Dosages of Insecticides to Control the Boll Weevil and the Bollworm

Abstract

Field-plot expts. were conducted at Waco, Tex., in 1942 to determine the effectiveness of reduced dosages of Ca arsenate against the boll weevil and whether cryolite could be substituted for Ca arsenate in its control. The comparative effectiveness of Ca arsenate, basic Cu arsenate, Pb arsenate, and cryolite against the bollworm were also studied. Boll weevil infestations were too light to show any marked results but one expt. showed that Ca arsenate reduced the weevil infestation to lower levels (average of 11.9%) than did similar dilutions of cryolite (av. of 13.9%). For bollworm control 16-lb. applications of Ca arsenate gave a significantly higher gain in yield (398 lb. of seed cotton per acre) than did 8-lb. applications (225 lbs.). Dosages of approx. 8 lb. per acre of basic Cu arsenate, Pb arsenate, or cryolite resulted in a significantly higher gain in yield than similar dosages of Ca arsenate, the gains being 462, 446, 442, and 252 lb. per acre, respectively.