Variations in Insecticide Susceptibility of the Predatory Mite, Amblyseius womersleyi SCHICHA (Acarina: Phytoseiidae), in the Tea Fields of Japan

Abstract

Insecticide susceptibility of the predatory mite Amblyseius womersleyi SHICHA in tea fields was studied using three types of pesticides: organophosphate, carbamate and some synthetic pyrethroids. Of the 20 populations tested, the Hiranuma-1 and the Ide-1 populations collected from eastern Shizuoka Prefecture were resistant to methidathion, methomyl and permethrin (W.P. formulation). The Hiranuma-1 population also showed survival of cypermethrin, and fluvalinate. Mortality of this population differed between two types of permethrin formulation. Emulsifiable concentrations of permethrin were more toxic than wettable powder formulation.