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【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 r DNA 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/m L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。
【Objective】 The purpose of this study was to determine the indoor toxicity of insecticidal fungi to Chilo suppressalis (Walker) larvae and to clarify the types of high virulent strains, providing theoretical basis for the application of insecticidal fungi to prevent and control the stem borer. 【Method】 The indoor virulence of 10 insecticidal fungi against the stem borer, Chilo suppressalis (L.), in the same concentration, humidity and temperature was measured by spray method. The strains with the strongest virulence were selected. The conidial pairs According to the biological characteristics of the strain, Beauveria sp. 18S rDNA ITS sequence was used for PCR amplification, agarose gel electrophoresis detection and sequence analysis, and carried out in the nucleic acid sequence database Homology sequence comparison. 【Result】 The results showed that the fungi YQ147, QING, Bbr14 and Bbr84 all had strong virulence to the rice stem borer larvae at the concentration of 1.0 × 108 spores / m L, of which fungi YQ147 accumulated on the 10th instar The corrected mortality rate reached 78.4% and the LT50 was 5.8 days. The molecular identification showed that the strain Beauveria bassiana was Beauveria bassiana. 【Conclusion】 It is clear that Beauveria bassiana has the strongest indoor toxicity to Chilo suppressalis, which provides the basis for the biological control of Chilo suppressalis.