Effect of Fungal Infection on Defence Proteins of <i>Musca domestica L.</i> and Variation of Virulence with Temperature

Abstract

With the current global drive for alternative control measures that are safer in comparison to synthetic insecticides, it was considered necessary to assess some fungal entomopathogens for efficacy against the house fly, Musca domestica. The effect of fungal infection on activity of two detoxification enzymes (esterase [EST] and glutathione-S-transferase [GST]) was determined in the laboratory. Effect of temperature on progression of mycosis was also investigated between 15 and 35℃ to determine the optimum temperature necessary for successful fungal infection. Two Beauveria bassiana strains (ARSEF 1564 and ARSEF 8891), Metarhizium robertsii (ARSEF 1057) and M. anisopliae s.s. (ARSEF 5471) were evaluated in this study as potential sources of mycoinsecticide formulations. The fungal strains infected larval and adult house flies successfully by inhibiting activity of EST and GST with a concomitant insect mortality of > 90%. A significantly higher number of dead specimens (80-100%) had fungal growth between 20 and 25℃ with a noticeable level of mycosis also at 30℃. The evaluated fungal strains showed good insecticidal efficacy and could,  therefore, serve as good sources of mycoinsecticide formulations against house fly. If this area of biological control is well explored it would reduce reliance on synthetic insecticide formulations.

Keywords: Defence proteins, house fly mortality, mycosis, optimum temperature