Relative toxicity of some acaricides to the predatory mite, Amblyseius womersleyi and the twospotted spider mite, Tetranychus urticae (Acari: Phytoseiidae, Tetranychidae)

Abstract

The relative toxicity of some acaricides to the predatory mite, Amblyseius womersleyi and the twospotted spider mite, Tetranychus urticae was evaluated in the laboratory. Bifenazate, acequinocyl and flufenoxuron, were much less toxic to adult females and immatures of A. womersleyi than to those of T. urticae, and egg production of adult female predators treated with these three acaricides was 70-91% that of control females. Etoxazole and chlorfenapyr did not seriously affect the survival and reproduction of adult female predators but caused high mortality rates in eggs and larvae of A. womersleyi. Azocyclotin, milbemectin and fenazaquin were very toxic to adult females and immatures of A. womersleyi. Adult female predators survived on a diet of spider mites treated with bifenazate, acequinocyl and flufenoxuron, and their fecundity was not substantially affected. The results indicate that bifenazate, acequinocyl and flufenoxuron are promising candidates for use in integrated mite management programs where A. womersleyi is the major natural enemy.