Screening of a Highly Virulent Strain for Diamondback Moth Control and Its Field Efficacy

By comparison of sporulation and virulence,29 strains of Beauveria bassiana isolated from Lepidopteran insects were screened for their pathogenicity to diamond moth,Plutella xylostella.Bb2390,a highly virulent strain was chosen,with LC50 on the 2nd instar larvae at 1.56×105 conidia mL 1,and LT50 at 4.61 d under the concentration of 1.0×107conidia mL 1.The strain was pathogenic to all the stages of diamond moth,with mortality to eggs,2nd instar larvae,pupae and adults were 37.2%,90.3%,58.8% and 24.5% respectively.The wettable powder of B.bassiana was used for field efficacy test against the larvae of P.xylostella,the control efficacy was 65.85%,significantly higher than aqueous conidial suspension with control efficacy 51.66%.