Department of Entomology, Purdue University, West Lafayette, IN 47907, USA.
J Econ Entomol. 2009 Dec;102(6):2289-95. doi: 10.1603/029.102.0634.
The corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), can cause serious losses in many field and vegetable crops throughout the United States. Since their introduction, pyrethroid insecticides have become the primary insecticide class for managing H. zea. However, resistance has been reported in the southern United States and has recently became a concern in the Midwest after the observation of sporadic control failures and a decreased efficacy of pyrethroids in small-plot field trials. Larvae collected from Lafayette, IN, Vincennes, IN, and Collinsville, IL, were used to establish laboratory colonies in 2006 and 2007. Larvae from these colonies were tested for resistance to the pyrethroid insecticide bifenthrin by using topical assays. Adult males collected from pheromone traps in Lafayette were tested for resistance to cypermethrin by using the adult vial test (AVT) method. Resistance ratios of > or =8 were observed for the larvalbifenthrin assays in 2006 and 2007 in all colonies except for the 2007 Illinois colony. AVT assays conducted with cypermethrin showed approximately 15% survival in both 2006 and 2007 at the 5 microg per vial discriminating dose. These results suggest that low to moderate levels of pyrethroid resistance are present in these populations.
玉米穗虫，Helicoverpa zea（Boddie）（鳞翅目：夜蛾科），可对美国许多田间和蔬菜作物造成严重损失。自从引入以来，拟除虫菊酯杀虫剂已成为防治 H. zea 的主要杀虫剂类别。然而，在美国南部已经报道了抗药性，并且在观察到零星的控制失败和田间小区试验中拟除虫菊酯的效果降低后，最近在中西部地区引起了关注。2006 年和 2007 年，从印第安纳州拉斐特、印第安纳州文森斯和伊利诺伊州柯林斯维尔采集幼虫，用于建立实验室群体。用触杀试验测定来自这些群体的幼虫对拟除虫菊酯杀虫剂联苯菊酯的抗药性。从拉斐特性诱捕器收集的成年雄性用成虫管测试（AVT）方法测定对氯氰菊酯的抗药性。除了 2007 年的伊利诺伊州群体外，2006 年和 2007 年所有群体的幼虫联苯菊酯测定的抗药性比值均大于或等于 8。在 5 微克/管的鉴别剂量下，2006 年和 2007 年进行的氯氰菊酯 AVT 测定显示约有 15%的成虫存活。这些结果表明，这些种群存在低至中度的拟除虫菊酯抗性。
