Gassmann Aaron J, Shrestha Ram B, Jakka Siva R K, Dunbar Mike W, Clifton Eric H, Paolino Aubrey R, Ingber David A, French B Wade, Masloski Kenneth E, Dounda John W, St Clair Coy R
Department of Entomology, Iowa State University, Ames, IA 50011 (
USDA ARS North Central Agricultural Research Laboratory, Brookings, SD (
J Econ Entomol. 2016 Aug;109(4):1872-80. doi: 10.1093/jee/tow110. Epub 2016 Jun 21.
Western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is a serious pest of corn in the United States, and recent management of western corn rootworm has included planting of Bt corn. Beginning in 2009, western corn rootworm populations with resistance to Cry3Bb1 corn and mCry3A corn were found in Iowa and elsewhere. To date, western corn rootworm populations have remained susceptible to corn producing Bt toxin Cry34/35Ab1. In this study, we used single-plant bioassays to test field populations of western corn rootworm for resistance to Cry34/35Ab1 corn, Cry3Bb1 corn, and mCry3A corn. Bioassays included nine rootworm populations collected from fields where severe injury to Bt corn had been observed and six control populations that had never been exposed to Bt corn. We found incomplete resistance to Cry34/35Ab1 corn among field populations collected from fields where severe injury to corn producing Cry34/35Ab1, either singly or as a pyramid, had been observed. Additionally, resistance to Cry3Bb1 corn and mCry3A corn was found among the majority of populations tested. These first cases of resistance to Cry34/35Ab1 corn, and the presence of resistance to multiple Bt toxins by western corn rootworm, highlight the potential vulnerability of Bt corn to the evolution of resistance by western corn rootworm. The use of more diversified management practices, in addition to insect resistance management, likely will be essential to sustain the viability of Bt corn for management of western corn rootworm.
西方玉米根萤叶甲，即Diabrotica virgifera virgifera LeConte（鞘翅目：叶甲科），是美国玉米的一种严重害虫，近期对西方玉米根萤叶甲的防治措施包括种植转基因抗虫玉米。从2009年开始，在爱荷华州及其他地区发现了对Cry3Bb1玉米和mCry3A玉米具有抗性的西方玉米根萤叶甲种群。迄今为止，西方玉米根萤叶甲种群对产生Bt毒素Cry34/35Ab1的玉米仍保持敏感。在本研究中，我们采用单株生物测定法，检测西方玉米根萤叶甲田间种群对Cry34/35Ab1玉米、Cry3Bb1玉米和mCry3A玉米的抗性。生物测定包括从观察到转基因抗虫玉米受到严重损害的田间采集的9个根萤叶甲种群，以及6个从未接触过转基因抗虫玉米的对照种群。我们发现，在从观察到单独或作为复合性状种植产生Cry34/35Ab1的玉米受到严重损害的田间采集的田间种群中，对Cry34/35Ab1玉米存在不完全抗性。此外，在大多数测试种群中发现了对Cry3Bb1玉米和mCry3A玉米的抗性。这些首次出现的对Cry34/35Ab1玉米的抗性案例，以及西方玉米根萤叶甲对多种Bt毒素具有抗性的情况，凸显了转基因抗虫玉米在应对西方玉米根萤叶甲抗性进化方面的潜在脆弱性。除了抗虫管理外，采用更多样化的管理措施可能对于维持转基因抗虫玉米用于防治西方玉米根萤叶甲的有效性至关重要。
