对韭菜迟眼蕈蚊幼虫高毒力Bt资源筛选及效果评价

【目的】为开发防治韭菜迟眼蕈蚊Bradysia odoriphaga的生物杀虫剂,本研究评价了185株苏云金芽胞杆菌Bacillus thuringiensis对韭菜迟眼蕈蚊幼虫的杀虫活性。【方法】采用浸叶饲喂法对供试菌株进行室内生物学测定,用盆栽试验对筛选到的对韭菜迟眼蕈蚊高毒力的FPT3菌株进行防效验证,通过SDS-PAGE电泳技术对FPT3菌株的杀虫晶体蛋白进行分析,并采用Biolog微生物自动分析系统对FPT3菌株进行了生理生化测定。【结果】在1×10~8 cfu/m L浓度下,对韭菜迟眼蕈蚊2龄幼虫3 d的校正死亡率在80%以上的菌株有12株,其中FPT3菌株对韭菜迟眼蕈蚊2龄幼虫的杀虫活性最高;FPT3菌株表达70 ku左右蛋白,具有典型的苏云金芽胞杆菌的生理生化特征;FPT3菌株对韭菜迟眼蕈蚊1龄和2龄幼虫具有较高的杀虫活性,LC_(50)分别为1.206×10~6 cfu/m L和2.577×10~6 cfu/mL,室内盆栽试验明确了FPT3菌株对韭菜迟眼蕈蚊的防治效果达77.76%。【结论】FPT3菌株能有效地控制韭菜迟眼蕈蚊的发生,具有良好的应用前景。

Effectiveness of high virulence Bt resources as a means of controlling Bradysia odoriphaga larvae

Objectives] To develop biological insecticides against Bradysia odoriphaga. Methods] The toxicity of one hundred and eighty five Bacillus thuringiensis strains to B. odoriphaga larvae was evaluated using the leaf immersion feeding method and pot trials. Insecticidal crystal protein of FPT3 was analyzed by SDS-PAGE. Physiological and biochemical characters of FPT3 were determined using the Biolog system. Results] All 12 Bt strains caused > 80% mortality to B. odoriphaga larvae but FPT3 was the most toxic. The FPT3 strain had typical physiological and biochemical characteristics of Bt and expressed protein of 70 ku. The LC50 of the FPT3 strain against 1st and 2nd instar larvae was 1.206×106 cfu/mL and 2.577×106 cfu/mL, respectively. Pot trials demonstrated that the control effect of FPT3 on B. odoriphaga larvae was 77.76%. Conclusion] FPT3 can effectively control B. odoriphaga, and has potential for application in the field.