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多位点生物杀虫毒素BtA是通过氨基-羧基偶联剂EDC将两种生物毒素[Bacillus thuringiensis (Bt)晶体原毒素和阿维菌素]进行键合反应,形成的具有多个作用位点的生物藕合产物。通过研究小菜 蛾(Plutella xylostella L.)对BtA敏感性的消减和恢复,以及不同地域小菜蛾对其敏感性的差异,来初步 评估多位点生物杀虫毒素BtA害虫敏感性变化的规律。试验结果表明:小菜蛾室内相对敏感种群对BtA 以及它的反应底物Bt伴胞晶体和阿维菌素的敏感性稳定(LC50为0．0004-0．0020mg/ml)。在三种生物杀 虫剂的选择压力之下小菜蛾敏感性下降,2代后对BtA抗性比的增长(2．29)显著地低于Bt伴胞晶体 (8．351和阿维菌素(22．5)。小菜蛾田间种群在脱离杀虫剂的选择压力后敏感性会增加,2代后对BtA的 敏感性显著地增加了4．7倍．高于对Bt伴胞晶体的1．28倍和对阿维菌素的2．00倍。福建省七个地市 小菜蛾表现出敏感性的多态性,对BtA、Bt伴胞晶体和阿维菌素的抗性比分别为1．18-6．85、1．22- 23．93和1．58-4．77。聚类分析结果在福建省以中部地区的小菜蛾具有相对较低水平的敏感性。说明多 位点生物杀虫毒素BtA有助于延缓抗性的产生、降低抗性和迅速恢复害虫敏感性的作用。
Multi-site biocidal toxin BtA is a biocidoxin [Bacillus thuringiensis (Bt) crystal protoxin and abamectin] through the amino-carboxyl coupling agent EDC for the bonding reaction, the formation of multiple sites of action Biological coupling products. By studying the reduction and recovery of BtA sensitivity in Plutella xylostella L.and the difference in susceptibility to Plutella xylostella L.from different regions, this study preliminarily evaluated the changes of BtA susceptibility to multi-site insecticidal toxin BtA. The results showed that the susceptible population of P. xylostella was relatively stable to BtA and its substrate of Bt with crystal and abamectin (LC50: 0.0004-0.0020 mg / ml). The susceptibility of diamondback moth to Plutella xylostella was lower under the selection pressure of the three biocides, and the ratio of BtA resistance after 2 generations (2.29) was significantly lower than that of Bt companion crystals (8.351 and abamectin (22.5) .The susceptibility of the diamondback moth population to selective insecticides increased after 2 generations, and the sensitivity to BtA increased 4.7 times after 2 generations, which was significantly higher than that of Bt crystals .28 times and avermectin 2.00 times.Seven cities in Fujian Province diamondback moth showed sensitive polymorphism, resistance to BtA, Bt crystals and abamectin were 1.18-6.85, 1.22- 23.93 and 1.58-4.77 respectively.The clustering results showed that the susceptibility of Plutella xylostella to the diamondback moth in central China was relatively low, indicating that the multi-locus BtA, a biological insecticidal toxin, helps to delay the development of resistance, reduce resistance and promptly restore pest sensitivity.