Toxicity of Several Insecticide Formulations Against Adult German Cockroaches (Dictyoptera: Blattellidae)

Abstract

Toxicity of bendiocarb, chlorpyrifos, cyfluthrin, cypermethrin, fenvalerate, hydramethylnon, malathion, propetamphos, propoxur, and pyrethrins against the adult German cockroaches, Blattella germanica (L.), was investigated. At LD50, cyfluthrin was the most toxic insecticide to adult males (0.53 /log/g), adult females (1.2 /log/g), and gravid females (0.85 Ilg/g). Malathion was the least toxic insecticide to adult males (464.83 Ilg/g), adult females (335.83 /log/g), and gravid females (275.90 p.g/g). Males and gravid females were generally more sensitive than non gravid females to the insecticides that we tested. In tests with malathion, however, males were more tolerant. The order of toxicity of the insecticide classes varied among the stages of adult German cockroaches. The order of toxicity for males and non gravid females was pyrethroids > pyrethrins = oregano phosphates (except malathion) > carbamates = amidinohydrazone. The order of toxicity for gravid females was pyrethroids > pyrethrins = oregano phosphates (except malathion) > carbamates > amidinohydrazone. These differences in toxicity suggest that sex differences should be considered when determining insecticide toxicity for German cockroaches.