Reardon K T, Hellmich R L, Sumerford D V, Lewis L C, Reardon B J, Calvin D D
USDA-ARS, Corn Insects and Crop Genetics Research Unit, and Department of Entomology, Iowa State University, 102 Genetics Laboratory, Ames, IA 50011, USA.
J Econ Entomol. 2007 Aug;100(4):1129-35. doi: 10.1603/0022-0493(2007)100[1129:iopsom]2.0.co;2.
Genetically engineered corn hybrids that contain a cry gene from the bacterium Bacillus thuringiensis Berliner (Bt) are gaining popularity for controlling the corn pest Ostrinia nubilalis (Hübner). Continuous use of Bt corn, however, could select for O. nubilalis that are resistant to this corn. Monitoring for insect resistance is important, because it could help maintain the Bt technology. A possible monitoring method is to collect larval insects in commercial drying bins after harvest from Bt seed production fields. A drawback to this method is that these collections may be contaminated by insects that moved as later instars from severed non-Bt male rows into the adjacent Bt female rows. These larvae have little to no exposure to Bt toxin, resulting in possible "false positives." The objectives of this study were to first find which combination of planting and severing dates produces the least number of larvae that move from non-Bt male plants to Bt female plants and to assess O. nubilalis larval movement from severed non-Bt male rows to Bt female rows. Field studies in 2002 and 2003 were designed to simulate a hybrid seed production field. Results suggest that movement of O. nubilalis larvae from male corn is minimized when corn is planted early and male plants are severed by 2 wk post-anthesis. This reduces the likelihood of false positives by reducing the number of susceptible larvae moving between Bt and non-Bt plants. Also, larvae moved to all four female rows that were adjacent to the severed rows, but there were significantly more larvae found in the closest row compared with the other three. These results could be used to develop a monitoring program to find O. nubilalis larvae with resistance to Bt corn in field populations of O. nubilalis.
含有来自苏云金芽孢杆菌（Bt）的cry基因的转基因玉米杂交种，在防治玉米害虫欧洲玉米螟（Ostrinia nubilalis，Hübner）方面越来越受欢迎。然而，持续使用Bt玉米可能会筛选出对这种玉米具有抗性的欧洲玉米螟。监测昆虫抗性很重要，因为这有助于维持Bt技术。一种可能的监测方法是在收获后从Bt种子生产田的商业干燥仓中收集幼虫。这种方法的一个缺点是，这些收集物可能会被作为大龄幼虫从切断的非Bt雄株行移动到相邻Bt雌株行的昆虫污染。这些幼虫几乎没有接触过Bt毒素，从而可能导致“假阳性”。本研究的目的是首先找出种植和切断日期的哪种组合能使从非Bt雄株移动到Bt雌株的幼虫数量最少，并评估欧洲玉米螟幼虫从切断的非Bt雄株行到Bt雌株行的移动情况。2002年和2003年的田间研究旨在模拟杂交种子生产田。结果表明，当玉米早播且雄株在开花后2周切断时，欧洲玉米螟幼虫从雄株的移动最少。这通过减少Bt和非Bt植株之间移动的易感幼虫数量，降低了假阳性的可能性。此外，幼虫移动到了与切断行相邻的所有四行雌株，但与其他三行相比，在最靠近的一行中发现的幼虫明显更多。这些结果可用于制定一个监测计划，以在欧洲玉米螟的田间种群中找到对Bt玉米具有抗性的欧洲玉米螟幼虫。
