Attraction of Myzus persicae (Hemiptera: Aphididae) to microbial volatiles emitted from the entomopathogenic fungus Beauveria bassiana

Microbial volatile organic compounds (MVOCs) mediate behavioral responses in insects. MVOCs emitted from the entomopathogenic fungus Beauveria bassiana function as attractants or repellents depending on the species of insect. We conducted a series of experiments to assess the behavioral response of Myzus persicae to MVOCs emitted by B. bassiana. Time-course behavioral responses of apterous and alate M. persicae to B. bassiana mycelium and conidia were assessed using still-air and Y-tube bioassays. Results from still-air and Y-tube bioassays determined that M. persicae was preferentially attracted to mycelium and conidia of B. bassiana. Alate and apterous M. persicae were attracted more within 5 to 10 mins interval of time to mycelium of B. bassiana. We tested different concentrations of conidia. The higher concentration (10⁷, 10⁶ conidia/ml) showed significant increase in the responses of aphids over different intervals of time. However, the lower concentration (10⁵, 10⁴ conidia/ml) showed random responses of aphids to conidia of B. bassiana in both the bioassays. Mortality of M. persicae occurred due to the attraction of M. persicae to B. bassiana during the still-air bioassays. Emission of following MVOCs were confirmed from mycelium of B. bassiana using SPME-GC-MS: 3-methyl-1-butanol, 2-methyl-1-butanol, 1-octen-3-ol, 2-octenal, methyl benzoate, and methyl cinnamate. Subsequent experiments will be conducted to characterize the behavioral and electroantennogram responses of M. persicae to these MVOCs. Enhancing the attraction of M. persicae to B. bassiana could improve the efficacy of entomopathogenic fungus as part of microbial control tactics in IPM systems.