Evaluation of insecticidal activity of Beauveria bassiana against different instar larvae of Plutella xylostella by using two different methods of application

Plutella xylostella is a globally distributed polyphagous pest of cruciferous crops causing 50 to 80% crop losses annually. The management generally depends on chemical control, however due to occurrence of resistance to major insecticidal groups alternative approaches are inevitable. Microbial control using Entomopathogenic fungi i.e.Beauveria bassiana has potential to suppress the insect population. In the current study 5 serial dilutions of B.bassiana spores were tested by using two different methodologies against 2nd and 3rd instar larvae of P. xylostella. Results revealed that there exists a significant difference between the two methodologies. Direct foliar application causes maximum mortality in both 2nd and 3rd instar larvae. Maximum mean corrected pathogenicity 96.6% was caused by fungal spores when 1 × 108 concentration was sprayed directly on 2nd instar larvae as compared to leaf dip method. In case of third instar larvae also the direct application was most effective induces 70% corrected mortality. This information will help to adopt appropriate method for fungal application in case of insect pest management.