Effect of physical and nutritional conditions such as culture temperature, pH, light, and culture and substrate medium with supplements were assessed for vegetative growth and production of conidia, in addition to virulence against Lepidoptera and Coleoptera pests by strains of Beauveria sp. Dextrose, peptone, and yeast agar with wheat bran or amaranth flour, 23 to 25°C, 7.5-8.5 pH, and obscure light were optimum for radial growth. Light and pH for most production of conidia depended on the fungal strain. Most conidia per gram were produced with 4% amaranth added to oat grain and culture in dextrose, peptone, and yeast broth with 2% wheat bran. Both fungal strains killed 91.1-96.0% of Phyllophaga sp. (Coleoptera: Scarabaeidae) and Spodoptera exigua Hübner and Trichoplusia ni Hübner (Lepidoptera: Noctuidae). Results confirmed the possibility of increased production of B. bassiana conidia by protein supplements and physical growing conditions to maintain pathogenicity.