Comparative evaluation of five Beauveria isolates for housefly (Musca domestica L.) control and growth optimization of selected strain.

Pathogenic potential of five native Beauveria isolates was assessed against housefly adult and larvae in laboratory bioassays. Beauveria isolate Beauveria bassiana HQ917687 showed highest virulence with 72.3 and 100 % mortality of larvae and adults of Musca domestica, respectively. Other Beauveria isolates caused 36-52 % housefly larval mortality while the adult mortalities varied between 72 and 82 %. B. bassiana HQ917687 also showed the fastest killing activity with LT(50) of 4 days (for larvae) and 3 days (for adults). This isolate showing highest virulence was selected for its growth optimization in terms of biomass and spore production using response surface methodology. The optimum value of temperature, yeast extract, and pH for maximum biomass and spore production was predicted as 27 °C, 5.00 g/l, and 6.75, respectively. Temperature was found to be the most critical factor influencing biomass and spore yield of the fungus and even nullified the effects of other factors at sufficiently higher value. The results obtained in this study depict the significance of appropriate strain selection and process parameter optimization in order to facilitate mass production of biocontrol agents.