Suspected Insecticide Resistance Mechanism in the Peach–Potato Aphid

Abstract

POPULATIONS of the peach–potato aphid, Myzus persicae (Sulzer), that have survived exposure to organophosphorus insecticides are sometimes received for identification in the British Museum (Natural History). Microscopical examination reveals that resistant populations have better developed lateral abdominal tubercles on segments 2–4 than susceptible populations. The resistance of Myzus persicae to demeton-methyl is not stable, a twenty-five-fold resistance being acquired during seven clonal generations exposed to it and lost during thirty generations not exposed¹. Experiments being done at Rothamsted Experimental Station (C. J. B., in preparation) made it possible to study the morphology of aphids from susceptible and resistant aphid populations and to compare them with each other and with susceptible members of a previously resistant population.