8 ANNUAL REPORTS OF DEPARTMENT OP AGRICULTURE, 195 1 
More than a dozen chemicals were used in several dozen formula- 
tions. Leading insecticides now used on cotton Include calcium arsen- 
ate, sulfur, benzene hexachloride, toxaphene, DDT, aldrin, dieldrin, 
chlordane, parathion, paris green, nicotine, and TEPP. It is esti- 
mated that approximately 200 million pounds of sulfur, either alone 
or mixed with other materials, was dusted on cotton in L950. 
Community- Wide Experiments Increase Quantity and Improve 
Quality of Cotton 
Experiments on the control of cotton insects through early-season 
application of insecticides on a community-wide basis were condu 
in central Texas in L950. Here the cotton fleahopper and several 
species of thrips are injurious early in the season. The boll weevil is 
the mosl destructive. The bollworm appears later in the season and 
is the most difficult cotton insect to control. 
All the cotton fields on 36 farm- in 2 communities near Waco re- 
ceii ed 3 early-season applical ions of insecticides for control of cotton 
insects. More than 3,600 acres were treated on these farms. ( 
parable untreated farm- in two communities were used a- checks. 
The untreated communities comprised approximately L,000 acres on 
IT farm-. Sprays were used on 93 percent of the acreage and dusts 
on 7 percent. Application dates ranged from May 21 to June L5. 
The early applications gave seasonal control of thrips and flea- 
hoppers. The} 7 also gave seasonal control of the boll weevil on 90 
percent of the acreage. 
There were no mid-season or late-season treatments. Despite omis- 
sion of the late-season treatment-, there was no damage by the boll- 
worm, as would ordinarily be expected. Beneficial insects, which were 
plentiful in all field-, prevented serious damage in several fields where 
bollworm infestations were threatening. 
Early-season treatment speeded early fruiting to the extent that 
the treated cotton matured and was harvested ii to :; week- earlier 
than the untreated cotton. Jt was possible to destroy most of the 
cot ton st alks by Sepember 3< '. and nearly all were dest roved by ( October 
15. Protection of the crop from insect damage also resulted in the 
product ion of high-grade cotton. 
Iii the two communities the average acre production of lint cotton 
was 171 pound- from the treated and 270 pound- from the untreated 
col loii. a gain of 20 I pound- of lint cot Ion an acre. The net pro! it was 
$74.84 an acre, or $269,575 on the total acreage. 
The new approach to control of cotton insects, with modifications, 
may have wide application in the Cotton Belt. If so, it will signifi- 
cant ly reduce the requirements for insecticides, manpower, and equip- 
ment to protect the crop from insect attack. 
Many Insecticides Effective igainsl Boll Weevil 
Studies during the year show that the boll weevil may be effectively 
controlled with benzene hexachloride, calcium arsenate, toxaphene, 
aldrin, and dieldrin. Benzene hexachloride should he applied at a 
rule of not less than 0.3 pound of gamma isomer an acre, calcium 
ar enate at V i<> L0 pounds, toxaphene :it 2 t" 3 pound- of the technical 
grade, aldrin at 0.25 t" () ..'» pound, and dieldrin at 0.15 to o.i pound. 
