Tests with benzene hexachloride for the control of insects attacking peanuts, 1946-1949

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May 1951 E-820

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

I

TESTS WITH BENZENE HEXACHLORIDE FOR THE CONTROL
OF INSECTS ATTACKING PEANUTS, 1946-1949

By F. W. Poos and T. N. Dobbins, Division of Cereal and Forage
Insect Investigations, and E. T. Batten and G. M. Boush,
Virginia Agricultural Experiment Station


The direct application of either technical benzene hexachloride or
lindane to soil in which peanuts are to be planted immediately or in which
peanuts are growing is not recommended. However, in view of the wide-
spread concern about the flavor of peanuts grown in soil containing
residues of these insecticides, the results of experiments conducted
with them for the control of insects attacking peanuts at Beltsville, Md.,
and in southeastern Virginia during 1946 to 1949 are presented herein.
Results of previous experiments were reported by Poos et al. (3), by
Dobbins and Fronk (1), and by Fronk and Dobbins (2).
DDT had been found effective against the tobacco thrips (Frankliniella
fusca (Hinds)) on seedling peanuts and against the potato leafhopper
(Empoasca fabae (Harr.)) on the peanut foliage, but at least 65 pounds
per acre were found necessary in the soil to control the southern corn
rootworm (Diabrotica undecimpunctata howardi Barber). Experiments
comparing benzene hexachloride with DDT were therefore undertaken.

Tests in 1946

Benzene hexachloride-/ was first applied to peanut foliage for control
of the tobacco thrips in 1946 at Beltsville, Md., and Holland, Va. (Poos
et al. 3). At Beltsville an emulsion of benzene hexachloride was applied
as a spray to seedling peanuts on June 24 and July 3 and 9. The emulsion
was prepared by adding 1-1/3 ounces of a 50-percent emulsifiable con-
centrate (gamma isomer 10 percent) to 1 gallon of water. The control of
thrips on the treated plots was good, and the increase in yield was as


1/ References to benzene hexachloride in this paper indicate the
technical material, although concentrations and dosages are given in
terms of the gamma isomer.





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great as that on plots treated with a 4-percent DDT emulsion. An
insecticide residue equivalent to 13.4 p.p.m. of organic chlorine in
excess of that found on untreated foliage was reported on the samples
collected on October 8 from the five plots treated with benzene hexa-
chloride. However, a 2-percent DDT dust was applied to these plots
on July 30 and August 8 to control the potato leafhopper, and the DDT
could account for some of the organic chlorine.
At Holland benzene hexachloride dust containing 1 percent of the
gamma isomer was applied with hand equipment to small plots of
seedling peanuts on May 24 and June 5 and 18, to determine the effec-
tiveness of this insecticide against the tobacco thrips. Control was
definitely better than that obtained with a 2-percent DDT dust applied
to comparable plots. Neither of these dusts was so effective as a spray
containing 4 percent of DDT. No insecticide residues were present on
any of the samples of hay collected from these plots in November.

Tests in 1947

Applications to the soil. --Benzene hexachloride dust was first
applied to soil for the control of the southern corn rootworm and other
coleopterous larvae at Holland in 1947 (Dobbins and Fronk 1). Two
dosages were used on two comparable series of 1-square-rod plots.
There were four replications of each treatment in each series. The
first series of plots was treated on June 24 and the second on July 14.
Four pounds of dust containing the desired strength of active ingredient
were applied to each plot. The dusts were broadcast by hand as uniformly
as feasible and worked into the upper 1 to 2 inches of soil with a garden
rake. Estimates of larval injury to pods were made on September 9. A
minimum of 100 pods from each plot was examined, and the results are
summarized in table 1. Benzene hexachloride applied to the soil on
June 24 or July 14 at dosages of 0.5 or 1 pound of the gamma isomer per
acre significantly controlled the southern corn rootworm.


2/ The Division of Insecticide Investigations of this Bureau made all
the chemical analyses mentioned in this report, unless otherwise noted.
Determinations of organic chlorine were made by the procedures recom-
mended by the Association of Official Agricultural Chemists in their
Methods of Analysis 1950, pp. 367-424. Corrections were made for
comparable determinations in untreated materials. Amounts of 1 p.p.m.
and less are of doubtful accuracy. The organic-chlorine content was
converted to benzene hexachloride by multiplication by the factor 1.36.






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Table 1. --Injury to peanut pods by coleopterous larvae following
applications of benzene hexachloride dust to the soil. Holland, Va.,
1947

m Pods injured
Gamma
Treatment isomer Treated on June 24 Treated on July 14
Treatment isom er ------------------------_-
per By southernBy other By southern B o
Bother other
acre corn root- larvae corn root- larvae
larvae larvae
worm worm

Pounds Percent Percent Percent Percent

Benzene hexachloride 0.5 16 0.6 13 3.5
1 9 .4 12 2.1
Untreated 49 .6 38 3.3
Difference required
for significance at
5% level 15.3 15.7


Personnel at the Tidewater Field Station of the Virginia Agricultural
Experiment Station and several visitors tasted the raw peanuts grown on
these plots and detected no off-flavor.

Applications to the foliage. --An emulsion of benzene hexachloride
containing 0.1 percent of the gamma isomer (prepared from a commercial
10-percent emulsifiable concentrate, and an impregnated dust containing
1 percent of the gamma isomer were applied to small plots of seedling
peanuts at Beltsville in 1947 for the control of the tobacco thrips.
The plots were sprayed on June 12, 18, 20, and 30 with a knapsack
sprayer having a conventional disk-type nozzle. A heavy rain fell
immediately after the spraying on June 18, which was therefore repeated
on June 20. Observations on July 1 showed that 87 percent of the leaves
on the plants treated with benzene hexachloride were uninjured as com-
pared with 94 percent uninjured on plants treated similarly with a 4-percent
DDT emulsion.
In the plots treated with the impregnated benzene hexachloride dust by
means of a rotary hand duster 72 percent of the leaves were uninjured as
compared with 69 percent in the plots treated with a 2-percent DDT dust.
Observations made early in October to determine the effect of the dust
applications on the injury to pods by coleopterous larvae indicated no
consistent differences between dusted and untreated plots.
Pods from three plants selected at random from each of the five
sprayed plots were examined on October 3 to determine the percentage
showing insect injury. The reduction in pod injury resulting from the





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benzene hexachloride spray was highly significant. In the treated plots
only 6 percent of the pods were injured by the southern corn rootworm
and 4 percent by other coleopterous larvae, whereas, in the untreated
plots 29 percent were injured by the rootworm and 10 percent by other
larvae.
Samples of forage were taken on September 30 from the variously
treated plots, air-dried, and analyzed for organic chlorine. From these
analyses the following values were computed.

P.p.m.
Benzene hexachloride:
Emulsion None
Dust 4.9

DDT:
Emulsion 3
Dust 2.2

A benzene hexachloride dust containing 1 percent of the gamma isomer
was applied to seedling peanuts for control of the tobacco thrips at
Holland on May 23 and June 6 and 24. On June 24 a count of the leaves
and injured leaflets on 60 randomly selected plants in each plot showed
78 percent control as compared with only 16 percent obtained with the
2-percent DDT dust. No organic chlorine was found by chemical
analyses of samples of forage taken from these plots in November just
before the crop was picked.

Tests in 1948

Applications to the foliage. --At Holland, from June 19 to August 23,
1948, seven applications of several insecticides, including benzene
hexachloride in dusts containing 1 or 2 percent and in emulsions con-
taining 0.5 percent of the gamma isomer, were applied to the foliage
with hand equipment to control the southern corn rootworm (Fronk and
Dobbins 2). The results, given in table 2, indicate that good control of
this insect in peanuts can be obtained with frequent applications to the
foliage. Benzene hexachloride gave significantly better control than
any of the other insecticides.
No increased amounts of organic chlorine over those in untreated
samples were found by chemical analysis of foliage samples taken
separately from the dusted and sprayed plots on October 18. Samples
of shelled peanuts harvested separately from these plots on October 20
were reported to contain less than 1 p.p.m., if any, of benzene hexa-
chloride.





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Table 2. --Infestation and yield of field-cured peanuts from plots in
which the foliage was treated seven times with benzene hexachloride
to control the southern corn rootworm. Holland, Va., 1948


Approximate
Treatment total gamma Infested Yield
isomer per pods per acre
acre

Pounds Percent Pounds
Dusts
Untreated check 71 1,955
Benzene hexachloride, gamma isomer
1 percent 1.05 10 2,526
2 percent 1.82 7 2,250
Difference required for significance
at 5-percent level 9

Emulsions
Untreated check 78 1,955
Benzene hexachloride, gamma isomer
0.5 percent 0.049 25 2,576
Difference required for significance
at 5-percent level 6


At Beltsville benzene hexachloride was applied on June 25 and July 2
and 12 to the foliage on small plots of peanuts in comparison with DDT
to control the tobacco thrips. Plots were also examined for injury by
coleopterous larvae. In one test five plots were treated with an emulsion
containing 0.5 percent of the gamma isomer and five plots with a 2-percent
DDT emulsion. In another test six plots were treated with a dust con-
taining 1 percent of the gamma isomer and six plots with a sulfur dust
impregnated with 1 percent of DDT. The results of these tests, given
in table 3, indicate that in spray form benzene hexachloride was approxi-
mately as effective as DDT against the tobacco thrips; and in dust form
it was more effective than DDT. All the plots in these experiments were
treated on July 26 and August 2 and 13 with a 1-percent impregnated
DDT-sulfur dust, but the plots treated earlier with benzene hexachloride
had fewer pods injured by coleopterous larvae than those treated with
DDT.





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Table 3. --Effect of three applications of benzene hexachloride or DDT to
peanut foliage on the injury by the tobacco thrips and coleopterous
larvae. Beltsville, Md., 1948

Tobacco thrips
Approximate r-obcc---- Pods injured
Treatment total active Average by
retet.injured b
ingredient leaflets Control coleopterous
___ per acre per leaf / larvae

Pounds Number Percent Percent
Emulsions
Untreated check 1.25 66
Benzene hexachloride,
gamma isomer 0.5 percent 1.1 .26 79 25
DDT 2 percent 4.6 .21 84 53
Difference required for significance:
At 5-percent level .11 20
At 1-percent level .15 27

Dusts
Untreated check 1.15 44
Benzene hexachloride,
gamma isomer 1 percent 0.7 .17 86 4
DDT 1 percent, in sulfur .7(DDI) .44 62 45
Difference required for significance:
At 5-percent level .16 17
At 1-percent level .22 23


1_/ Each peanut leaf has 4 leaflets.

Application to the soil. --At Holland tests with DDT and benzene
hexachloride were conducted on plots of Virginia Jumbo peanuts planted
on May 24, 1948. 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 in the other
by the same method that was used in conducting similar tests during 1947.
The results are given in table 4.
The June applications were more effective than the July applications.
All treatments significantly reduced the amount of pod injury caused by
the southern corn rootworm, and the June 3 treatments also gave con-
siderable control of the tobacco thrips.






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Table 4. --Injury to peanut pods by larvae of the southern corn rootwoi m
and control of tobacco thrips following applications of benzene hexa-
chloride and DDT dusts to the soil. Holland, Va., 1948

Pods affected by rootworms Tobacco
Gamma ------I------,
C iamma Injured Penetrated thrips
Treatment isomer control
........... control
per acre Treated Treated Treated Treated June 24
June 3 July 7 June 3 July 7

Pounds Percent Percent Percent Percent Percent


Untreated checks 86 84 78 68 -
Benzene hexachloride 0.5 25 36 16 25 47
1 8 28 4 20 60
l/ 1.5 7 21 3 13 63
DDT- 18 42 10 29 84
Difference required
for significance:
At 5-percent level 9 14 -
At 1-percent level 13 20 -


1/ 67 pounds per acre applied on June 3 and 100 pounds on July 7.

To determine the yield, in October the plants in the two inside rows
of each plot were dug, bundled, and artificially dried, and the peanuts
were picked with a mechanical picker and weighed. There were significant
increases in yield on plots treated with benzene hexachloride at 1 and 1.5
pounds of the gamma isomer applied on June 3 and from all the July treat-
ments. Chemical analyses of several samples of field-cured peanuts
(in the shell) from the plots in which benzene hexachloride had been used
gave somewhat erratic results. Twelve additional samples of shelled
peanuts from these plots were reported to have a benzene hexachloride
content of less than 1 p.p.m., if any. No off-flavor was detectable in the
unprocessed nuts or, in preliminary tests, in roasted nuts.

Tests in 1949

Applications to the foliage. --In 1949 a suspension spray containing
1 percent of lindane was applied to five small plots of seedling peanuts
at Beltsville on June 15 and 22 for control of the tobacco thrips, and
additional applications were made on July 7, 28, and August 17 for
control of the southern corn rootworm. From June 29 to July 1 highly





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significant (83 percent) control of the injury caused by the tobacco thrips
was found by counting leaves and injured leaflets. The early-season
growth of the treated plants was much greater than that of the untreated
checks. Differences in plant growth could be detected up to the middle
of August.
These plots were examined on October 4-9 for injury to pegs and pods
by the southern corn rootworm. The lindane treatment gave 90 percent
control over the untreated check. Three samples of forage collected
from the lindane-treated plots on October 10 and air-dried showed an
average organic-chlorine content of 12 p.p.m. more than the untreated
check. These five plots had been treated on August 15 with a sulfur dust
impregnated with 1 percent of DDT for the control of the potato leafhopper,
and the DDT could account for some of the organic chlorine.
At Holland nine insecticide formulations were applied with hand
equipment on June 15 and July 6 and 27, and August 18 to peanut foliage
on small plots each 2 rods long by 1 rod wide for control of the southern
corn rootworm. The plots were examined for rootworm injury to pegs
and pods on October 11 and, as in previous tests, the control obtained
with benzene hexachloride was highly significant. Infestations were
recorded as follows: Untreated plots 62 percent, plots treated with
benzene hexachloride dust (gamma isomer 2 percent) 5 percent, and
plots treated with benzene hexachloride emulsion sprays (gamma isomer
1 percent) 6 percent. A composite sample of the hay taken from these
plots on October 5, air-dried, and analyzed was reported to contain a
benzene hexachloride residue of 3 p.p.m. for the dust and 22 p.p.m. for
the emulsion. The variation in the weights of mature nuts obtained from
one 33-foot row in each plot appeared tO be associated with the treatment,
although the increases in yield were not significant at the 5-percent level.
Data from these plots indicated that the proportion of sound meats was
highly significantly greater in the treated plots than in the untreated
plots.

Applications to the soil. --At Holland two series of identically arranged
1-square-rod plots were given similar soil treatments with lindane and
benzene hexachloride, one series on June 6 and the other on June 23.
Each treatment was replicated four times. In order to obtain maximum
rootworm infestation the plots were located in an area of the field that
normally was poorly drained. However, because of unusually heavy
precipitation (36.29 inches) from June through September the plots were
flooded to such an extent that infestation by the southern corn rootworm
was markedly below normal and no significant differences were recorded
between treated and untreated plots in either series. The excessive
rainfall may have caused greater-than-normal absorption of benzene
hexachloride by the nut meats. Composite samples of shelled peanuts






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collected on October 20 from two plants from each plot were analyzed
for organic-chlorine content. The results calculated to benzene hexa-
chloride are shown in table 5.

Table 5. --Benzene hexachloride residues reported in samples of shelled
peanuts grown in soil treated with lindane or benzene hexachloride.
Holland, Va., 1949


Date applied Gamma isomer Benzene
Treatment June 1949 per acre hexachloride
content

Pounds P.p.m.

Lindane 6 0.5 4.5
1 .2
1.5 .8
23 .5 0
1 0
1.5 1.8
Benzene hexachloride 6 1 1.9
23 .5 1.9
1 1.8


Tests with soil treatments on plots each 16 rows wide and about
950 feet long were also conducted at Holland in 1949. Unreplicated
treatments with lindane and benzene hexachloride dusts were applied
with a 2-row fertilizer distributor, such as is commonly used on peanuts
in this area. The dusts were immediately plowed into the upper 2 to 3
inches of soil. Estimates of rootworm injury to nuts and pegs were made
at various intervals from August 11 to October 3. The differences in
injury between the treated and untreated plots were highly significant,
but there were no significant differences among the various treatments.
This was true of the injury caused by the tobacco thrips from data
recorded on June 24, as well as that caused by the southern corn root-
worm. A summary of the results is given in table 6.
Three areas in each of the seven plots were harvested separately
and the field-cured nuts were weighed. Each of these areas consisted
of the eight middle rows 100 feet long, or about 1/5 acre. Because
excessive rainfall delayed digging and caused many of the nuts to come
off in the soil, the yields recorded from two of the areas in each plot
were obviously not comparable. The other area of each plot, harvested
separately, was on higher ground and provided more comparable yields;





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the increases of field-cured nuts from the treated plots ranged from 16
to 45 percent. Three samples of shelled peanuts from each plot were
analyzed for organic-chlorine content and were reported to average
from 2 to 8 p.p.m. (table 6) of benzene hexachloride.

Table 6. --Effect of benzene hexachloride and lindane dusts applied to
the soil on infestation by the tobacco thrips and the southern corn
rootworm and the benzene hexachloride residue in shelled nuts.
Holland, Va., 1949


Percent Percent Percent P.p.m.


Fertilizer separate
1 Lindane, 1
2 Untreated
3 Lindane, 0.75

In fertilizer
4 Lindane, 1.25
5 Benzene hexachloride
gamma isomer, 1
6 Lindane, 1
7 Untreated
Difference required for significance:
At 5-percent level
At 1-percent level


0.7- 6
11 -73
2 -12


1 4

0 7
.3- 7
17 -66


12.6
16.8


Several peanut growers in Virginia applied benzene hexachloride in
fertilizer to small areas of from 0.42 to 1.38 acres for control of the
southern corn rootworm in 1949. On only four farms was it possible to
obtain what appeared to be reasonably reliable comparisons of yields
between treated and untreated areas. The results are given in table 7.
Two growers applied sufficient benzene hexachloride to give 1 pound of
the gamma isomer mixed with 499 pounds of 0-12-12 fertilizer per acre,
and the other two, 400 pounds of the fertilizer with sufficient benzene
hexachloride to give 0.8 pound of the gamma isomer. Infestation counts
indicated that adequate control of the rootworm was obtained with either
dosage. However, the yield of peanuts was not always increased. The
treated peanuts matured earlier than the untreated ones, and the delay in
digging the treated peanuts caused many of them to be left in the soil.







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Tests on Flavor and Acceptability

Samples of the field-cured peanuts harvested from the plots indicated
in table 6, as well as other samples taken from outlying areas that had
been treated with benzene hexachloride by farmers in 1949, were sub-
mitted to a nuniber of agencies for tests of various kinds. The available
results of these tests are briefly reported here.

Tests made by the Bureau of Plant Industry, Soils, and Agricultural
Engineering. --At Beltsville, J. H. Beattie roasted peanuts and made
peanut butter from samples of peanuts from each of the seven plots
denoted in table 6. He reported objectionable off-flavor in peanuts from
plot 5 only, which had been treated with benzene hexachloride.
Mr. Beattie kindly furnished the authors samples of the roasted peanuts
and the peanut butter he prepared from plots 1, 5, and 7. When these
samples were submitted to various amateur tasters, 13 out of 14 re-
ported the peanut butter made from peanuts from plot 5 to be objection-
able and 14 of 23 reported off-flavor in the roasted peanuts from this
plot. Only two of these tasters reported slight off-flavor in plot 1
(lindane treated), one in the roasted peanuts and one in the peanut butter.

Tests made at Cornell University. --Samples of two lots of peanuts
that had been grown in Moyock fine sandy loam soil in Isle of Wight
County, Va., were sent to W. A. Rawlins, at Cornell University, for
taste tests. He reported that 85 percent of the judges noted off-flavor
in the peanuts grown in the soil treated with benzene hexachloride at
1 pound of the gamma isomer per acre. All these judges considered the
flavor of the treated peanuts less desirable than that of the untreated
peanuts. This was chiefly a test of preference and the judges were not
asked to comment on palatability.

Tests made by peanut-processing companies. --Samples from the plots
indicated in table 6 were also tested for flavor by the Planters Nut and
Chocolate Company, Suffolk, Va. The nut meats were cooked in peanut
oil. Peanuts from plots 1, 4, and 6 were reported to be slightly off-
flavor. One sample of peanuts that had been artificially dried on the
vines immediately after being dug was also reported slightly off. Among
six other samples tested by this company, which were taken from areas
that had been treated with benzene hexachloride by farmers, a "strong
earth flavor" was reported in one sample and a slight off-flavor in two.
Of 10 untreated samples of peanuts submitted, only the one artificially
dried was reported off-flavor. All the samples submitted were identified
by number only before being tested.





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Samples of seven lots of peanuts identified by number only were
submitted to Lummis & Company at Suffolk for testing. Three of the
lots were grown in untreated soil and four in soil treated with benzene
hexachloride or lindane. These tests were made on peanuts roasted in
the shell and roasted shelled, and peanut butter. A slight to strong
chemical flavor was reported in all but one sample, which was untreated
and reported "roasted too high, no off-flavor noted." Obviously factors
other than benzene hexachloride may cause off-flavor in peanuts.
Samples of shelled peanuts from plots 5, 6, and 7 (table 6) were
also submitted to the Miner Laboratories, Chicago, Ill., through the
Miller Peanut Company, Albany, Ga. They reported that no off-flavor
or off-odor was clearly detected in the raw nuts, although slight differences
in odor were reported by several judges. Portions of the samples were
cooked in oil at 290o-325 F. for 15 minutes. In both blanched and
unblanched nuts a decided musty flavor was detected by 10 judges in the
nuts from plot 5 that had been treated with benzene hexachloride.
Similar off-flavor in unblanched peanuts from plot 6 treated with lindane
was detected by 4 judges, and in blanched peanuts by 6 judges. The
report states that apparently all judges are not equally sensitive to off-
flavor caused by benzene hexachloride in peanuts, and that the skins on
peanuts may sometimes obscure the off-flavor. A few tests suggested
that, if the off-flavor caused by benzene hexachloride in peanuts is not
too strong, it may not be detected when eaten simultaneously with peanuts
having no off-flavor.

Tests made by the Bureau of Human Nutrition and Home Economics. --
Palatability tests were made on 10-pound samples of shelled peanuts
grown on plots 2, 5, and 6 (table 6), and the quality of the peanut oil
from peanuts grown on the same plots was evaluated in cooking and
palatability tests. The tests on the peanuts were conducted by Gladys L.
Gilpin and Nancy Smalley, and their results are shown in table 8.
The peanuts grown in soil treated with benzene hexachloride and
lindane were comparable in flavor, but both were scored slightly lower
than the sample from untreated soil. Off-flavor was observed in the
treated samples, whether the peanuts were judged unroasted, oven-
roasted, or oven-roasted and salted. Several judges considered the off-
flavor in the unroasted treated samples to be moderately strong and two
found it to be very strong. Off-flavor for the two treated samples were
similar when judged unroasted. Oven-roasted peanuts grown in soil
treated with benzene hexachloride had a moderately strong off-flavor,
whereas those from lindane-treated soil had a slightly strong off-flavor.
Moderately strong off-flavor was also observed in samples prepared by
roasting and salting. The difference in quality was more noticeable in
the roasted and the roasted and salted nuts than in unroasted nuts.





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Table 8. --Palatability scores-1 for peanuts grown in untreated soil, and
in soil treated with benzene hexachloride or lindane (plots 2, 5, and
6 in table 6). Highest possible score is 5;


Preparation Natural Absence of General
of peanuts Treatment flavor off-flavor acceptability

Unroasted Untreated 3.4 3.2 3.2
Benzene hexachloride 3.2 2.7 2.8
Lindane 3.2 2.8 2.7

Oven-roasted Untreated 3.6 3.7 3.5
Benzene hexachloride 3.1 2.2 2.3
Lindane 3.3 3.0 2.9

Oven-roasted
and salted Untreated 3.5 3.8 3.5
Benzene hexachloride 3.0 2.3 2.4
Lindane 2.9 2.6 2.6


/ Average of 3 replicates rated by 6 judges.

On the basis of these palatability scores, peanuts had stronger off-
flavor and lower acceptability scores when grown in soil treated with
benzene hexachloride or lindane than when grown in untreated soil.
The quality of the oil made from peanuts grown on the same plots
was evaluated in cooking and palatability tests by Elsie H. Dawson and
Patricia Trimble. The Planters Nut and Chocolate Company supplied
2-quart samples of cold-pressed peanut oil (refined-washed-dried)
from peanuts grown on each plot, to be used for french-frying Florida
Long White new potatoes. The palatability of the potatoes cooked
simultaneously in the three lots of peanut oil was evaluated by a panel
of six judges. Tests with the same oil were conducted on three con-
secutive days, enough fresh oil being added to make up the required
quantity. Two of the judges noted a musty flavor in the initial batch of
potatoes cooked in oil from peanuts grown in soil treated with benzene
hexachloride, but this off-flavor was not noted in two successive batches
of potatoes fried in the same oil. It is possible that any off-flavor can
be removed by frying a single batch of potatoes in the oil. There was
no appreciable difference between average acceptability scores for
three batches of potatoes french-fried in the same oil, whether the oil
was from peanuts grown in untreated soil, in soil treated with lindane,
or with benzene hexachloride.






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SUMMARY

Benzene hexachloride, first applied to foliage of peanuts for control
of the tobacco thrips (Frankliniella fusca (Hinds)) at Beltsville, Md., and
Holland, Va., in 1946, compared favorably with DDT in effectiveness
against this insect. Emulsion sprays containing 0.1 to 1 percent and
dusts containing 1 or 2 percent of the gamma isomer applied to peanut
foliage on small plots from 1947 through 1949 gave significant control
of the southern corn rootworm (Diabrotica undecimpunctata howardi
Barber) and the tobacco thrips. In most tests no insecticide residue was
reported on samples of foliage taken from the plots at harvest time, and
all samples of shelled peanuts harvested separately from the dusted and
sprayed plots in 1948 were reported to contain less than 1 p.p.m., if any,
of benzene hexachloride.
Benzene hexachloride, first applied as dusts to the soil on small plots
at Holland in 1947 for control of injury to peanut pods by coleopterous
larvae, gave best results at the rate of 1 pound of the gamma isomer per
acre in June. Applications of dusts and emulsion sprays on small plots
in 1948 confirmed these results and gave control not only of the southern
corn rootworm but also of the tobacco thrips. All applications made in
June were more effective than those made in July. No off-flavor was
detectable in the unprocessed nuts tested during 1947 and 1948. In
preliminary tests no off-flavor was detected in the roasted nuts grown
in soil treated with benzene hexachloride.
Field tests with benzene hexachloride and lindane in 1949 indicated
that applications to the soil of 0.8 to 1 pound of the gamma isomer per
acre, either with fertilizer or separately, gave significant control of
the southern corn rootworm and the tobacco thrips on peanuts. Yields
of field-cured peanuts were increased, and the proportion of sound meats
was highly significantly greater in the treated plots than in the untreated
plots. Chemical analyses indicated benzene hexachloride contents ranging
from 0 to 7 p. p.m. in samples of shelled peanuts from plots receiving
these treatments.
Taste tests indicated off-flavor in the peanuts grown in treated soil;
also that off-flavor may be caused by other factors. Amateur judges
noted off-flavor caused by lindane less frequently than that caused by
benzene hexachloride. There was little difference in the quality of oils
made from peanuts grown on plots treated with these insecticides when
judged by the quality of potatoes french-fried in these oils.
In view of the off-flavor found in peanuts grown in soil treated with
benzene hexachloride or lindane, the application of these insecticides to
soil in which peanuts are to be planted immediately or in which peanuts
are growing, is not recommended.




UNIVERSITY OF FLORIDA
11 I li fl ll II I 1 I 1 1 1
3 1262 09239 6026
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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) Fronk, W. D., and Dobbins, T. N.
1949. Insecticide tests for control of the southern corn rootworm
in peanuts. U.S. Bur. Ent. and Plant Quar. E-782,
10 pp. [Processed./

(3) Poos, F. W,, Grayson, J. M., and Batten, E. T.
1947. Insecticides to control tobacco thrips and potato leafhopper
on peanuts. Jour. Econ. Ent. 40: 900-905.