Study On The Control Of Brontispa Longissima With Metarhizium Anisopliae

Brontispa longissima originating from the Pacific islands, was a invasive pest in china. It was very dangerous and devastating for the palm plants. This paper is to research the control of B.longissima with Metarhizium anisopliae. It include the isolation and select of M.anisopliae; The infection of different instars and host plants to the pathogenicity of dominat isotates; its compatibility to chemical pesticide; the relationship between infection by M.anisopliae and parasitism by Asecodes hispinamm showed that the efficiency in controlling B.longissima; the effect of B.longissima control with M.anisopliae by different measures in fields. The following are the investigation results:(1) Seven strains of M. anisopliae were selected for bioassay against larvae of B.longissima. There were some different among seven strains in biological characters. There are were no significant different in the mycelia growth in media SDAY but Mhu was expected. There were significant different in the sporulation yields, germination velocity and germination rate. The pathogenicity of strains Mhu and M09 to fourth instar of B.longissima is very high, and the mortalities are higher than 90% afer 15 days of treatment. These characters of the fungus are consistent to some extent, the dominant isolate M09 and Mhu were selected to study in stability through being successionally cultured in five generations. The result showed that M09 was better than Mhu.(2) The isolate M09 was bioassayed for its virulence toward B.longissima inoculated with suspensions of 10⁴,10⁵,10⁶,10⁷ and 10⁸ conidia/ml. The resulting data were well fitted to time-dose-mortality model, yielding estimates of parameters for time and dose effects of each isolate. The mortality of B. longissima had a positive relationship with time and conentration of supensions, it increased with time and the concentration. The same concentration against different instars indicated that the mortality was more powerful to younger instars than fifth instars and adults. Host plant influenced the virulence of M. anisopliae, it was Livistona chinensis > Roystonea regia > Revenea rivularis > Cocos nucifera. LT₅₀ values depend on both of the host plants and concentrations.