桔小实蝇高致病性球孢白僵菌菌株的筛选

Filter of Beauveria bassiana Strains with High Virulence to Bactrocera dorsalis

为筛选对桔小实蝇Bactrocera dorsalis(Hendal)有高毒力的球孢白僵菌Beauveria bassiana菌株,本文选取了对双翅目蝇类有致病性的球孢白僵菌菌株12株(Bb1824、Bb1840、Bb1853、Bb1981、Bb1995、Bb2003、Bb268、Bb853、Bb886、Bb1035、Bb1205、Bb2264),通过菌落生长形状观察、产孢量测定、孢子萌发率的测定的方法筛选出菌株营养生长速度快、产孢量大、孢子萌发率高的优势菌株6株(Bb886、Bb1035、Bb1824、Bb1981、Bb2003、Bb1840);再通过生物测定的方法,在6株优势菌株中筛选出了对桔小实蝇幼虫感染率最高、死亡率最高、LT50最小的Bb886菌株,该菌株对桔小实蝇幼虫的感染率为86.7%,校正死亡率达89.2%,在孢子浓度为2×107个/mL时的LT50仅为5.18天。

Twelve strains of Beauveria bassiana（Bb1824,Bb1840,Bb1853,Bb1981,Bb1995,Bb2003,Bb268,Bb853,Bb886,Bb1035,Bb1205 and Bb2264） were seleted,which had virulence to dipterous insect.Through observed colony morphological characteristics,mensurate the sporulation and conidia germination ratio,six strains of Beauveria bassiana（Bb886,Bb1035,Bb1824,Bb1981,Bb2003 and Bb1840） were dominant than others,which have the characteristics of fast growth of mycelium,higher sporogenous ability and higher conidia germination ratio.By the method of bioassay,the strain of Bb886 was filtered from 6 strains that has highest infection ratio,mortality and lowest LT50 to Bactrocera dorsalis larvae,the infection ratio was 86.7%,corrected mortality was 89.2%,and LT50 was 5.18 days under the 2 ×107/mL conidia condition.