Efficacy of Selected Beauveria and Metarhizium Isolates Against the Common House Fly, Musca domestica L. [Diptera: Muscidae]

The virulence of two Beauveria bassiana (Balsamo-Crivelli) Vuillemin and two Metarhizium spp. (Sorokin) isolates against larval and adult house fly, Musca domestica L. (Diptera: Muscidae), was assessed in the laboratory. Virulence varied significantly among the isolates but insect mortality was independent of route of exposure. Mortality was dose-dependent and stock solutions effected 79-91% and 63-70% mortality within seven days in larval and adult house fly, respectively. Generally, the fungi were more virulent against larvae than adult flies and they all showed good potential as effective biocontrol agents. However, consistently lower median lethal concentration (LC50) and lethal time (LT50) against larval and adult flies showed that M. anisopliae s.s. ARSEF 5471 was the most virulent of the four.