莱氏野村菌MZ060806-XW菌株对棉铃虫幼虫的感染效应

[目的]研究利用莱氏野村菌对棉铃虫进行生物防治的效果。[方法]采用浸渍接种法,用莱氏野村菌MZ060806-XW分生孢子的5个浓度（3.5×104～3.5×108个/ml）对棉铃虫2龄和3龄幼虫进行致病性研究。[结果]在莱氏野村菌MZ060806-XW分生孢子3.5×108个/ml浓度下;第8天2龄和3龄的幼虫死亡率最高分别达84.68%和82.23%;第8天,2龄和3龄幼虫的致死中浓度（LC50）分别为3.975×104和7.794×104个/ml。在3.5×104～3.5×108个/ml的5个浓度处理下,2龄幼虫的致死中时间（LT50）依次为9.774、6.322、5.415、4.559和4.051d,3龄幼虫的LT50分别为9.462、6.842、5.365、4.636和4.177d。随着孢子浓度的增加,LT50逐渐缩短,虫口的死亡率逐步增加;随着施药时间的推移,LC50逐渐减小。[结论]利用莱氏野村菌MZ060806-XW菌株对棉龄虫2龄幼虫的防治效果高于3龄幼虫。莱氏野村菌用于害虫的生物防治具有开发利用价值。

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.