Abstract:

Monochamus alternatus is a major insect vector transmitting pinewood nematode disease，an important quarantine disease of pine forests. In this paper，the muscardine cadavers of M. alternatus adults died by Metarhizium anisopliae were put in the forest floor，and the dynamics of spores on the cadaver in natural status was studied. The knowledge would provide a theoretic basis for M. alternatuss biocontrolling using M. anisopliae as an agent. In the two-years experiment，the amount of spores on the cadaver decreased significantly in the first 42 days，and then decreased slightly. The amount of spores on the cadaver was maintained at the level of 10⁵ spores per adult from the 84th days to the end of the experiment. Spore germination rates were always above 90% within 126 days. Then the virulence of M.anisopliae to M. alternatus was tested in different time， and the difference of the virulence between the spores and the control was not significant when M. alternatus inoculated with 10⁷or 10⁶ spores·mL^-1. The results showed that spores on the cadaver could keep high virulence to M.alternatus for a long time in field.

Key words: Metarhizium anisopliae, Monochamus alternatus, muscardine cadavers, pathogenicity, survival in the forest, dynamic