Diamondback Moth Resistance to Diazinon and Methomyl in Taiwan12

Abstract

Diazinon- and methomyl-resistant strains of Plutella xylostella (L.) with resistance ratios of 14.4 and 175, respectively, were developed in the laboratory by continuous selection for 14 and 19 generations. The susceptibility to these 2 chemicals of this insect pest at several locations in Taiwan from 1975–77 was determined. This survey confirms the development of resistance to these insecticides in some field populations of the diamondback moth. Electrophoretic studies revealed qualitative differences in esterase and phosphatase zymograms in susceptible and resistant strains.