Evaluation of Pathogenicity of the Fungi and in Hazelnut Weevil ( L., Coleoptera, Curculionidae) Larvae.

The nut weevil () is one of the most important and widespread pests in hazelnut orchards. In order to screen entomopathogenic fungal strains with high virulence against , the growth rate, sporulation, and cumulative mortality of different and strains were investigated, and the process by which CoM 02 infects larvae was observed using scanning electron microscopy. The results indicated that the growth rate and sporulation of different fungal strains significantly differed. Thirteen days after inoculation with CoM 02, the cumulative mortality of larvae reached 100 %, which was considerably higher than that of the other five strains. As the most virulent of the six test strains, the cadaver rate, LT, and LT of CoM 02 were 93.4 %, 7.05 and 11.90 days, respectively. Analysis of the infection process by scanning electron microscopy showed that the spore attachment, hyphal germination, hyphal rapid growth, and sporulation of CoM 02 occurred on the 3rd, 5th, 7th, and 11th day after inoculation, respectively, indicating that the infection cycle takes approximately 11 days. This finding suggests that the highly virulent plays an important role in the biocontrol of in China.