Scanning electron microscopic studies of Beauveria bassiana against Lipaphis erysimi Kalt

Abstract

This work was aimed to identify the LC50 of the indigenous fungal isolates for controlling L. erysimi infesta-tion in mustard aphid besides to probe the mechanism of action of the local isolates and comparison of the efficacy with the reference culture and commercial formulation ‘Mycojaal’. Three isolates of entomopathogenic fungi Beauveria bassiana were tested for infection on nymph of Lipaphis erysimi Kalt. using scanning electron microscopy (SEM) to record any variation. The SEM revealed adhesion of spores of B.bassiana followed by penetration of L.erysimi nymph surface. It was observed that all Beauveria isolates showed little variation with respect to penetration and adhesion at different time intervals. Further, lethal concentration (LC50) values of B. bassiana isolates against L. erysimi was recorded and was lowest (0.05x107 spores/ml) in B. bassiana MTCC 4495 and highest (0.11.X107 spores/ml) was recorded in native isolate F10 after 120 hours of treatment. The study has established the need for the isolation and evaluation of the indigenous Beauveria isolate. Moreover, it also exhibited the efficacy of the reference and commercially available biocontrol agents.