一株球孢白僵菌的分离鉴定及其对茶丽纹象甲幼虫的室内致病力测定

Isolation,Identification,and Pathogenicity of a Beauveria bassiana Strain Isolated from Tea Weevils Myllocerinus aurolineatus Larvae

茶丽纹象甲是我国茶园重要的食叶害虫之一,目前以化学农药防治为主,亟需开发绿色生态环保的防控技术。为筛选出可防治茶丽纹象甲的生防菌株,本研究从田间采集了自然感病致死的茶丽纹象甲幼虫僵虫并分离出一株虫生真菌菌株。形态学特征和分子系统进化关系分析显示该菌株为球孢白僵菌Beauveria bassiana,命名为Maure 1.1。在自然化蛹和羽化温度(22℃)条件下,茶丽纹象甲幼虫在接种1×10^(5)~1×10^(8)个孢子/m L的球孢白僵菌菌株Maure 1.1孢子液后,其感病死亡率随接种后观察时间的延长而增加。其中,用最大浓度孢子通过浸虫和拌土法处理11 d时,茶丽纹象甲幼虫的累计校正死亡率分别为76.67%和73.33%,LC_(50)分别为2.00×10^(3)和1.11×10^(3)个孢子/mL,LT_(50)分别为7.87和7.84 d。上述结果表明,球孢白僵菌Maure 1.1对茶丽纹象甲幼虫具有致病活力,可作为茶丽纹象甲生物防治的候选菌株。

Tea weevil is an important tea insect pest in Chinese tea plantations,currently chemical pesticides are the main control method and environmentally friendly control strategies are needed urgently.To screen potential pathogenic strains for biological control of tea weevils,an entomopathogenic fungi strain isolated from field-collected infected dead Myllocerinus aurolineatus larvae was studied.Morphological characteristics and phylogenetic tree analysis revealed that the isolated strain was Beauveria bassiana(Bals.)Vuill,herein named as Maure 1.1.Under the natural pupating and hatching temperature(22℃),the laboratory pathogenicity increased with the prolonged post-inoculation observation period when M.aurolineatus larvae were exposed to B.bassiana Maure 1.1 at a concentration of 1×10^(5)-1×10^(8) conidia/mL.When applied at the highest concentration,the Maure 1.1 strain led to 76.67% and 73.33% of cumulative corrected mortalities with immersion and soil mixing methods,respectively,at 11 days post-treatment.The LC_(50) were 2.00×10^(3) and 1.11×10^(3) conidia/mL,and the LT_(50) were 7.87 and 7.84 days for the two methods,respectively.These results indicate that the isolated B.bassiana Maure 1.1 strain is biologically pathogenic to tea weevils’larvae and a potential candidate strain for M.aurolineatus biocontrol.