18 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE, 1944 
BOLLWORM 
Despite a high survival and heavy egg deposition early in the season, 
high temperatures and natural enemies greatly reduced boll worm 
damage. The most important predator was Orius ihsidiosus Say, 
though a number of other predators were factors in destroying over 
2 > percent of the eggs at Waco, Tex. Fewer bollworm eggs are de- 
stroyed when aphids are sufliciently numerous to provide an abundance 
of food for predators. This helps to explain why bollworms often 
increase following the use of arsenicals, which are known to cause a 
rapid increase in populations of aphids. 
Cryolite diluted with 15 to 30 percent of sulfur gave as good boll- 
worm control as the same poundage of undiluted cryolite, probably 
because the diluted cryolite has better dusting qualities and plant 
coverage. Greater dilutions were effective if the poundage of the 
mixture was increased so that 8 pounds of cryolite per acre was used. 
Cryolite-corn meal bait (1; 9 dry mixed) applied at 40. GO, and 80 
pounds per acre gave satisfactory bollworm control. Forty or more 
pounds of bait per acre, scattered by hand, gave good plant coverage 
and gains equal to those obtained with 8 pounds of cryolite dust. 
Reduced dosages of insecticides have not proved satisfactory for 
the bollworm; in fact, the recommended dosages are too smail for 
best control. In 2-year tests the usual dosage of 8 pounds of calcium 
arsenate per acre gave an average gain in yield of 173 pounds of seed 
cotton per acre, 12 pounds of calcium arsenate gave 187 pounds, and 
16 pounds of calcium arsenate 195 pounds. A 1 : 2 and a 1 : 1 mixture 
of basic copper arsenate and sulfur at 16 pounds per acre gave average 
gains of 195 and 300 pounds of seed cotton, respectively. A spray of 
8 pounds of basic copper arsenate per acre was as effective as a 1 : 1 dust 
mixture of basic copper arsenate and sulfur or calcium arsenate dust at 
16 pounds per acre. 
Calcium arsenite was found to be more toxic against the bollworm 
than calcium arsenate, but caused so much injury to the plants it is 
not safe to use. A 1:9 mixture of dinitro-e>-cyclohexylphenol and 
sulfur was less effective than calcium arsenate, and a 1:1 mixture of 
phenoxathiin and bentonite gave very little control. 
PLANT BUGS AND STINKBUGS 
It was necessary to begin control of plant bugs and stinkbugs about 
2 weeks earlier and to continue control measures for a longer period 
in 1^)4:} than normally. Large quantities of arsenical-sulfur diM mix- 
ture used in Arizona gave good control when dusting was started early 
and suflicient applicat ions were used. In plot tests gains of 220 to 
:,71 pounds of seed cotton per acre were obtained with 5 commercial 
mixtures. A mixture containing 5 percent of calcium arsenite in 
sulfur caused plant injury and a loss of 22 pounds per acre. 
In an airplane- dusting experiment six applications of a 1 : 2 mixture 
of calcium arsenate and sulfur at 15 pounds per acre produced a gain 
in yield of 271 pounds of seed cotton per acre, or .°»0 percent, as com- 
pared with a gain of 15S pounds, or 10 percent, last year. 
EFFECTIVENESS OF DDT ON COTTON INSECTS 
In preliminary experiments against several cotton insects in Louisi- 
ana, Texas, and Arizona, DDT was found to be less effective against 
