一株咖啡灭字脊虎天牛幼虫虫生真菌鉴定、培养及致病力研究

The Identification,Cultivation and Pathogenicity of an Entomogenous Fungus in Larvae of Xylotrechus quadripes Chevrolat

为探索防治咖啡灭字脊虎天牛的生物菌剂,从田间自然罹病死亡的咖啡灭字脊虎天牛幼虫的僵虫虫体上分离到1株对其有高致病力的虫生真菌(编号Bd01),生测实验发现该菌对咖啡灭字脊虎天牛幼虫的LC为4.56×10^(5)孢子/mL。采用形态学观察和ITS序列分析对该菌进行鉴定,并测试不同环境因子对该菌营养生长和致病力的影响。结果显示:该菌为爪哇虫草,PPDA为该菌最适生长培养基,26℃、85%~100%的相对湿度是其最适宜的生长条件,紫外光照射30 min后不利于该菌生长;1×10^(8)孢子/mL孢子悬浮液接种咖啡灭字脊虎天牛幼虫10 d后,在26~28℃条件下致病力最强,相对湿度为85%~100%致病力最强,紫外光照射60 min后致病力减弱。结果表明:爪哇虫草Bd01在适宜的环境条件下对咖啡灭字脊虎天牛幼虫有较好的生防潜力,具有进一步深入研究和开发利用的前景。

In this study,an entomogenous fungus Bd01 with high pathogenicity was isolated from the larvae of Xylotrechus quadripes Chevr that died of natural diseases in the field,and the LCis 4.56×10^(5) conidia/mL of that the fungus against the larvae of X.quadripes Chevr.The method of combining morphology and ITS sequence analysis was used to identify the bacterial strain,and to test the effect of the vegetative growth and pathogenicity of the bacteria under different environmental conditions.The results showed that the bacteria is Cordyceps javanica,PPDA medium is the most suitable growth medium for the bacteria,26℃ is the most suitable for the growth of the bacteria,the relative humidity at 85%-100%,the most suitable for the growth of the bacteria,ultraviolet light irradiation 30 min is not conducive to the growth of the bacteria.After 1×10^(8) spores/mL spore suspension was inoculated with the larvae of X.quadripes Chevr for 10 days,The virulence is strongest at 26-28℃,and the virulence is strongest at a relative humidity of 85%-100%,and the virulence is weakened after 60 min of ultraviolet light irradiation.The research results indicates that C.javanica Bd01 has a good potential for biocontrol against the larvae of X.quadripes Chevr under suitable environmental conditions,and has further development and utilization prospects.