害虫抗药性治理策略-多位点杀虫毒素的研究

Control Strategy of Insect Pest Resistance to Insecticides by Using Multiple Toxins Insecticide

害虫对杀虫剂产生抗药性,降低了农药使用效率,增大了农药用量,污染了环境。害虫抗药性可分为单一抗性、多重抗性、交互抗性。害虫抗药性由遗传因素、生态因素和操作因素决定,3种因素作用不当都能引起害虫抗性的发生。农药有效成分作用于害虫的特定位点,害虫对农药抗药性就是克服农药位点作用,使之失效、钝化,保持农药作用位点敏感性是减缓害虫抗药性的有效方法。每一种农药对害虫都有一个主要作用位点,每一种害虫都存在多个农药作用位点。多位点杀虫毒素的研究是克服害虫抗药性的有效途径。将B.t.的杀虫毒素进行酶切改造,形成带末端氨基的原毒素,将阿维菌素的羟基进行激活、衍生化,形成带羧基的杀虫毒素衍生物,最后利用氨基-羧基偶联剂(EDC)进行藕合,实现两种生物毒素的结构改造和生化结合。BtA解决了生物农药杀虫谱窄和杀虫速率慢的弱点。

The present paper dealt with control strategy of in-sect pest resistance to insecticides by using multipletoxins insecticide. The development and mechanism of pest resistance to insecticides were discussed. The multipletoxins insecticide was introduced to overcome pest resistances to insecticides. Conjugation ofδ-endotoxin fromBacillus thuringiensis with abamectin produced by Streptomyces avermitilis was carried out to form a new type ofbiocide BtA based on 揋ermany-China Scientific Cooperation?research project for control of agricultural insect pest.The successful biochemical linkage was designed to conjugate an amino group in B.t. protoxin with a carboxyl group incarboxylated abamectin under the treatment of conjugator EDC [1-Ethyl-3-(3-dimethylaminopropyl carbodiimidehydrochlo-ride)]. The conjugated BtA caused 87.14% mortalities in larva P. xylostella, 93.75% in adult Myzus persicae(Sulzer) (Hom., Aphididae) and 89.33% in adult Phyllotreta vittata Fabricius (Col., Chrysomelidae) as compared to 48.33% by theB.t. crystal only in P. xylostella. The symptoms caused by conjugated BtA in the 3rd instar P. xylostella were black colorin the head part and white-yellow in the abdomen of dead larvae, which differed from the black color or the white-yellow all along the body caused by either the B.t. crystal or the abamectin, respectively. It was concluded that theconjugated BtA biocide had broader host spectrum and faster killing speed than B.t. crystal or abamectin functionedalone in control of the agricultural pests with less pest resistance.