Isolation, Identification, Biological Characterization, and Pathogenicity of Entomopathogenic Fungus from the Larvae of the Evergestis extimalis (Scopoli) (Lepidoptera: Pyralidae)

At Qinghai agriculture districts, <i>Evergestis extimalis</i> poses a significant threat to spring rapeseed cultivation through its larvae burring into the rapeseed kernels and feeding seeds. To protect the ecological environment of the Qinghai-Tibet Plateau, it is essential to research and develop biological control technologies for pest management. In this study, we isolated and purified a new entomopathogenic fungus from the carcasses of <i>E. extimalis</i> larvae, which was identified as <i>Mucor hiemalis</i> based on morphological characteristics combined with ITS rDNA and 18S rDNA sequence analyses. Subsequently, the optimal growth conditions for the strain were determined as follows: SDAY medium, fructose as the carbon source, peptone as the nitrogen source, 25 °C, pH 6.0-7.0, and a 0:24 (light:dark) photoperiod.However, UV can significantly reduce fungal spore production. The bioassay result shows its pathogenicity was a concentration-dependent effect on <i>E. extimalis</i>, and younger larvae were more susceptible. With 1 × 10⁸ spores/mL inoculated, survival of second instar larvae decreased by the greenhouse pot experiment. In conclusion, <i>M. hiemalis</i> exhibits a significant biocontrol potential against <i>E. extimalis</i>.