Selection of Optimal Grain Media for the Production of Entomopathogenic Fungi Using Multiple Evaluation Methods

ABSTRACT Entomopathogenic fungi represent a sustainable alternative to chemical pesticides for agricultural pest management. This study evaluated optimal grain media for the mass production of three highly virulent entomopathogenic fungal isolates: Beauveria bassiana 331R and Metarhizium anisopliae SD4‐2 (acaricidal against two‐spotted spider mites), and Purpureocillium lilacinum 44R (insecticidal against green peach aphids). Three grain media—millet, rice, and Italian millet—were assessed based on conidial productivity, virulence, thermotolerance, and UV‐B tolerance. The results demonstrated fungal isolate‐specific optimal combinations with significant media effects on all parameters. B. bassiana 331R achieved the highest productivity on millet (1.76 × 10 9 conidia/g) with complete virulence (100% mortality), P. lilacinum 44R produced maximum yields on millet (4.49 × 10 9 conidia/g), and M. anisopliae SD4‐2 achieved the highest production on rice (5.47 × 10 9 conidia/g) at 14 days post‐inoculation. Environmental stress tolerance showed complex media‐dependent variations: thermotolerance (45°C, 2 h) favored rice for B. bassiana 331R (25.7% germination) and M. anisopliae SD4‐2 (5.7% germination), while P. lilacinum 44R maintained high tolerance across all media (88%–91% germination). A comprehensive evaluation using weighted scoring revealed fungal isolate‐specific optimal media: millet for B. bassiana 331R and P. lilacinum 44R, and rice for M. anisopliae SD4‐2. These findings emphasize the necessity of multi‐parameter evaluation for optimal media selection in commercial production of entomopathogenic fungi, providing crucial insights for developing effective mycoinsecticides.