Use of Microbes for Control of Monochamus alternatus, Vector of the Invasive Pinewood Nematode

Abstract

Pine wilt disease, the most serious problem in pine forests in Asia, is caused by the pinewood nematode, Bursaphelenchus xylophilus. This nematode is an invasive pest in Asia where it is vectored by adults of a native wood boring cerambycid, Monochamus alternatus, during their maturation feeding. Surveys of pathogens were carried out to develop microbial control of this insect, and a strain of Beauveria bassiana highly virulent to M. alternatus was selected for development. Since larvae of M. alternatus live under the bark of pine trees, they were rarely being infected with conidia applied on the outside of the bark. A band-formulation of the fungus using nonwoven material was developed to maintain conidia at a high density, and larval mortalities were improved when using this formulation. Effective control of pine wilt disease also entails preventing feeding by M. alternatus adults on pine twigs, thereby avoiding transmission of the pinewood nematode. It takes 10–15 days for band-formulations of B. bassiana to kill emerged adults of M. alternatus. However, since infected adults are very immobile and seldom feed on pine twigs, their effective transmission of B. xylophilus is very limited.