斜纹夜蛾高致病力生防真菌的筛选与鉴定

Screening and Identification of Biocontrol Fungus with High Pathogenicity against Spodoptera litura

本研究从斜纹夜蛾幼虫僵虫中分离并纯化虫生真菌,得到6株昆虫病原真菌,利用形态学和分子生物学方法对上述真菌进行鉴定,采用浸渍法测定6株真菌对斜纹夜蛾2龄幼虫的毒力。结果表明,6株虫生真菌分别为2株球孢白僵菌Beauveria bassiana,以及莱氏绿僵菌Metarhizium rileyi,木贼镰刀菌Fusarium equiseti,曲霉菌Aspergillus nomiae和糙孢蓝状菌Talaromyces trachyspermus各1株。在1×10^(8)个孢子/m L浓度下,LT50分别为4.737 d,4.543 d,1.343 d,2.086 d,2.212 d和2.351 d,6株虫生真菌对斜纹夜蛾2龄幼虫均表现出较强致病力,其中莱氏绿僵菌表现最好。本研究首次报道了镰刀菌和曲霉菌能够感染斜纹夜蛾,并首次发现糙孢蓝状菌能够感染昆虫。

Six strains of entomogenous fungi were isolated and purified from muscardine cadavers of Spodoptera litura larvae,and were identified by morphological and molecular biological methods.The pathogenicity of these strains against S.litura larvae was determined by the dipping method.The six fungal strains were identified as Beauveria bassiana(two strains),Metarhizium rileyi,Fusarium equiseti,Aspergillus nomiae,and Talaromyces trachyspermus,whose LT50 against the pest larvae were 4.737,4.543,1.343,2.086,2.212,and 2.351 days,respectively.All the six strains of entomogenous fungi showed high pathogenicity against the pests at the concentration of 10^(8) conidia/mL,in which M.rileyi established the highest pathogenicity.The present study reports for the first time that S.litura can be infected by F.equiseti and A.nomiae and that T.trachyspermus is able to infect insects.