小菜蛾对溴氰菊酯的抗性消退与抗性恢复动态

Trends of resistance decline and resistance recovery to deltamethrin in diamondback moth, Plutella xylostella L.

利用选育的抗溴氰菊酯小菜蛾用Plutella xylostella L.品系第100代为虫源,在不接触任何杀虫剂条件下继代繁殖50代,观察了小菜蛾对溴氰菊酯的抗性消退动态;同时对消退过程中的小菜蛾施加溴氰菊酯选择压力和利用消退过程中的小菜蛾与抗性品系、非抗性品系杂交,观察了小菜蛾对溴氰菊酯的抗性恢复动态。结果表明:①小菜蛾对溴氰菊酯的抗性消退表现为1～15代较慢,15～25代较快,25代后又缓慢的趋势,抗性消退也使氯菊酯、氯氰菊酯交互抗性水平下降;②溴氰菊酯抗性消退过程中,当连续受到一定程度的溴氰菊酯选择压力时,抗性会在几代之内很快恢复;③与其它品系杂交的后代受到一定剂量溴氰菊酯连续处理后,3～4代就能达到或接近抗溴氰菊酯品系第100代的抗性水平,对氯菊酯、氯氰菊酯的交互抗性水平也随之迅速上升。

The resistance decline and recovery of deltamethrin in diamondback moth,Plutella xylostella L.,were studied using the F100 of resistance strain to deltamethrin.The results indicated that;(1) the resistance decline is slower from F1 to F15,faster from F15to F25,and slower a-gain after F25,while the sensibility to permethrin and cypermethrin in the diamondback moth of the decline populations increased;(2)continuous treatment with deltamethrin to the diamond-back moth of resistance decline population,the resistance recovered rapidly within several generations;(3) after treatment with deltamethrin(2.5μg/larva),the descendants from the decline population x resistance strain to deltamethrin,resistance strain to dimehypo and susceptible strain to deltamethrin,their resistance to deltametrin recovered within 3-4 generations,and their cross resistance to permethrin and cypermethrin also increased rapidly.