Gaines W. Eddy

Toxicity to fly larvae of the feces of insecticide-fed cattle.

Studies were conducted on the toxicity to newly hatched house fly larvae ( Musca domestica L.) of the feces of cattle fed 25 different compounds. The materials were incorporated in the animals’ diet for 5 days and fecal samples collected for tests at different intervals during feeding and after it was discontinued. Fourteen of the 25 compounds were not completely lethal to the larvae at the dosages tested. Bayer 22408 ( O,O -diethyl O -naphthalimido phosphorothioate) and Co-Ral® ( O -(3-chloro-4-methylumbelliferone) O,O -diethyl phosphorothioate), the two most effective materials, were lethal to the larvae when administered to the animals at dosages as low as 1 mg./kg. Comparative data are presented on the susceptibility of newly hatched larvae of the house fly, stable fly ( Stomoxys calcitrans (L.)), and horn fly ( Siphona irritans (L.)) to four of the more effective insecticides.

Control of Mosquito Larvae in Log Ponds in Oregon

DDT, heptachlor, and malathion emulsions at 1, 3, and 6 pounds of technical material per surface acre were used in tests for the control of mosquito larvae in log ponds in the general vicinity of Corvallis, Oreg. Protection against reinfestation ranged from 3 to 6 weeks for DDT, 5 to 10 weeks for heptachlor, and 2 to 6 weeks for malathion. Culex pipiens L. was the dominant species in ponds in June and July; C. stigmatosoma Dyar predominated in August, September, and October. Except in the cooler months from October through May, Culex tarsalis Coq., C. territans Walker, and Culiseta incidens (Thompson) were represented by relatively small percentages.