Infection Effect of Nomuraea riley MZ060806-XW against Helicoverpa armigera Larvae

[Objective] The propose was to use the Nomuraea rileyi to make the biological control of Helicoverpa armigera.[Method] The pathogenicity research was conducted on the 2nd and 3nd instar larvae of H.armigera with conidia of N.rileyi MZ060806-XW under 5 different concn.of 3.5×104-3.5×108 spores/m inoculated by dipping method.[Result] The pathogenicity of conidia of N.rileyi MZ060806-XW to the mortality rate of the 2nd and the 3nd instar larvae was 84.68% and 82.23% resp.under concn.of 3.5×108 spores/ml on 8th day.LC50 of the 2nd and 3nd instar larvae were 3.975×104 and 7.794×104 spores/ml on 8th day.Under 5 concn.of 3.5×104-3.5×108 spores/ml,the LT50 of the 2nd instar larvae were 9.774,6.322,5.415,4.559 and 4.051 d resp.and that of the 3nd instar larvae was respectively 9.462,6.842,5.365,4.636 and 4.177 d.With the increase of spore concn.,the LC50 time was gradually shortened and the insect mortality was gradually increased;with the process of the drug application time,the LC50 concn.was gradually decreased.[Conclusion] The control effect of N.rileyi MZ060806-XW on the 2nd instar larvae of H.armigera was higher than that on 3nd instar larvae.N.rileyi used in the biological control of the pests had the value of development and utilization.