东南沿海地区小菜蛾对Bt δ-内毒素和Bt制剂的抗性检测

Field-evolved resistance to Bt δ-endotoxins and Bt formulation in Plutella xylostella from the southeastern coast region of China

采用浸叶法测定了2003年秋季、2004年春季采自广东惠州、福建福州、浙江杭州和江苏南京的小菜蛾Plutellaxylostella田间种群对Cry1Aa、Cry1Ab、Cry1Ac和Cry2Aa以及Bt制剂kurstaki亚种(Bacillusthuringiensissubsp.kurstaki,Btk)的抗性水平。与敏感品系PHI_S相比,广东惠州田间小菜蛾种群的抗性水平最高,其对Cry1Ab和Cry1Ac的抗性分别达到了168和120倍,均为高抗水平;对Btk制剂的抗性有47倍,达到了中抗水平;对Cry1Aa和Cry2Aa具有低水平抗性(分别为5.8和5.6倍)。福建福州、浙江杭州和江苏南京田间小菜蛾种群抗性水平相近,对Cry1Ab和Cry1Ac具有低至中等水平抗性(8～28倍),对Btk制剂具有低水平抗性(3.5～7倍),对Cry1Aa和Cry2Aa还没有产生明显抗性。因此,在我国东南沿海地区要注意Btk制剂与Bt其他亚种制剂或其他生物杀虫剂轮换使用,以减小Bt制剂对小菜蛾的选择压力,延缓小菜蛾对Bt抗性的发展。

Levels of resistance to Cry1Aa, Cry1Ab, Cry1Ac, Cry2Aa and Bt formulation （Bacillus thuringiensis subsp, kurstaki, Btk） in four field populations of PluteUa xylostella collected respectively from Huizhou of Guangdong Province （GD-HZ）, Fuzhou of Fujian Province （FJ-FZ）, Hangzhou of Zhejiang Province （ZJ-HZ） and Nanjing of Jiangsu Province （JS-NJ） during the autumn of 2003 and the spring of 2004 were investigated. Compared with the susceptible PHI-S strain, the GD-HZ population exhibited high level resistance to CrylAb and CrylAc （168 and 120-fold respectively）, middle level resistance to Btk （47-fold） and low level resistance to Cry1Aa and Cry2Aa （5.8 and 5.6-fold, respectively）. The FJ-FZ, ZJ-HZ and JS- NJ populations showed similar resistance levels, with middle level resistance to CrylAb and CrylAc （8 to 28- fold）, low level resistance to Btk （3.5 to 7-fold） and no resistance to Cry1Aa and Cry2Aa. So, it was proposed that the rotations of Btk with other Bt subspecies or other kinds of bioinsecticides should be encouraged in order to delay resistance development of P. xylosteUa in southeastern China.