 lb. 92 239 61
DDT 25% emulsion .............. 1 qt. 79 226 80
Vapotone ............................ 1 pt. 48 195 79
Nicotine sulfate .................... 1 pt. 48 195 79
DDT 34% emulsion .............. 1V pt. 14 161 95

Total ......... ........... ............. ......... 1,474
Least significant difference (19:1).. 147
'F' obtained
(required =2.15 at 19:1) ............ 7.12 _
1 Based on pretreatment count as compared to three-day count.







Florida Agricultural Experiment Station


days. However, the count on the 13th day indicates the popula-
tion was still considerably higher than on the third day. The
aphid population also increased on all treatments from the third
to the 13th day. Even so, there were still significant differences
between some treatments 13 days after treatment. The four
most effective treatments on the third day still had the lowest
aphid population after 13 days.
Fourteen days after the treatments were applied, all plots re-
ceived an application of DDT emulsion one quart per 100 gallons.
Counts were made at the end of three days. These data are
presented in Table 17. As already shown, there were differences
in aphid population between the previous treatments at the time
the DDT emulsion was applied. Thus it was assumed that an
analysis of covariance might eliminate a part of the error due
to these initial differences. However, the analysis of covariance
revealed that the pre-treatment differences apparently had little
effect on the ret-ultt ('F') required 4.11 (at 19:1) and ob-
tained 2.45. The counts made three days after treatment

TABLE 16.-RATE OF REINFESTATION OF CELERY PLANTS BY APHIDS AS
INDICATED BY COUNTS AT DIFFERENT INTERVALS AFTER TREATMENT.

Total Number Aphids per 60
Amt. Trifoliate Leaves
Spray Material per 13 6 1 3
100 Days Days Days I Pre-
Gals. After After After ITreat-
Treat. Treat. | Treat. ment

Check ............. ......-. ..... .. .. 843 1,036 484 291
Toxaphene 50% emulsion.. 1 pt. 642 443 197 298
Benzene hexachloride 50%
wettable 6% gamma ........... 4 lb. 620 514 218 186
Toxaphene 50% emulsion ...... 1 qt. 548 362 192 251
Toxaphene 50% emulsion ... 2 qt. 425 307 102 290
Toxaphene 25% wettable........ 4 lb. 405 292 92 236
Vapotone ..................... 1 pt. 350 108 48 230
Nicotine sulfate .................. 1 pt. 337 146 48 224
DDT 25% emulsion ....-.......... 1 qt. 243 87 79 388
DDT 34% emulsion .................. 11 pt. 230 50 14 275
Total ............. ..... ............ ....... 4,643 3,345 1,474
Least significant difference (19:1) ......... 250 333 147
'F' obtained (required 2.15 at 19:1).... 5.00 4.69 7.12







Control of Aphids on Celery


are shown in Table 17. The differences between some of the
original treatments are significant. Thus it appears that the
kill of aphids obtained with DDT emulsion may be affected by
the insecticides that have been used previously.

SUMMARY

A number of spraying trials were conducted during 1946 47
to control aphids, mainly Aphis gossypii Glov., on celery. Weekly
applications of DDT wettablee powder) at one pound actual
DDT per 100 gallons resulted in a large increase in the aphid
population. This buildup of aphids did not appear to be due to
the effect of DDT on parasites and predators. The use of
fungicides also appeared to increase the aphid population. This
may have been due to the effect of the fungicides on entomogen-
ous fungi.
Although wettable DDT caused an increase in aphid popu-
lations, DDT as an emulsion, even at one-half the dosage of

TABLE 17.-DIFFERENCES IN KILL OF APHIDS ON CELERY WITH DDT
EMULSION AS AFFECTED BY PREVIOUS USE OF VARIOUS INSECTICIDES.
STotal No.
Amt. Aphids + Least
Spray Material per per 60 Significant Percent
100 Trifoliate Difference Control1
Gals. Leaves

Toxaphene 50% emulsion ... 2 qt. 61 -12
Toxaphene 50% emulsion ... 1pt. 425 -32
Toxaphene 50% emulsion .... 1 qt. 398 19
Benzene hexachloride 50%
wettable 6% gamma isomer 4 lb. 333 27
Toxaphene 25% wettable...... 4 lb. 329 583 47
DDT 25% emulsion ........... 1 qt. 272 526 34
Nicotine sulfate .. ........... ..... 1 pt. 207 461 47
Check .................. .......... ... .... 182 436 39
DDT 34% emulsion ............. 1%/ pt. 122 376 72
Vapotone ........ ......... ...... 1 pt. 97 351 78

Total ...---.....---. ........ ......... ..-- 2,926
Least significant difference (19:1) ...... 254
'F'. obtained (required = 2.15 at 19:1) 2.72 _
1 Based on count just prior to general application of DDT emulsion.






Florida Agricultural Experiment Station


actual DDT, proved to Ie anl effective aphicide. Vapotone and
nicotine sulfate also gave good results against aphids. Benzene
hexachloride was effective in some tests but not in others. Tox-
aphene in the wettable form appeared to have some promise as
an aphicide and appeared to be more effective than the same
material in the emulsion form. Other materials that appeared
unsatisfal ttory as celery aphicides at the dosages tried included:
chlordane (emulsion), rhothane wettablee and emulsion), ro-
tenone plus pyrethrn.um and methoxy DDT wettablee).
The toxicity of some of the materials was affected markedly
by the inclusion of fungicides while with others it was not. Vapo-
tone was ineffective when combined with bordeaux, but did
not seem to be affected by copper compound A or dry dithane.
In one test of vapotone with liquid dithane (plus zinc sulfate
and lime) its toxicity appeared unaffected, while in another
test it appeared that there might be a slight loss in toxicity.
Benzene hexachloride appeared to be unaffected by any of the
fungicides with which it was tried. The DDT emulsion was
not affected by any of the fungicides with which it was tried,
with the possible exception of dry dithane.
No injury to celery plants was observed with any of these
insecticides at the dosages tried.
The addition of phosphoric acid to the water used in making
the sprays to lower the pH (normally 7-9) did not appear
to increase the effectiveness of vapotone.
From a practical standpoint the DDT emulsion appears to
be the most satisfactory celery aphicide of any of the materials
tested. In addition to being a good aphicide, it is of value in
reducing injury caused by cutworms. Benzene hexachloride,
while effective in some tests, was not consistent in its perform-
ance. Another disadvantage is the possibility that it may impart
an objectionable taste to the celery, especially if applied too near
harvest time. Vapotone and nicotine sulfate gave excellent kills
of aphids. However, neither of them was satisfactory in killing
cutworms. An additional disadvantage of vapotone is that it
cannot be used in combination with certain fungicides, especially
bordeaux.




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