Abstract: Metarhizium spp. are very important entomogenous fungi for the biocontrol of soil insects. In order to clarify the repellent effect of Metarhizium spp. against wireworms, we tested the behavioral responses of Melanotus cribricollis wireworm towards the conidium, volatiles and nonvolatiles of Metarhizium pingshaense WP08 using Ytube olfactory bioassay in the present study. The results showed that when the concentration of M. pingshaense WP08 conidium was 5×10⁸ conidia·g^-1 dry soil, wireworms were repellent significantly by the conidium (P<0.001), and the repellency was weakened with the decrease of conidium concentration in the soil. There was no repellency against the wireworms when the conidium concentration was 5×10⁶ conidia·g^-1 dry soil. The fermentation broth of M. pingshaense WP08 conidium (1×10⁸ conidia·mL^-1) showed significant repellency against the wireworms (P<0.001), while the VOCs emitted from M. pingshaense showed no significant repellency against wireworms (P>0.05). Our results provide important basic information of chemical mechanism of fungirepellency against insects.

Key words: larch caterpillar, population quantity, Great Xing’an Mountains, relative weight, meteorological factors