Dosage-Mortality Responses of the Parasite, Lixophaga diatraeae, to Selected Insecticides in the Laboratory123

Abstract

A topical application technique was used to evaluate dosage-mortality responses of a tachinid parasite, Lixophaga diatraeae (Townsend), to 6 insecticides. Males were significantly more susceptible to azinphosmethyl than were mated females. Differences in LD50S between males and unmated females and between unmated and mated females were not significant. Furthermore, the response to this insecticide by 2- and 6-day-old parasites was not significantly different. Monocrotophos and diazinon were the most toxic compounds applied to 6-day-old males and mated females, followed by carbofuran and endrin, while azinphosmethyl and carbaryl were the least toxic. Males from a Louisiana population were significantly more susceptible to topical applications of endrin and azinphosmethyl than were males of the same age from a Trinidad population. No significant difference was detected in susceptibility to endrin between 6-day-old mated females from a Louisiana population and a Trinidad population. However, females from the Louisiana population were significantly more susceptible to azinphosmethyl than were comparable females from the Trinidad population.