Antifungal activity of non-volatile metabolites from entomopathogenic fungi against the foliar pathogens Drechslera bicolour

Abstract

The present study investigated the antagonistic efficacy of non-volatile secondary metabolites produced by five fungal bioagents (Beauveria bassiana, Nomuraea rileyi, Metarhizium anisopliae, Verticillium lecanii, and Trichoderma viride) against the fungal foliar pathogen Drechslera bicolor in an in-vitro assay. Culture filtrates of the bioagents were incorporated into PDA medium at three concentrations: 10%, 25%, and 50%. All effective treatments showed statistically significant and concentration-dependent inhibition of D. bicolor linear growth after seven days (168 hrs). Beauveria bassiana was the most potent antagonist across all dilutions, achieving the highest inhibition of 55.64% at the 50% concentration (39.93 mm growth). N. rileyi (38.82% inhibition) and M. anisopliae (37.07% inhibition) demonstrated moderate, comparable levels of antagonism at 50%. T. viride exhibited the lowest biological activity (16.18%). Crucially, V. lecanii was completely ineffective at all tested concentrations, recording 0.00% inhibition, performing at par with the uninhibited control (90.00 mm growth). These findings highlight the strong fungistatic potential of B. bassiana metabolites against D. bicolor, underscoring its promise in developing natural biofungicides.