Analysis of Biodegradation of the Synthetic Pyrethroid Cypermethrin by Beauveria bassiana

Entomopathogenic fungi like Beauveria bassiana play a crucial role in natural control of arthropod pests which are being used in Integrated Pest Management programs. Assessing the compatibility of biological and chemical counterparts used in IPM programs is essential to achieve successful results in pest management. Behavior of four isolates of B. bassiana (ITCC 913, ARSEF 2860, ARSEF 1166, and ARSEF 3041) was tested in the presence of the pyrethroid insecticide cypermethrin. Spore germination and growth bioassays were conducted to assess the impact of cypermethrin on germination and growth. Though growth was not totally inhibited, there was retardation in the germination of spores and growth of the mycelium. Under this condition, ITCC 913 showed highest tolerance toward cypermethrin. Further analysis of the culture crude extracts by GC-MS revealed degradation of the insecticide by B. bassiana and putative intermediates of the degradation pathway were identified. This study reveals the potential of the entomopathogen B. bassiana in degradation of the pyrethroid insecticide cypermethrin. In conclusion, this potentiality of the studied fungus may help in the IPM strategies and find its role in degradation of such chemical pesticide compounds for utilization as a biodegradation agent further.