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Beauveria Bassiana: Entomopathogenic Fungi as Biopesticide Reported from Cachar, Southern Assam

Ankita Dey*, Baby Singha

Several attempts yielded that soils of Cachar district are rich in entomopathogens viz., Entomopathogenic Nematodes (EPN), Entomopathogenic Bacteria (EPB) and Entomopathogenic Fungi (EPF), therefore adequate knowledge of pathogen ecology- its spatial distribution, population dynamics and its efficacy is essential for improvement of sustainable, eco-friendly pest management practice in the district. Among all the entomopathogens, EPF are the most potential natural mortality agents because it has wide host range, host specific, viability in soil and infectivity on slight contact with the host. The present study was conducted to isolate and identify local strain of EPF from soil using Greater wax moth, Galleria mellonela as baiting insect. Based on detailed morphological study through microscopic observation after lactophenol cotton blue staining, the species identified as Beauvaria bassiana. In Potato Dextrose Agar (PDA) culture medium EPF was cultured at various pH levels (3.5-6.8) for 13 days. The identified EPF, B. bassiana grew as white mould, it produces distinct spore balls made of many dry, powdery conidia. Each spore ball is made of group of numerous conidiogenous cells. The conidiogenous cells are short, ovoid and with elongated rachis. The optimum temperature, relative humidity and pH for abundant sporulation growth of EPF, B. bassiana in PDA culture medium were 25°C, 90 ± 5% and 6.8 respectively. Sporulation growth directly proportional to pH level, as with the increase in pH the biomass of B. bassiana increased considerably. Maximum dry biomass growth recorded 180 mg and radial expansion 4.57 mm diameter at pH 6.8. PDA media also noted to be ideal for mass production of B. bassiana.