几种杀虫真菌对二化螟幼虫的毒力测定与高毒力菌株的分子鉴定
Virulence of several insecticidal fungi against Chilo suppressalis larvae and molecular identification of highly virulent strains
洪 勇1** 林华峰1*** 岳霄霄1 刘 苏1 叶恭银2
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DOI：10.7679/j.issn.2095-1353.2015.082
作者单位：1. 安徽农业大学植物保护学院，合肥 230036; 2. 浙江大学昆虫科学研究所，杭州 310058
中文关键词：白僵菌，二化螟，分子序列，电镜，系统树
英文关键词：Beauveria bassiana, Chilo suppressalis, molecular identification, electron microscope, phylogenetic tree
中文摘要： 【目的】 测定杀虫真菌对二化螟Chilo suppressalis (Walker) 幼虫的室内毒力，明确高毒力菌株的种类，为应用杀虫真菌防治二化螟提供理论基础。【方法】 采用喷雾法测定10株杀虫真菌在同种浓度、湿度和温度下对二化螟幼虫的室内毒力，选择毒力最强的菌株，利用扫描电镜观察杀虫真菌分生孢子对二化螟的侵染过程；根据该菌株的生物学特性，利用白僵菌Beauveria sp. 18S rDNA ITS 序列进行PCR 扩增、琼脂糖凝胶电泳检测和序列分析，并在核酸序列数据库中进行同源性序列对比。【结果】 真菌YQ147、QING、Bbr14、Bbr84在浓度为1.0×108孢子/mL下均对二化螟幼虫具有较强的致病力，其中真菌YQ147在处理后第10天对二化螟累计校正死亡率达到78.4%，LT50为5.8 d，分子鉴定的结果显示该菌为白僵菌属球孢白僵菌Beauveria bassiana。【结论】 明确了球孢白僵菌对二化螟的室内毒力最强，这为利用其对二化螟进行生物防治提供了基础。
英文摘要： [Objectives] To identify fungal strains with high virulence to Chilo suppressalis larvae and provide a theoretical foundation for the biological control of C. suppressalis. [Methods] The virulence of 10 insecticidal fungi to C. suppressalis larvae were measured under the same conditions (spore concentration, temperature and humidity) in a laboratory and the infestation process of insecticidal fungal spores observed. A pair of 18S rDNA universal primers of Beauveria sp. were used to identify the most virulent strains. [Result] At a concentration of 1.0×108 spores/mL, the fungal strains YQ147, QING, Bbr14, and Bbr84 displayed strong virulence against 2nd instar larvae of C. suppressalis, and the YQ147 strain achieved the highest cumulative corrected mortality of 78.4% with a LT50 of 5.8 d after 10 d. Molecular identification confirmed that this fungus was Beauveria bassiana. [Conclusion] Beauveria bassiana is highly virulent to C. suppressalis and may be an effective agent for the biological control of this pest.