棉铃虫对氰戊菊酯和顺式氰戊菊酯抗性水平的比较

COMPARISON OF RESISTANCE LEVEL BETWEEN FENVALERATE AND ESFENVALERATE IN HELICOVERPA ARMIGERA HUBNER

测定了氰戊菊酯和顺式氰戊菊酯对不同棉铃虫品系３龄幼虫的毒力。结果表明，两者对敏感品系的ＬＤ５０值相差８．７倍，而对一系列抗性品系两者ＬＤ５０值相差２４．３～１７２．１倍；不同棉铃虫品系对氰戊菊酯和顺式氰戊菊酯的抗性水平也存在显著差异，对氰戊菊酯的抗性为８１．８～２１４２．８倍，对顺式氰戊菊酯的抗性为２３．８～１６４．６倍。用室内选育的山东阳谷Ｓ６抗性品系进行测定，结果显示，增效醚对氰戊菊酯和顺式氰戊菊酯的增效比分别为１１９．３和４．３，说明棉铃虫对两者的氧化代谢抗性机制差异很大。氰戊菊酯和顺式氰戊菊酯对棉铃虫的毒力以及棉铃虫对两种药剂的抗性水平并不是简单的４倍关系，氰戊菊酯中大量无效异构体的存在可能有利于氧化代谢抗性机制的演化。

Resistance levels between fenvalerate and esfenvalerate in nine strains of Helicoverpa armigera Hübner were compared. There was only 8.7fold difference between the toxicity of these two insecticides in the susceptible strain, but 24.3 to 172.1fold difference in resistant strains. The resistance level to these two insecticides also differed significantly, with 81.8fold to 2 142.8fold resistance to fenvalerate and 23.8fold to 164.6fold resistance to esfenvalerate. The synergism ratios of PBO to fenvalerate and esfenvalerate in resistant YGS6 strain were 119.3 and 4.3 respectively. It is suggested that the relationship of toxicity between fenvalerate and esfenvalerate is not simply fourfold, and inefficient isomers of fenvalerate may favor the evolution of oxidative resistance mechanism to fenvalerate.