LEAFLET No. 24
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Cotton Insect Control
F. S. ARANT, Entomologist
Agricultural Experiment Station
W. A. RUFFIN, Entomologist
Extension Service
ONLY three dusting treatments of
the many tested in 1947 were found
to be suitable and effective for cotton
insect control in Alabama. These are:
Chlorinated camphene, 20 per cent
Benzene hexachloride-DDT, 3-5 mix-
ture
Calcium arsenate alternated with
calcium arsenate-nicotine.
The experiments were conducted by
the Alabama Agricultural Experiment
Station to find out which of the many
new insecticides on the market are
best. Reported here are control rec-
ommendations based on experimental
results.
INSECTICIDES to USE
Chlorinated camphene, 20 per cent.
This insecticide was highly effective in
the control of boll weevil and boll-
worm in all experiments. It was not
effective in eliminating heavy 
cotton
aphid populations. However, 
where
used throughout the season, there 
was
no build-up in numbers of aphids. 
In
these tests, which were 
repeated sev-
eral times, the plots dusted 
with chlori-
nated camphene yielded 
403 to 827
more pounds of seed 
cotton per acre
than undusted plots.
BHC-DDT, 3-5 mixture. This dust,
which contains 3 per cent gamma ben-
zene hexachloride and 5 per cent DDT,
gave excellent control of all three-boll
weevil, bollworm, and cotton aphid.
It gave the quickest kill of boll weevil
of any of the dusts tried. However,
its period of effectiveness was shorter
than that of chlorinated camphene or
calcium arsenate. In one large experi-
ment, the average gain in seed cotton
per acre over no dusting was 496
pounds from the use of BHC-DDT, as
compared with gains of 164 pounds
from applications of calcium arsenate
and 571 pound pounds from dustings of
chlorinated camphene.
BHC-DDT is irritating to the opera-
tor of the dusting equipment.
Calcium arsenate alternated with
calcium arsenate-nicotine. Alternate
applications of calcium arsenate and
calcium arsenate containing 2 per cent
nicotine gave excellent control of boll
weevil and cotton aphid. These dusts
were not very effective against boll-
worm, which caused severe damage in
1947. In these tests, dusting with cal-
cium arsenate and nicotine resulted in
338 more pounds of seed cotton per
acre than no dusting. On the other
hand, calcium arsenate used alone
AGRICULTURAL 
EXPERIMENT 
STATION
ofthe ALABAMA 
POLYTECHNIC 
INSTITUTE
Auburn, Alabama
M. J. Funchess, Director
MARCH 1948
(without nicotine mixture) gave an
increase of only 164 pounds of seed
cotton per acre over the yield of the
undusted plots.
If bollworms become numerous in
fields dusted with calcium arsenate-
nicotine, it may be necessary to make
one or two applications of 10 per cent
DDT to kill the worms.
Price Factor.-Many growers have
asked about the relative value of
chlorinated camphene or BHC-DDT
dust as compared to calcium arsenate-
nicotine mixture. Experimental re-
sults to date indicate that the new ma-
terials give better control of cotton
insects than alternate applications of
calcium arsenate and calcium arsenate-
nicotine. Therefore, growers can af-
ford to pay as much per pound for
chlorinated camphene or BHC-DDT as
the current price of calcium arsenate
containing 2 per cent nicotine.
THESE NOT RECOMMENDED
Certain insecticides are not recom-
mended because of unfavorable results
obtained from experiments conducted
throughout the cotton-growing states.
These include:
Boll weevil spray. A commercial
boll weevil spray sold last year in Ala-
bama was tested in several states. It
was found to be of no value in the
control of cotton insects.
Chlordane-DDT, 3-3 mixture. A mix-
ture containing 3 per cent chlordane
and 3 per cent DDT was sold in sev-
eral states last season. This mixture
was tested by State and Federal agen-
cies; it was found to be of little value
against boll weevil. Actually its use
resulted in an increase in aphid dam-
age to cotton.
Chlordane. A dust containing 5 per
cent chlordane was tested in Alabama.
It did not control boll weevil as well
as calcium arsenate, and its use re-
sulted in increased damage from the
bollworm. In experiments elsewhere
10 per cent chlordane showed great
promise as a boll weevil insecticide. At
this strength it killed adult weevils as
well as young grubs in the squares.
However, this material is still in the
experimental stage, and is not ready
for general use on cotton. It is avail-
able for those who wish to use it on a
trial basis.
Boll Weevil Catchers. Boll weevil
catchers were tested last season in sev-
eral states. Some were found to be
effective in collecting weevils and
other insects on small cotton. However,
the number of beneficial insects col-
lected usually far exceeded the harm-
ful forms. The use of boll weevil catch-
ers did not eliminate the need for dust-
ing later in the season; neither did the
use of these machines materially in-
crease the yield of cotton.
WHEN to DUST COTTON
Ordinarily cotton in Alabama does
not require dusting early in the sea-
son-before the plants are fruiting
freely. Boll weevils emerging from
hibernation in the spring and early
summer live for only a short period.
If insecticides are applied at this time,
the only weevils killed are those that
would die without poisoning. Usually
other insect pests are not numerous
enough to warrant dusting early in the
season.
Results of experiments conducted
by the Alabama Station in 1947 indi-
cate that early dusting of cotton with
the new recommended insecticides 
may
not only be unnecessary but actually
harmful unless continued through 
the
season until the bolls mature. Where
three early dustings were made at 5-
day intervals, beginning when the cot-
ton began squaring, less cotton was
produced in each of four fields than
where no dust was applied. 
On the
other hand, profitable increase in yield
resulted when dusting was delayed 
and
five applications were made during the
time the cotton crop was being set and
matured.
The most profitable control of cot-
ton insects results from dusting while
the cotton plants are setting and ma-
turing the crop. After the plants are
fruiting freely, squares should be ex-
amined for boll weevil punctures.
When 20 or more are punctured out
of each 100 examined, it is time to be-
gin dusting. Three applications of
dust should be made at 5-day intervals.
One week following the third dusting,
the cotton should be examined again.
If weevils are swarming or the number
of squares punctured exceeds 20 in
100 examined, two to three additional
dustings should be made at 5-day in-
tervals. If there is no evidence of in-
sect damage, no dust should be applied.
However, additional frequent inspec-
tions should be made until the bolls are
mature. If insect damage or swarming
of weevils occurs at any time before
the bolls are mature, the cotton should
be dusted at 5-day intervals until the
insects are under control. Very late
dustings are often the most profitable
of all. It is a grave error to stop dust-
ing several weeks before the bolls are
mature on the assumption that there
will be no further insect damage.
AMOUNT of DUST NEEDED
If dusting has not been started too
early, 6 to 7 applications of dust should
be enough for the season. The average
rate per application is 10 pounds per
acre for chlorinated camphene and
BHC-DDT, and 8 pounds for calcium
arsenate and calcium arsenate-nico-
tine. Each grower should stock in ad-
vance 60 pounds of dust for each acre
of cotton. If calcium arsenate is to
be used, one-half of the dust (30
pounds for each acre) should contain
nicotine.
The amount of dust needed may be
increased by frequent rainfall or heavy
insect damage. If an application of
calcium arsenate is washed off within
24 hours, the dusting should be re-
peated. Results to date indicate that
applications of BHC-DDT or chlorinat-
ed camphene need not be repeated if
the insecticide remains on the cotton
12 to 15 hours without rain. The
BHC-DDT mixture kills many weevils
within 4 to 6 hours after dusting.
HOW to APPLY the DUST
The insecticides may be applied with
ground machinery or by airplane.
Ground machinery (hand-operated,
mule-drawn, or tractor equipment)
should have a distributor over each
row covered. The dust should be blown
through the foliage in a thin cloud that
completely envelops the plants. The
air should e relatively calm when dust
is applied.
Where ractor dusters are used, care
must be taken late in the season to
prevent damage to the cotton by the
nmachinery. The speed of the tractor
should be reduced and guards should
be provided to prevent the wheels
crushing bolls on the ground. A large
sweep placed just above the surface
of the ground and in front of each
wheel will lift boll-laden branches out
of the path of the wheels. Sheet metal
guards may also be 
used.
PRECAUTIONS
Cotton dusts are poisons and should
be treated as such. They should not
be dusted on pastures or on maturing
food and feed crops. The odor of ben-
zene hexachloride may persist in the
soil for a long time. Until more in-
formation is available, the dust should
not be applied in fields where soil
crops, such as potatoes, are to be
grown the following season.
Any dust left over at the end of the
season should be stored in the original
container and in a dry place inacces-
sible to livestock. Empty containers
should not be left where livestock can
lick them.
Prolonged breathing of dusts should
be avoided.
SLC.,K P0ft es APRIL 10