The response of Neoseiulus fallacis (Garman) and Galendromus occidentalis (Nesbitt)(Acari: Phytoseiidae) to six reduced risk insecticides in Canada

Abstract: Laboratory evaluations showed that the response of Galendromus occidentalis(Nesbitt) and Neoseiulus fallacis (Garman) to insecticides were similar only when a compoundwas toxic or totally innocuous to the adults and their availability to lay eggs. Compounds thatwere in between these two extremes showed varied responses. For example, acetamiprid wasmoderately toxic to G. occidentalis adults but only marginally toxic to N. fallacis adults. Itinhibited fecundity considerably in G. occidentalis but had only a slight effect on N. fallacisfecundity. By the same token, thiamethoxam was non-toxic to G. occidentalis adults butmoderately toxic to N. fallacis adults. Its effect on fecundity was marginal for both species.Therefore, acetamiprid, thimathoxam, spinosad, and thiacloprid should be evaluated in the fieldbefore they are considered in IPM programs. In contrast, imidacloprid was too toxic for furtherfield testing and methoxyfenozide was totally harmless and can be included in IPM programswithout additional field testing.