Selective Isolation of the Entomopathogenic Fungi Beauveria bassiana and Metarhizium anisopliae from an Artificial Potting Medium

A basal medium consisting of oatmeal agar was superior to seven other media for isolation of Metarhizium anisopliae and Beauveria bassiana from an artificial potting medium. A rate of 0.55 g/l of dodine and 5 mg/l of chlortetracycline allowed optimum recovery of B. bassiana alone. Decreasing the amount of dodine to 0.46 g/l and adding 0.38 g benomyl allowed recovery of both entomopathogens at high frequencies in the absence of most other fungi. Addition of 10 mg/l crystal violet aided in visibility of the target fungi without affecting recovery frequencies. Exposure of culture plates to as little as 2 @m01 m^-2s^-1 light delayed observation of colonies of both entomopathogens up to 7 days compared to cultures incubated in the dark.