BIOCHEMICAL-MECHANISMS OF AZINPHOSMETHYL RESISTANCE IN THE TUFTED APPLE BUD MOTH PLATYNOTA-IDAEUSALIS

Potential mechanisms of resistance to azinphosmethyl, an organophospha te insecticide, were examined in five field populations of the tufted apple bud moth Platynota idaeusalis (Walker). Adult male moths from re sistant and susceptible populations were collected on sex pheromone tr aps and analyzed for glutathione transferase, general carboxylesterase , and cytochrome P-450 monooxygenase activity. Kinetics and inhibition profiles for acetylcholinesterase were also compared among population s. Significant intra- and interpopulation variation was demonstrated i n these detoxification enzyme systems, but no resistance correlation w as found to carboxylesterases, cytochrome P-450 monooxygenases, or glu tathione transferase using the substrate 1-chloro-2,4-dinitrobenzene o r for acetylcholinesterase activity. However, elevated glutathione tra nsferase activity toward the model substrate 1,2-dichloro-4-nitrobenze ne was consistently associated with azinphosmethyl resistance. (C) 199 5 Academic Press, Inc.