关键词: 松墨天牛, 金龟子绿僵菌, 菌株筛选, 产孢量, 发芽率, 致病力

Abstract:

Monochamus alternatus is the major vector of pinewood nematode disease，Bursaphelenchus xylopilus. Ten strains of Metarhizium anisopliae, of which six isolated from M. alternatus, and four from Anoplophora glabripennis, Pachynematus itoi, Galleria mellonella and a burrower bug (Cydnidae) at different locations, were tested for the sporogenous ability and spore germination rate. Three strains of M. anisopliae (1291, 1349, and 2049) were selected, and their virulences to M. alternatus and G. mellonella larvae were assayed using the adult-conidial attaching method (attaching all tarsi of adult with dry conidial) and larva dip method with Beauveria bassiana strain F-263 as the control. The results indicated that the three strains of M. anisopliae, especially the strain 2049, were highly virulent to M. alternatus, with the cadaver rates as high as 76.9%-93.1% (1×10⁷ conidia/mL) and 57.9%-75.0% (6.5×10⁵ -3.4×10⁶ conidia/individual) for larvae 15 d after inoculation and adults 20 d after inoculation respectively; as contrast, the cadaver rates by the B. bassiana strain F-263 was 96.3 % (1×10⁷ conidia/mL) and 55.0% (9.7×10⁵ conidia/individual) for adults and larvae, respectively. However, the virulence of the three strains of M. anisopliae to G. mellonella larvae was rather low, and this suggested that  they were strong　host specific. The three strains may serve as a potential source of biocontrol agents for M. alternatus.
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Key words: Monochamus alternatus, Metarhizium anisopliae;strain selection； sporogenous ability, spore germination rate, pathogenicity