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英文文献：Optimal Control Of Pest Resistance To Transgenic Crop Varieties-转基因作物抗虫害最优控制
英文文献作者：Grimsrud, Kristine M.,Huffaker, Ray G.
英文文献摘要：
Transgenic corn varieties entered the market in 1996. These plant varieties carry a gene from the soil bacterium Bacillus thuringiensis kurstaki, Bt, that makes the plant produce a toxin deadly to the pest insect European Corn Borer (ECB) Ostrinia nubilalis (Hübner). Since ECB may build up genetic resistance to this toxin, the growers of transgenic corn varieties are required to plant a portion of their field (refuge) with regular corn. This requirement is expected to prolong the efficiency of Bt corn in combating the ECB because some non-resistant pests can survive in the refuge, and thereby dilute the build-up of resistance in the overall pest population. A fixed refuge size of 20 percent is the currently recommended "rule-of-thumb" by the Environmental Protection Agency (EPA). Past work has searched for an economically-optimal refuge size utilizing discrete-time simulation approaches in which refuge size is treated as an exogenous parameter whose optimal value is found through numerical iteration. The objective of this work is to fine-tune parametric refuge specifications by formulating a bioeconomic model capable of endogenously determining the optimal trajectory of refuge sizes over time via an analytical optimal-control rule. The model will provide novel comparative statics/dynamics results demonstrating the sensitivity of the optimal trajectory to important economic and biological parameters.
转基因玉米品种于1996年进入市场。这些植物品种携带一种来自土壤细菌苏云金芽孢杆菌(Bt)的基因，这种基因可以使植物产生一种毒素，对有害昆虫欧洲玉米螟(ECB)鸵鸟(Hubner)致命。由于欧洲央行可能会建立对这种毒素的基因抗性，转基因玉米品种的种植者被要求在他们的部分农田(避难所)上种植普通玉米。这一要求预计将延长Bt玉米对抗欧洲央行的效率，因为一些不具有抗性的害虫可以在庇护所中存活，从而稀释害虫种群中抗性的积累。20%的固定避难面积是美国环境保护局(EPA)目前推荐的“经验法则”。以往的工作是利用离散时间模拟方法来寻找经济上最优的避难面积，其中避难面积被视为一个外生参数，其最优值是通过数值迭代得到的。这项工作的目标是通过建立一个生物经济模型来微调参数化的避难所规格，这个生物经济模型能够通过解析的最优控制规则内源性地决定避难所大小随时间的最佳轨迹。该模型将提供新的比较静态/动力学结果，证明最优轨迹对重要的经济和生物参数的敏感性。
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