Scanning electron microscopic studies of Beauveria bassiana against Lipaphis erysimi Kalt

Abstract

This work was aimed to identify the LC 50 of the indigenous fungal isolates for controlling L. erysimi infestation 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 (LC 50 ) values of B.bassiana isolates against L. erysimi was recorded and was lowest (0.05x10 7 spores/ml) in B. bassiana MTCC 4495 and highest (0.11.X10 7 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.

Evaluate the Effects of Entomopathogenic Fungi Isolates on Wheat Aphid, Schizaphis graminum (Rondani) (Hemiptera: Aphididae)

“…S. graminum infected by P. neoaphidis showing hyphal bodies emerged through the host cuticle. Also, Sharma et al (2017) Tested three isolates of entomopathogenic fungi Beauveria bassiana infected nymph of Lipaphis erysimi Kalt. using scanning electron microscopy (SEM) to record any variation.…”

Deciphering the Relationships Among Enzymatic Systems and Virulence of <em>Beauveria bassiana</em>: A Review

“…Unlike bacteria or viruses, B. bassiana infect insects by direct penetration of the cuticle. However, insect cuticle serves as a physical barrier against fungal attack; it is a structure formed by crystalline chitin nanofibers inside proteins, polyphenols, and lipids matrix (Vincent and Wegst 2004;Sharma et al, 2017). So, B. bassiana secretes several extracellular cuticle degrading enzymes (CDEs) such as proteases, chitinases, and lipases to degrade the major constituents of the insect's cuticle and allow hyphal penetration into the insect's cuticle (Dhawan and Joshi 2017).…”