Abstract: During 1988-1990, appropriate wetting agents and additives were selected and mixed with pure spore powder of Beauveria bassiana in the laboratory and workshop trial productions in the development of wettable powder formulation of the entomopathogenic fungus. Two formulations were obtained with the following properties: Forming uniformed wettable suspension with in 3 minutes, 98% of the particles passing a 325 mash, over 85% of germinating rate of the spores, and 8 months of storage life under 10-20°C laboratory conditions with 85% spore germinating rate, which was not significantly different from that of the pure spore powder. A 95% killing effect against the Asian corn borer, Ostrinia furnacalis was obtained in the laboratory with the wettable powder containing 50×10⁹ spores/g, with LC₅₀=7.30×10⁵ spores/ml, LT₅₀=113.6 hr.. In the field application trials against the Asian corn borer larvae, an over 80% control effect was achieved.