Irrigated Agriculture Research and Extension Center, Washington State University, Prosser, WA 99350, USA; Department of Entomology, Washington State University, Pullman, WA 99164, USA.
Washington State University Area Extension, Pasco, WA 99301, USA.
Pestic Biochem Physiol. 2020 May;165:104553. doi: 10.1016/j.pestbp.2020.104553. Epub 2020 Mar 4.
Thrips tabaci is a key pest of onions, especially in the Pacific Northwestern USA. Management of T. tabaci is dominated by the application of various insecticides. However, T. tabaci is known to develop insecticide resistance which possibly leads to control failures, crop loss, and environmental concern. Here, we evaluated resistance status of T. tabaci populations from conventional and organic commercial onion fields to three widely used insecticides: oxamyl, methomyl, and abamectin with on-field concentration-mortality bioassays. The biochemistry and molecular mechanisms underlying resistance to these insecticides were also investigated by using enzymatic assays and detecting resistance-associated mutations. Field-evolved resistance to oxamyl, methomyl and abamectin were detected in most of the T. tabaci populations collected from conventional onion farms. At the labeled field rate, all the tested insecticides, particularly methomyl and oxamyl, had significantly reduced efficacy. Enzymatic assays of insecticide target and detoxification enzymes indicated that T. tabaci populations in Western USA onions harbor multiple mechanisms of resistance including enhanced activities of detoxification enzymes and target site insensitivity. Our results provide new information in understanding the dynamics of T. tabaci adaptation to multiple insecticides, which will help to design sustainable insecticide resistance management strategies for T. tabaci. Furthermore, this study provides the foundation for future research in identifying the biochemical and molecular markers associated with insecticide resistance in T. tabaci.
烟粉虱是洋葱的主要害虫，尤其是在美国太平洋西北地区。对烟粉虱的管理主要依赖于各种杀虫剂的应用。然而，烟粉虱已知会产生抗药性，这可能导致防治失败、作物损失和环境问题。在这里，我们使用田间浓度-死亡率生物测定法，评估了来自传统和有机商业洋葱田的烟粉虱种群对三种广泛使用的杀虫剂：氧乐果、灭多威和阿维菌素的抗药性状况。还通过酶活性测定和检测抗性相关突变，研究了这些杀虫剂的抗性的生化和分子机制。在从传统洋葱农场收集的大多数烟粉虱种群中，都检测到了对氧乐果、灭多威和阿维菌素的田间进化抗性。在标签推荐剂量下，所有测试的杀虫剂，特别是灭多威和氧乐果，效果显著降低。对杀虫剂靶标和解毒酶的酶活性测定表明，美国西部洋葱中的烟粉虱种群具有多种抗性机制，包括解毒酶活性增强和靶标部位不敏感。我们的研究结果为了解烟粉虱对多种杀虫剂的适应动态提供了新的信息，这将有助于设计烟粉虱抗药性的可持续管理策略。此外，本研究为未来研究确定与烟粉虱抗药性相关的生化和分子标记奠定了基础。
