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[目的]分离筛选出对鳞翅目害虫高毒力的新苏云金杆菌。[方法]通过温度筛选法从长白山区土壤中分离出苏云金杆菌,再通过生物测定和毒力测定筛选出高毒力苏云金杆菌。[结果 ]从150份土壤样品中分离出18株苏云金杆菌,其分离率为12.0%,其中山地分离率为8.5%,农田分离率为16.2%。活性测定结果 ,18株菌株中对小菜蛾、斜纹夜蛾及甜菜夜蛾致死率超过90%的菌株分别有17株、5株和4株,其中YN1-1菌株对3种害虫都表现出高活性。毒力测定结果,YN1-1菌株对甜菜夜蛾和斜纹夜蛾的速效性最好;对甜菜夜蛾高毒力菌株依次为YN6-2>YN1-1>YN4-2>YN2-6;对斜纹夜蛾高毒力菌株依次为YN4-4>YN1-1>YN6-1>YN4-1>YN2-1。[结论]经活性测定和毒力测定,最终筛选出广谱性、速效性及高毒力的YN1-1为目标菌株。
[Objective] The research aimed to isolate and isolate new strains of Bacillus thuringiensis which are highly virulent to lepidopteran pests. [Method] Bacillus thuringiensis was isolated from the soil of Changbai Mountain by temperature screening method, and then the highly virulent Bacillus thuringiensis was screened out through bioassay and virulence determination. [Result] Eighteen strains of Bacillus thuringiensis were isolated from 150 soil samples. The isolation rate was 12.0%. The isolation rate in mountain area was 8.5% and that in farmland was 16.2%. Among the 18 strains, 17 strains, 5 strains and 4 strains were found to have lethal lethal to Plutella xylostella, Spodoptera litura and Spodoptera exigua. The YN1-1 strains showed high active. The result of virulence showed that YN1-1 had the best effect on beet armyworm and Spodoptera litura. The high virulent strains of Beet armyworm were YN6-2> YN1-1> YN4-2> YN2-6, High virulent strains of Spodoptera litura were YN4-4> YN1-1> YN6-1> YN4-1> YN2-1. [Conclusion] The YN1-1 with broad spectrum, quick effect and high virulence was selected as the target strain by activity assay and virulence determination.