Insecticide effects onEntomophthora muscae [Zygomycetes: Entomophthorales]

Abstract

Studies were conducted to determine the effect of insecticide residues on germination of primary conidia of Entomophthora muscae (Cob.n) Fresenius and to determine the relative susceptibility of h~althy and infected Musca domestica L. to insecticides. Primary conidia were discharged from M. domestica cadavers onto glass microscope slides treated with insecticides. All insecticides significantly inhibited germination relative to control slides. Permethrin and haled had the least inhibition (36-40 96 ), while malathion and dimethoate almost completely inhibited germination (87-94 % ). Tetrachlorvinphos/dichlorvos and carbaryl were intermediate (57-59 %). Healthy flies were not significantly different from infected flies in terms of susceptibility to haled, dimethoate, or permethrin. Infected flies exposed on the last day of pathogen incubation died on the bottom of the Petri dishes, rather than climbing and attaching as did untreated, infected flies. Both control and treated groups produced large numbers of primary conidia.