苏云金杆菌对抗性及敏感小菜蛾的拒食活性

调查了苏云金杆菌对抗性和敏感小菜蛾的拒食活性。选择性和完全拒食试验表明,Bt对抗性和敏感小菜蛾种群都有一定的拒食作用,且拒食活性随Bt浓度的增加而显著增强。相对于抗性种群,小菜蛾敏感种群对Bt杀虫剂表现了更强的拒食趋势,其拒食中浓度AFC50(0.089 3 μg/mL)显著低于抗性种群(0.148 1 μg/mL)。试验结果表明,抗性种群对有毒叶片的行为避害能力弱于敏感种群,小菜蛾对Bt杀虫剂的抗性产生应与其行为机制无关。

Anti-feeding Activity of Bacillus thuringiensis Resistant and Susceptible Population of Plutella xylostella (L.)

Selective and complete anti-feeding bioassays were used to determine the anti-feeding activity of Bacillus thuringiensis(Bt) to resistant and susceptible population of diamondback moth, Plutella xylostella (L.). Bt showed some anti-feeding activity to the third instars larvae of both populations and its activity increased significantly with the increase of its concentration. The susceptible population was more susceptible to the effect of Bt than the resistant population. Its AFC₅₀ is significant lower than that of resistant population. The resistant population had lower instinct to avoiding damage than susceptible population on treated leaves. The result implied that the resistance of diamondback moth to Bt did not relate with behavior resistance mechanism.