The research aimed to isolate entomo-patho-genic fungus B. bassiana and describe pheno-typic characters in colony morphology as well as measure the growth rate from several natural habitats such as the leaf surface, soil and including larval insect Spodoptera litura and Helicoverpa armigera. The research was done in Kepanjen, Malang from July to October 2000. Purposive random sampling method was used for data gathering. The result showed that B. bassiana isolate managed to be isolated from the three natural habitats involving larva S. litura and H. armigera, the soil, and surface of tomato leaves. B bassiana isolate of insect habitat represented phenotype in colony morphology with curved character, while isolate of the leaves surface and soil indicated phenotype in colony morphology with raised and bowl-shaped character. Isolate of insect with curved colony character represented higher growth rate than that of the leaves surface or the soil with raised and bowl-shaped colony character. Thus, B. bassiana isolate with the curved colony of insect served as an isolate which was expected to be virulent as controlling agent to biological elements. This reseach approve that curve phenotype character in colony morphology can be used as virulence estimation in B. bassiana.