棉铃虫对氰戊菊酯抗性机理研究

MECHANISM OF FENVALERATE RESISTANCE IN HELICOVERPA ARMIGERA HUBNER

对于室内选育的棉铃虫抗性品系（ＹＧ－Ｒ，Ｒｄ）和采自田间的抗性种群（ＹＧ９２２１，ＹＧ９２４１，ＹＧ９３２１），ＰＢＯ对氰戊菊酯都具有明显的增效作用，增效比为１９．５～１６９．５倍，而ＤＥＦ和ＴＰＰ对氰戊菊酯几乎没有增效作用。Ｒｄ抗性品系三龄幼虫多功能氧化酶艾氏剂环氧化活力是ＹＳ－Ｓ敏感品系的１．３６倍，而ＹＧ－Ｒ和Ｒｄ两个抗性品系分别与ＹＳ－Ｓ敏感品系相比，三龄幼虫酯酶活力没有差异。因此，多功能氧化酶解毒作用增强是棉铃虫对氰戊菊酯产生抗药性的主要因子，而酯酶与抗性无关。用１４Ｃ－氰戊菊酯进行的表皮穿透研究表明，氰戊菊脂在抗性品系和敏感品系的表皮穿透速率上存在差异，表皮穿透速率降低是棉铃虫对氰戊菊酯产生抗性的一个因子。棉铃虫对氰戊菊酯抗性品系与ＤＤＴ具有交互抗性，间接表明了神经敏感性下降也可能是棉铃虫对氰戊菊酯产生抗性的一个因子。

PBO significantly synergised fenvalerate in the third luster larvae of both laboratory selected resistantstrains (YG-R, Rd) and field-collected resistant strains (YG9221, YG9241, YG9321 ) of Helicoverpa armigera, withthe synergism ratios ranging from 19. 5 to 169. 5 fold at the LD50 level, but fenvalerate were hardly synergised byTPP and DEF. The aldrin epoxidase activities of mixed function oxidase (MFO) in the third instar larvae of Rd resistant strain were 1. 36 times as high as those of the YS-S susceptible strain and there was no difference in the esteraseactivities to α-naphthylacetate among the resistant strains (YG-R, Rd) and the susceptible strain (YS-S). This indicated that fenvalerate resistance was principally due to the metabolic mechanism of MFO, the esterase was not imPOrtant in fenvalerate resistance in H. armigera. The rate of cuticular Penetration of 14C-fenvalerate in the 3rd instar larvae was higher in the susceptible strain than in the resistant strain (Rd). YG-R strain posscessing cross resistance toDDT suggdsted that nerve insensitivity might be another mechanism. of fenvalerate resistance in Helicoverpa armigera.