Assessment of different growth substrates for the viability of Beauveria bassiana

Entomopathogenic fungi are a diverse group of fungi that have the special ability to infect and kill insects. Beauveria bassiana, a widely studied entomopathogenic fungus, has shown promise as a biocontrol agent against various insect pests. However, its  efficacy can be influenced by environmental factors, including the growth substrate. This study evaluated the viability of B. bassiana on different solid media (rice, wheat, gram, pigeon pea, vermicompost, and Corcyra rearing waste) and liquid media (Potato Dextrose Broth and Sabouraud Dextrose Broth) for the viability of the fungus. The results indicated that rice recorded the highest mean colony forming units (cfu) at 60 days of storage (86.33×107 cfu/ml), and an increase in mean cfu was observed from 30 to 60 days of storage, gradually decreasing to 22.68 at 150 days of storage. Other solid substrates, including wheat, gram, and pigeon pea, showed significantly lower viability, with vermicompost exhibiting the least support for fungal growth. Among liquid substrates, Sabouraud’s Dextrose Broth (SDB) and Potato Dextrose Broth (PDB) demonstrated superior performance, with initial colony forming units values of 77.11 and 73.42, respectively, which declined over time. The findings suggest that rice among solid substrates and SDB among liquid substrates are optimal choices for sustaining B. bassiana viability for extended periods.