对久效磷抗性棉铃虫品系的选育及其乙酰胆碱酯酶的研究

用久效磷对采集于山东聊城抗性地区的棉铃虫Helicoverpa armigera (Huebner)进行抗性品系选育，经过10代的室内选育，抗性倍数达211．88倍，为选育前的6．67倍，发现筛选后对氰戊菊酯，氯氰菊酯和灭多威的抗生分别下降了8．13，7．44和13．36倍，对甲基对硫磷和辛硫酸的抗性基本保持不变，这说明久效磷与其他5种被试药剂之间没有明显的交互抗性，还对抗，感棉铃虫体内AChE进行了研究，对久效磷抑制粗酶液的实验表明，抗性品系锦铃虫体内AChE的交互抗笥，还原抗，感棉铃虫体内AChE进行研究，对久效磷抑制粗酶液的实验表明，抗性品系棉铃虫体内AChE的I50是敏感品系的3．18倍，酶液纯化使抗，感品系AChE的I50分别下降6．69和3．49倍，说明粗提液中存在AChE保护因子，且这种保护因子在抗性品系中更有效，但纯化后，抗，感品系的AChE敏感性之间仍存在1．66倍的差异，此外，两品系AChE的动力学参数也存在显差异，由此认为AChE敏感性降低与其它因子共同组成了棉铃虫对久效磷的抗性机制。

Laboratory selection formonocrotophos resistant strain of Helicoverpa armigera(Hübner)and study on itsacetylcholinesterase

Monocrotophos resistance was selected in laboratory with the field resistant cotton bollworm,Helicoverpa armigera(Hübner)coll ected from Liaocheng County,Shandong Province.After ten selections with monocrot ophos during sixteen generations,the resistance increased 6.67-fold and was as high as 211.88-fold when compared with a susceptible strain collected from Xinjiang.But the resistance of the selected strain to fenvalerate,cyperme thrin and methomyl decreased by 8.13-，7.44-and 13.36-fold,respectively,du ring the selection.Methylparathion and phoxim resistance was basically unchanged as compared with that of F0.These indicate no significant cross-resistance between monocrotophos and the other 5 insecticides tested.Acetylcholinesterase(A ChE)in resistant and susceptible H.armigera was also studied.The results showed that AChE in resistant strain was much less sensitive to monocrotophos.The I 50 value for resistant AChE was 3.18-fold higher than that for susceptible .Partial purification of AChE to remove esterase and some other proteins increased the sensitivity dramatically.The I50 reduced by 6.69-fold and 3.49 -fold for resistant and susceptible strain,respectively.This indicated that the re might be some factors protecting AChE，and which was more powerful in resista nt strain.Even so,there was still 1.66-fold difference in the I50 value of purified AChEs from resistant and susceptible strains.Kinetic parameters of A ChE also showed significant difference between these two strains.So,it is concluded that the decreased sensitivity of AChE together with some other factors contributes to monocrotophos resistance.