Insecticide tests for control of the southern corn rootworm in peanuts

MISSING IMAGE

Material Information

Title:
Insecticide tests for control of the southern corn rootworm in peanuts
Physical Description:
10 p. : ; 27 cm.
Language:
English
Creator:
Fronk, W. Don ( William Don ), 1920-
Dobbins, T. N
United States -- Bureau of Entomology and Plant Quarantine
Publisher:
U.S. Department of Agriculture, Agricultural Research Administration, Bureau of Entomology and Plant Quarantine
Place of Publication:
Washington, D.C
Publication Date:

Subjects

Subjects / Keywords:
Insecticides -- Testing   ( lcsh )
Spotted cucumber beetle -- Control   ( lcsh )
Peanuts -- Diseases and pests -- Control   ( lcsh )
Genre:
bibliography   ( marcgt )
federal government publication   ( marcgt )
non-fiction   ( marcgt )

Notes

Bibliography:
Includes bibliographical references (p. 10).
General Note:
Caption title.
General Note:
"E-782."
General Note:
"July 1949."
Statement of Responsibility:
by W.D. Fronk and T.N. Dobbins.

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 030295327
oclc - 780190315
System ID:
AA00025193:00001

Full Text


July 1949


United States Department of Agriculture
% Agricultural Research Administration
Bureau of Entomology and Plant Quarantine



INSECTICIDE TESTS FOR CONTROL OF THE SOUTHERN CORN ROOCIOM IN PEANUTS /

By W. D. Fronk, Virgini., Agricultural Experiment Station, and
To N. Dobbins, 2J/ Division of Cereal and Forage Insect Investigations



Each year the peanut crop in the Virginia-North Carolina commercial
peanut-growing region is attacked by the southern corn rootworm (Diabrotica
undecimmpunetata howardi Barber). This injury has become more severe in the
last few years, perhaps owing in part to & succession of wet growing seasons.
On heavy, poorly drained land such injury may run as high as 80 percent of
the total yield of the field-cured peanuts. The larva causes the damage by
cutting through the shell of the pod and feeding on the kernels. Even where
little feeding occurs, the openings made in the pods permit the entrance of
moisture and soil microorganisms, which cause decay or deterioration of the
kernels. Many of the pistils, or "needles," may also be attacked soon after
they enter the ground and thus be prevented from producing nuts.
Fink (2) was the first to report injury to peanuts by the southern
corn rootworm. More recently Miller (4) stated that in Virginia this
rootworm was the most important underground insect pest of peanuts.
Grayson and Poos (Q) found that an application to the soil of 25, 50, or
100 pounds of DDT per acre gave reductions of 47 to 84 percent in numbers
of pods injured by this insect. They also found in one small test that
three applications of a 0.66-percent DDT spray to the peanut foliage
reduced the infestation by 52 percent. Tests by Dobbins and Fronk (1) at
Holland, Va., showed that 25 pounds of DDT or sufficient technical benzene
hexachloride to give 0.5 pound of the gamma isomer per acre mixed into the
top 2 inches of soil significantly reduced the amount of injury to the
pods, but that effective control required a minimum of 1 pound of the
gamm iaomer or 100 pounds of DDT per acre.

Significant reduction in pod injury was also achieved at Beltsville,
Md., by treating peanut foliage on June 12, 18 (followed immediately by
heavy rain), 20, and 30 with emulsions containing 0.1 percent of the
gama isomer of benzene hexachloride, 0.1 percent of chlordane, or 4 per-
cent of DDT. The use of water sprays containing 0.05 percent of parathion
or 001 percent of toxaphene in the form of wettable powders gave negligible
control,


V/ Investigations conducted cooperativelyby the Virginia Agricultural
Experiment, Station and the Bureau of Entomology and Plant Quarantine,

2/ The authors are indebted to E. T. Batten, in charge of the Tide-
water Field Station of the Virginia Agricultural Experiment Station, at
Holland, Va., for invaluable cooperation in these studies.


UL


E--782






-2-

This paper presents the results of tests of insecticides applied to
the soil or to the foliage in small plots of peanuts at Holland, Va., and
Beltsville, Md., during 1948 for the control of the southern corn rootworm.
Although effective control was obtained with some of the insecticides used
in these tests, further trials on a field basis and additional information
on the best formulations and dosages to use, the best time to apply them,
and possible residue hazards are necessary before these materials can be
safely recommended.

All formulations of benzene hexachloride referred to in this paper
were made from the technical material, although concentrations and dosages
are given in terms of the active, or gamma, isomer. All samples collected
for determining residues of insecticides were air-dried unless otherwise
indicated.

Applications to the Soil
Two series of plot tests were conducted on Virginia Jumbo peanuts at
Holland. 'DDT and benzene hexachloride dusts were broadcast by hand over
the soil and raked into the upper 1-2 inches with a garden rake. The
dosage of the active ingredient for each plot was diluted with pyrophyllite
to make 4 pounds of dust. The dust was placed in paper bags (two 2-pound
lots) in order to facilitate distributing the materials uniformly over the
plots. Each plot contained 6 rows and was 1 square rod in area. Each
treatment was replicated five times in a Latin square. Applications were
made on June 3 in one series and on July 7-8 in the other to peanuts
planted on May 24. Plants were dug from each plot on September 8 for
estimating the damage to the pods. The results are summarized in table 1*


Table 1.-Effect of benzene hexachloride and DDT dusts applied to the soil
on the injury to developing peanut pods by southern corn rootworm larvae.
Holland, Va.

: Active : : Pods penetrated
Dust : ingre- : Injured pods : by rootworm
: dient : June 3 W July 7 : June 3 : July 7
: per acre: treatments: treatments: treatments: treatments
Pounds Percent Percent Percent Percent

Untreated checks 86 84 78 68

Benzene hexachloride
(gamma isomer) 0.5 25 36 16 25
1 8 28 4 20
1.5 7 21 3 13

DDT 1001/ 18 42 10 29

Difference required for significance:
At 5-percent level 9 14
At 1-percent level 13 20


Y/ Only 67 pounds applied June 30





-3-


Preliminary data were also obtained on the effectiveness of parathion,
toxaphene, and chlordane in comparison with benzene hexachloride against
the southern corn rootworm. The applications were made on June 3 in one
series and on July 8 in another. Each treatment was duplicated on each
date. An estimate of larval injury was taken on September 7-8. The results
are summarized in table 2,

Table 2.-Preliminary tests with parathion, toxaphene, chlordane,
and benzene hexachloride dusts in the soil to control injury to
peanut pods by southern corn rootworm. Holland, Va.

: Active :Injured pods
Dust :ingredient : June 3 : July 8
: per acre : treatments : treatments
Pounds Percent Percent

Untreated checks 61 76

Benzene hexachloride
(gamma isomer) 1 7 9

Parathion 2 36 40
5 10 22
10 2 12
Toxaphene 20 21 34
40 5 22
Chlordane 10 29 25

Difference required for significance:
At 5-percent level 21 25
At 1-percent level 31 37


These results, considered with those shown in table 1, indicate that
the June applications of all the insecticides were more effective than the
July applications. All treatments significantly reduced the amount of pod
injury. The treatments with benzene hexachloride at 1 and 1.5 pounds of
the gamma isomer, with 5 and 10 pounds of parathion, and with 40 pounds of
toxaphene per acre were the best and approximately equal in effectiveness.
Since 1 pound of the gamma isomer of benzene hexachloride or 5 pounds of
parathion gave very effective control, it is probable that 0.75 pound of
the gamma isomer or 4 pounds of parathion per acre may give satisfactory
control if the application is made at the right time.

To obtain yield samples, the plants in the two inside rows of each
plot were dug, bundled, and artificially dried. The peanuts were picked
from these samples by means of a mechanical picker and weighed. The results
are summarized in table 3. Of the treatments applied on June 3, the
following gave significant increases in yield: Benzene hexachloride at 1
and 1.5 pounds of the gamma isomer, parathion at 5 pounds, toxaphene at
40 pounds, and DDT at 67 pounds to the acre. All the July treatments
except parathion at 2 pounds to the acre gave considerable increases in yield.






-4-


p- 0 4Q


U) I
01
QIO~
~


C".

4>
4)

0

0
CO










0




A,


t k


, 0 0<




0)
Cd







r4)
40




44'

(4

4-1


0)
^',


0) <





i
44 4**


4)
0
0














0
0
C)



0}
54
4)


I


c.-
*r40
00
0

'do



0 UN'
24


0


%r'-4 ~
cr~
H H


Hto


%rq -l* %0 N f% UN 0%
>) to C Y0 t- 1






Or%~t E-- C N o N CY
41% Cq cm w) %0


M r-i r-I
%0 0%O%


02
0



co
43
*g 0



Sii


Hl H


0 0


0
A I


tf\ If\
* 0
0HH


0 -M%'O
00 C- o 00


5.4
4) 3-*


to




t o
H T
0!
0540


.d<- 0




I
0--
4->4


s
.r






tU)
PC


0
0'















004
1k.,





|f

i.-.





P41 020


P4 H t<-0a

014 hEO


^4t

0a






4)0


'I-'






-5-


Applications to the Foliage


At Beltsville.- Plots of peanuts that had the foliage treated three
times with an insecticide to control the tobacco thrips (Frankliniella fusca
(Hinds) were also examined for injury by the southern corn rootworm. The
applications were made on June 25, July 2, and July 12. Two experiments
were conducted for the purpose of comparing the effectiveness of various
formulations, one with emulsions (five replications of each treatment) and
a second with dust formulations (six replications of each treatment). In
the second experiment parathion emulsion was substituted for chlordane dust,
which failed to arrive as planned. The emulsion sprays were applied by
means of a knapsack sprayer fitted with a Monarch-type oil-burner nozzle,
and the dust mixtures were applied with a rotary hand duster. To control a
heavy infestation of potato leafhoppers, all plots were treated on July 26
and August 2 and 13 with a 1-percent impregnated DDT-sulfur dust. Estimates
of southern corn rootworm injury to the pods were made on September 14-15
and are summarized in table 4.

Table 4.--Effect of three applications of insecticides to peanut foliage on
the injury to peanut pods by southern corn rootworm larvae. Beltsville, Md.

: Approximate :
: total active : Injured pods
Formulation : ingredient : :
: per acre : Average : Range
Pounds Percent Percent

Experiment 1
Untreated checks 66 58- 76
Benzene hexachloride,
0.5-percent (gamma isomer) emulsion 1i1 25 9 41
Toxaphene, 0.75-percent emulsion 1.7 58 47- 70
DDT, 2-percent emulsion 4.6 53 43- 65
COLordane, O. 5-percent emulsion 1,1 30 4-54
Difference required for significance:
At 5-percent level 20
At 1-percent level 27

ESeriment 2
Untreated checks 44 15 -65
Impregnated DDT-sulfur, 1-percent dust J,7 45 11 76
Parathion, 1-percent dust o7 26 8-52
Benzene hexachloride,
1-pereent (gamma isomer) dust .7 4 2- 9
Toxaphene, 10-percent dust 6.9 10 0 22
Parathion, 0.2-percent emulsion .45 41 13 59
Difference required for significance:
At 5-percent level 17
At 1-percent level 23






-6-


In these tests emulsions containing 2 percent of DDT or 0.75 percent
of toxaphene were of little value in controlling the southern corn rootworms
Emulsions containing 0.5 percent of the gamma isomer of benzene hexachloride
or 0.5 percent of chlordane gave significant control. The control obtained
with dusts containing 1 percent of the gamma isomer or 10 percent of toxa-
phene was comparable to that obtained at Holland with the most effective
soil treatment. However, the infestation at Holland was considerably
heavier than that at Beltsville. With parathion the 1-percent dust gave
some control, but the 0.2-percent emulsion was ineffective. DDT applied to
the foliage either as a 1-percent dust or as a 2-percent emulsion gave no
control of this insect. The excellent results obtained with dusiv contain-
ing 10 percent of toxaphene and 1 percent of the gamma isomer were un-
expected in view of the heavy rainfall at Beltsville during the 1948 growing
season. Here again the much lower infestation by this insect at Beltsville
must be taken into consideration.

At Holland.- Experiments were conducted on square-rod plots of
Virginia Jumbo peanuts to test the efficiency of several insecticides in
controlling the souL -rn corn rootworm by means of applications to the
foliage. Each treatment, was replicated five times. Seven applications
were made to each plot at intervals of approximately 2 weeks from June 19
to August 23. The large number of applications were made in order to
obtain maximum control. The dust mixtures were applied with a rotary hand
duster, the emulsions with a knapsack sprayer equipped with a Monarch-type
oil-burner nozzle, and the wettable-powder formulations with a knapsack
sprayer equipped with a Mohawk nozzle. On September 13 plants were dug
from each plot for estimating the damage to the pods, and on October 18
the plants in the two inside rows from each plot were dug for yield
determinations. The results are summarized in table 5.

All the dust treatments gave significant control, but benzene hexa-
chloride gave much better control than any of the others. Among the
sprays, benzene hexachloride at 0.5 percent of the gamma isomer, 0.5 and
1 percent of chlordane, and 0.5 percent of toxaphene gave significant
control. Again the benzene hexachloride was significantly better than
any of the other treatments,
Tests for Harmful Residue/

DDT.- Trials by Dobbins and Fronk (1948) and Grayson and Poos (1947)
had shown that applications of DDT to peanut foliage gave little promise of
practical control of the southern corn rootworm. During 1948, therefore,
DDT was tested only by applications to the soil for comparison with
results obtained during previous years. Since it was thought at the time
that it was not absorbed by plants, no samples of foliage or nuts were
taken from the treated plots for chemical analysis to determine whether or
not they contained any DDT.

Benzene Hexachloride.- Analyses of several samples of field-cured
peanuts (in the shell) from plots in which benzene hexachloride had been
used as a soil insecticide at the rates of 0.5, 1, or 1.5 pounds of the
gamma isomer per acre gave somewhat erratic results. Twelve additional
samples of shelled peanuts that had been grown on plots that had received
1 or 1.5 pounds of the gamma isomer per acre, also applied to the soil,
either on June 3 or July 7,were reported to have a benzene hexachloride
2/ The Division of Insecticide Investigations made all the chemical
analyses mentioned in this paper.







-7-


\ v0OQO-4 QOC Q
UV\ q4R'BrOHcv R J O


UN %0
Itr C-.
CY' U-%
r-4 CV


4-3
0
4,5
bp
0
bo


0 0

H O
0-cS





ol
0) 0


4,-
0C)
4 0
4,-











:- 0
C -H
0














all
0 0
5.40

tQ20





0301




0)C


Pi0
H U)
cSD






0
01\ C
0) 4,
HQ)O(
.o u2.
"I< s


OtO-.%OH -"OUCt-O
1- r- 0 H N0-t00I
HH0HOor cM- \O'C
HHli-


.9 .9 9* *.


4)
4>
0



I) o


0 i-i 0 o


U 0)





.9 9* ** 99


0)
4*H *
Ul4


M '9o


4,4)


004 04^

00
40) pQ>
SCl

000

g A0

t3 E-4


4-,
04
0



0)



020

C.)
p4










4')
0

0


0)


5-4


0.r
0)0o


0 4)
0~
o :0)


to L- 9 *
0* 0 0


4-3
P ,P 0)0
-H 0) 0)54


4)o 4




5-4 0 O

0) Q
H
ii U>

34^


iia
0


0
54
V
p4


%0 CMto to %-o
r-< Cst cli i
tCI4 RM a Oi


" 6



w to




4 3 r.
00
5451
S0)
P.04
I I


54 > 0)0
0 &p Q4





0 *
0) 4,

m p4


co -Ng CM No 0 -t N-
t-C N 10 cm El-C*-t~-


0)
0)




.4
o
4,
5;:


H

4-3
U)

0



0-









04
4'







Cd











t'
*H



(Df



DId
0


0

1>1

Cd
0)t






frl
0r
'hU)
HJ1
H<






-8-


content of less than 1 p.p.m., if any. Samples of foliage taken on
October 18 from plots that had received seven applications of benzene
hexachloride dust containing 2 percent of the gamma isomer or of a spray
containing 0.5 percent of the gamma isomer during the period June 19 to
August 23 showed no organic chlorine. Samples of shelled peanuts harvested
on October 20 from the plots that had been sprayed seven times with 0.5,
1, or 2 percent of the gamma isomer were also reported to contain less than
1 p.p.m., if any, of benzene hexachloride.

Chlordane.- The analyses of samples of field-cured peanuts (in the
shell) grown on plots to which 10 pounds of chlordane had been applied to
the soil either on June 3 or on July 8 showed no residue. Additional
analyses of shelled peanuts from the same plots confirmed these results.
Peanut foliage taken on October 6 from plots that had received applica-
tions of a 0.5-percent emulsion on June 25 and July 2 and 12, and of
1-percent DDT-impregnated sulfur dust (a total of about 70 pounds per acre)
on July 26 and August 2 and 13 showed 3 p.p.m. of organic chlorine.
Samples of foliage taken on October 18 from plots that had received seven
applications of 10-percent chlordane dust or 0.5-percent chlordane emul-
sion during the period June 19 to August 23 contained, respectively, 7.7
and 8.6 p.p.m. of organic chlorine.

Parathion.- Less than 0.1 p.p.m., if any, parathion was reported from
analyses of unshelled peanuts taken on October 20 from plots to which 2,
5, or 10 pounds of parathion had been applied to the soil either on June 3
or on July 8. Samples of peanut foliage taken in October, and air-dried,
from plots to which parathion had been applied to foliage as indicated
below, were analyzed without finding any evidence of parathion.

Pounds of parathion
Formulation Time of application per acre-application

1-percent dust June 3, 15, and 23 0.25
June 25, July 2 and 12 .23
0.2-percent emulsion Same .15
2-percent dust 7 times from June 19 to Aug. 23 .31

Toxaphene.- The analyses of samples of field-cured peanuts in the shell
that had been grown on plots that received toxaphene at the rate of 20 or
40 pounds per acre on June 3 or July 8 indicated no residue. Analyses of
additional samples from these plots, which included shelled nuts, confirmed
the previous results. The results of analyses of samples of peanut foliage
taken at harvesttime in October from plots to which toxaphene was applied
are given below:

(1) Samples from plots that had been treated with a 10-percent dust
on June 25 and July 2 and 12 at approximately 2.3 pounds of toxaphene per
acre-application, plus a dust containing 1 percent of DDT in sulfur applied
on July 26 and August 2 and 13 at approximately 0.23 pound of DDT per acre-
application, contained 0.5 p.p.m. of organic chlorine.

(2) No residue was found in samples treated on the sane dates as in
(1) with an emulsion containing 0.75 percent of toxaphene at approximately
0.57 pound per acre-application.






-9-


(3) Samples of forage taken from plots that had received seven appli-
cations of 10-percent dust or 0.5-percent suspension at approximately 1.9
and 0.012 pounds per acre-application during the period June 19 to August 23
contained, respectively, 17.5 and 0 p.p.m, of organic chlorine*

Other Observations

The treated peanuts matured earlier than the untreated peanuts. The
nuts from the plots treated with benzene hexachloride were of a much
better quality than those from the untreated check plots. The benzene
hexachloride dusts also seemed to reduce the injury from wilt (Sclerotium
rolfsii), which was severe during 1948 in the field in which these tests
were conducted. No off-flavor was detectable in the unprocessed nuts
grown under the conditions of these tests. Preliminary tests to investi-
gate the effect of benzene hexachloride as a soil treatment on these peanuts
after processing gave negative results.

Despite the promising results obtained on small areas, none of the
insecticides or methods of application discussed in this paper are recom-
mended for use by growers until more is known about methods and time of
application, effect on plant growth in various types of soil, the possibility
of undesirable residual effects on peanuts or on crops grown in rotation
with peanuts, and the possibility of harmful residues on or in crops eaten
by man and animals*


Summary

Losses of field-cured peanuts caused by the southern corn rootworm
(Diabrotica undecimpunctata howardi Barber) on heavy, poorly drained land
ran as high as 80 percent of the total yield as determined by counts of
injured pods. These losses became progressively greater in the Virginia-
North Carolina commercial peanut-growing area during the years 1945-1948
than in previous years.

During 1948 significant control was obtained at Holland, Va., with
certain organic insecticides broadcast as dusts by hand over the soil of
small plots and raked into the upper 1-2 inches. These materials and the
dosages per acre were as follows: Technical benzene hexachloride at 1 or
1.5 pound of the gamma isomer; 5 pounds of parathion, 40 pounds of toxa-
phene, and 67 pounds of DDT. Applications made on June 3 were more effec-
tive than those on July 7-8.

Three applications to peanut foliage of manulsions containing technical
benzene hexachloride or chlordane, at the rate of approximately 0.38 pound
of the active ingredient per acre-application,gave significant control at
Beltsville, Md., where the infestation was less severe than in southeastern
Virginia. At Beltsville dust mixtures containing technical benzene hexa-
chloride or toxaphene applied at approximately 0.23 and 2.3 pounds of active
ingredient per acre-application, respectively, also gave excellent control.





UNIVERSITY OF FLORIDA

3 1262 09239 2066

Seven applications of certain formulations were made to the foliage
on small plots of peanuts at Holland, Va., during the period June 19 to
August 23, in order to obtain maximum control. The following formulations
gave significant control: In dust form 1 and 2 percent of the gamma isomer
of technical benzene hexachloride, 2 percent of parathion, 5 and 10 percent
of chlordane, and 10 and 20 percent of tcxaphene; in emulsion form,
0.5 percent of the gamma isomer of benzene hexachloride and 0.5 and 1 per-
cent of chlordane. Benzene hexachloride gave significantly better control
than any of the other insecticides.

Literature Cited

(1) Dobbins, T. N., and Fronk, W. D.
1948. Insecticide tests for the control of coleopterous larvae
attacking peanuts in the soil. Jour. Econ. Ent. 41: 815-816.

(2) Fink, D. E.
1916. Injury to peanuts by the twelve-spotted cucumber beetle.
Jour. Econ. Ent. 9: 366-368.

(3) Grayson, J. M., and Poos, F. W.
1947. Southern corn rootworm as a pest of peanuts. Jour. Econ.
Ent. 40: 251-256.

(4) Miller, L. I.
1943. A white grub injuring peanuts in eastern Virginia. Jour.
Econ. Ent. 36: 113-114.