Suitability of agricultural by-products as production medium for spore production by Beauveria bassiana HQ917687

Purpose The seemingly harmful effect of chemical insecticides to the environment, plants and human health, has led to prominent role of entomopathogenic fungi (ENPF) as biopesticide. However, the success of ENPF as biocontrol agent depends on their amenability to easy and cheap mass multiplication. Solid state fermentation (SSF) has emerged as an appropriate technology for management of agro-industrial residues and for their value addition. In this study, the potentiality of agricultural by-products for mass multiplication of Beauveria bassiana was determined. Methods Two sets of SSF experiments with agricultural by-products [tea leaf waste, wheat bran, husk of rice, pigeon pea and urad, and seed cake of jatropha and pongamia] as substrates; one with fortification of nutrients, while other with no nutrient addition were performed. The substrates (200 g) were inoculated with B. bassiana spore suspension (1 9 108 spores/ml) and incubated at 28 C for 14 days. After the incubation period, B. bassiana spore concentrations were enumerated. Results Maximum spore production was observed in rice husk, while jatropha seed cake showed least spore production. Addition of nutrient supplements in the substrates showed slight (pongamia seed cake) to significant (rice husk, tea leaf waste) increase in spore production. The results showed constant increase in spore production with increase in C/N ratio of the substrates. Conclusions Mass production processes directly influences the cost, shelf life, virulence, and field efficacy of fungal pathogens. The results from this investigation are expected to pave the way towards commercialization of B. bassiana by augmenting the research in fungal mass production.