Toxicity of Fifteen Organophosphorus Insecticides to Several Insect Species and to Rats1

Abstract

The LD50 of 15 organophosphates as [mu]g/g is reported for German cockroaches, pea aphids, black carpet beetle larvae, armyworm larvae, houseflies and white rats and as ppm in solution for mosquito larvae. The pea aphids were the most generally susceptible and the black carpet beetle larvae the most generally resistant. Malathion displayed the highest desirable toxicity ratio between insects and rats, while schradan was the most selectively toxic to rats. Because of its general toxicity, para-oxon was further studied with 21 other spp. of insects and the LD50 values found to vary 50-fold among these insects.