Biological Characteristics and Insecticidal Activities of Different Beauveria bassiana Isolates Against Myllocerinus aurolineatus

In order to rescreen high virulence strains against Myllocerinus aurolineatus, the growth rate, sporulation, germination rate and insecticidal activity of eight Beauveria bassiana isolates, which were isloated from dead body of M. aurolineatus, were investigated. The results showed that the eight isolates could be seperated into two groups: hyphae type and spore type on the SDAY medium. The hyphae type strains of XJBb3001 and XJBb3007 grew faster than the others, but they are useless hyphae and no producing spores. The strain XJBb3005 had the largest number of sporulation, and there were very significant differences in sporulation number between strain XJBb3005 and other isolates. There is no difference among the spore germination rate of the strain XJBb3002, XJBb3003, XJBb3004, XJBb3005, XJBb3006, XJBb3008. Bioassay evaluation were carried out by dipping in spore suspension (1.0?107spores穖L-1), and the results showed that the isolate XJBb3005 had highest virulent, and corrected mortality of M. aurolineatus reached 100% at 7 d after treatment. The LT50 value was 3.46 d,LT90 value was 5.45 d, and infected rate was 93.75%, respectively.