Bioactive volatile organic compounds from diverse Metarhizium anisopliae isolates: GC–MS/MS analysis and insecticidal potential against Spodoptera litura

This study delves into exploring the insecticidal potential of various isolates of Metarhizium anisopliae by documenting and analyzing their volatile secondary metabolites. The primary objective was to identify isolates showcasing promising biocontrol properties, thereby emphasizing sustainable alternatives to synthetic pesticides. Twelve isolates of M. anisopliae were subjected to examination, with GC-MS/MS analysis utilized for the identification of volatile organic compounds. Laboratory bioassays were conducted against Spodoptera litura, with recorded mortality rates serving as indicators of effectiveness for each isolate. A central focus of investigation was the correlation between the number of volatile metabolites and insecticidal activity. Results indicated that among the isolates, UASR BC-Ma38 exhibited the highest percentage of mortality (98.89 per cent) in bioassays against S. litura, which correlated with the presence of 28 volatile metabolites, primarily demonstrating insecticidal activity. Conversely, ICAR-NBAIR-Ma14 displayed the lowest mortality percentage (45.56 per cent), along with 14 identified metabolites. In conclusion, the study underscores the efficacy of certain M. anisopliae isolates, particularly UASR BC-Ma38, as potential biological control agents against S. litura. Moreover, the correlation between the abundance of volatile metabolites and insecticidal activity highlights the significance of these compounds in augmenting the virulence of isolates, thereby contributing to the development of sustainable pest management strategies leveraging entomopathogenic fungi.