Mechanisms of Resistance of the Adult Housefly (Musca domestica) to ‘Cyclodiene’ Insecticides

EXPERIMENTS have been conducted with isodrin and endrin labelled with carbon-14 in the terminal unchlorinated ring1 and with aldrin and dieldrin labelled in the chlorinated ring (from the Radiochemical Centre, Amersham). Adult insects used were of a susceptible strain (S) and dieldrin-resistant strains (R 1) and (R 2). R 1 arose from the S-strain by exposure of the larvae to dieldrin and R 2 from R 1 by removal of the dieldrin pressure after 19 generations2.