莱氏野村菌Nr05菌株的培养性状及其对斜纹夜蛾的毒力

Cultural Characteristics of Nomuraea rileyi Nr05 and Its Virulence to Spodoptera litura

以斜纹夜蛾罹病虫体上新分离出的一种莱氏野村菌Nr05菌株为对象,比较了其与实验室保存的菌株对斜纹夜蛾幼虫的毒力,与银纹夜蛾核多角体病毒、苦参碱和苏云金杆菌混用对斜纹夜蛾幼虫的控制效果,及其在不同培养基上的培养性状。结果表明:Nr05菌株对斜纹夜蛾具有很强的毒力,以1.0×108孢子/ml的孢子液接种到斜纹夜蛾4龄幼虫上,累积校正死亡率达62.1%,LT50为8.99d,致死率和致死速度明显高于其他真菌菌株。莱氏野村菌Nr05菌株与攻蛾混用防治斜纹夜蛾具有明显增效作用,平均累计校正死亡率达79.3%,比相同浓度的单剂增加13.7个百分点;LT50为5.2d,比相同浓度的攻蛾和真菌单剂分别减少1.1d和4.7d。Nr05菌株在PPDA培养基上生长优于SDAY。

The new strain of Nomuraea rileyi Nr05, isolated from Spodoptera litura, was tested for its cultural characteristics, virulence to S. litura and the synergism with Autographa californica NPV, E- ploxugar , Bacillus thuringiensis. Results showed that N. rileyi Nr05 obviously controlled S. litura. Its LT50 value to the 4th instar larvae of S. litura was 8.99 d and adjusted accumulative mortality was 62.1% when concentration was 1 ×10^8 conidia/ml. Combinative application of A. californica NPV and the strain resulted in a higher controlling efficacy to the 4th instar larvae of S. litura, indicating the synergism of the agents. The adjusted accumulative mortality reached 73.9%, 13.7% higher than using N. rileyi Nr05 alone. Its LT50 value decreased 1.1 d and 4.7 d compared with using A. californica NPV and N. rileyi Nr05 alone, respectively. The cultural characteristics of N. rileyi Nr05 was investigated.Results indicated that PPDA was more suitable for N. rileyi to grow than SDAY.