Status of Velvetbean Caterpillar Control in Alabama

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Abstract
Expts. on insecticidal control of the velvetbean caterpillar, Anticarsia gemmatilis, were conducted in Ala. during a major outbreak of the pest on peanuts in 1946 Studies were made also of DDT residues on peanut hay following dusting and the effect of these residues on animals. Single applications of DDT, cryolite, and benzene hexachloride to replicated plots approx. 0.01 acre in size gave protection against serious insect damage from Aug. 20 to harvest, Sept. 19. Infestation counts revealed that DDT was effective over the longest period and benzene hexachloride the shortest. Dusted plots produced higher yields than those not dusted. On peanuts yielding at the rate of approx. 900 lbs. per acre without insecticidal treatment, avg. per acre gains from dusting were as follows: cryolite (2 expts.) 371 lbs.; 1%DDT (2 expts.) 427 lbs.; 3% DDT (2 expts.) 297 lbs.; 5% [gamma] benzene hexachloride (1 expt.) 440 lbs.; 1%[gamma]benzene hexachloride (2 expts.) 240 lbs. of peanuts. Spray residue studies revealed that DDT persisted on peanut foliage several weeks after dusting. The amt. of DDT on peanut hay varied from 2 to 31 ppm. Eight of 13 samples of hay analyzed contained in excess of 7 ppm. tentative tolerance for certain foods. All samples below the tolerance were from fields on which approx. 6 in. of rain fell over the 4- to 5-week period between dusting and harvest. Livestock fed DDT-dusted hay and unshucked corn for 102 to 143 days stored DDT in the fat and passed it in the milk. The amt. stored in the fat varied from 13 ppm. in pigs to 160 ppm. in steers. A calf suckled by a cow fed DDT-dusted hay stored 825 ppm. in its fatty tissues. All animals appeared normal. The hay in the feeding expts. contained considerably more DDT than was found on peanut hay under field conditions.

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