Co‐inheritance of increased carboxylesterase activity and resistance to organophosphorus insecticides in Myzus persicae (sulzer)

Abstract Levels of carboxylesterase activity and resistance to dimethoate were assessed in F1 clones of Myzus persicae obtained by crossing sexuales from a resistant, high esterase clone (R) with those from three susceptible, low esterase clones. The progeny of the most successful cross fell into two distinct groups, intermediate between the parent clones with respect to both carboxylesterase activity and resistance. The first group averaged 74% of the total carboxylesterase activity, 79% of the esterase band‐4 activity, and 86% of the resistance of R. The second group averaged 43% of the total carboxylesterase activity, 33% of the esterase band‐4 activity and 17% of the resistance of R. The results indicate that R may be heterozygous for two alleles coding for increased esterase levels and associated resistance.