Virulence of Native Kerala Isolates of Purpureocillium lilacinum against Galleria mellonella Larvae

Abstract

Background:  Crop protection using mycopesticides has a crucial role in sustainable pest management programmes. Biocontrol agents, such as entomopathogenic fungi (EPF) and other microorganisms, offer a safer, more effective alternative to chemical insecticides and pesticides, which are associated with numerous environmental and health risks. Aim: Purpureocillium lilacinum is a well-known entomopathogenic fungus used against a wide range of insect and nematode pests in agricultural ecosystems. In this study, we determined the virulence of four native isolates of P. lilacinum from the soils of Kerala. Study Design: The test organism used was the larval stage of Galleria melonella. The design used was CRD. Place and Duration of Study: Department of Agricultural Entomology, College of Agriculture, KAU, Vellanikkara, Between 2024-2025  Methodology: The mortality of G. melonella larvae was studied at spore concentrations from 1x104 to 1x109 for each isolate in vivo. Result: The isolate TVM1 showed higher mortality (97.50% 7 days after treatment) than other isolates (PKD20-85%, WYD2-92.50%, ALP7-65.00%). The TVM1 isolate showed the highest median lethal concentrations (LC50 and LC90) after 7 days of treatment and the lowest LT50 value, indicating that the strain is virulent towards insect pest. Conclusion: This study has shown that a Kerala native isolate exhibits high virulence against the lepidopteran pest G. melonella.