Evaluation of Chitinase from Metarhizium anisopliae as Biopesticide Against Plutella xylostella

Chitinases are virulence determination factors of entomopathogenic fungi which perform critical functions during degradation of insect cuticle. The present study was conducted to evaluate the biocontrol efficacy of fungal culture filtrate containing chitinase from M. anisopliae against P. xylostella. M anisopliae was cultured by submerged fermentation using colloidal chitin as sole carbon source. Maximum chitinase yield (105.32+/-1.19 mU/ml) was recorded at 96 h of incubation showing the ability of the culture filtrate to hydrolyse the colloidal chitin. Biocontrol assay against P. xylostella showed that the culture filtrates were potent antifeedants by reducing the feeding rate and body weight of the larvae. It reduced the successful pupation and increased larval and pupal mortality in a dosage-dependent manner when applied topically. The highest larval mortalities (67.89+/-3.11 %) were recorded for groups treated with 600 mU ml(-1) chitinase activity. The maximum reduction in cuticular weight (75+/-1.34%) and reduction in chitin content/larva (69+/-2.11) was also observed for the highest chitinase concentration (600 mU ml(-1)) tried. Our results showed that the culture filtrate containing chitinase from M. anisopliae are capable of negatively affecting the growth and metamorphosis of P. xylostella larvae. In view of the need for safer and environmentally friendly pest management tools, the present study can help in the development of enzyme-based biopesticides against P. xylostella.