Agricultural and Applied Economics, University of Wisconsin, Madison, WI, USA.
Applied Economics, University of Minnesota, St. Paul, MN, USA.
Pest Manag Sci. 2021 Jan;77(1):273-284. doi: 10.1002/ps.6016. Epub 2020 Aug 16.
Farmers around the world have used Bt maize for more than two decades, delaying resistance using a high-dose/refuge strategy. Nevertheless, field-evolved resistance to Bacillus thuringiensis (Bt) toxins has been documented. This paper describes a spatially explicit population genetics model of resistance to Bt toxins by the insect Ostrinia nubilalis and an agent-based model of farmer adoption of Bt maize incorporating social networks. The model was used to evaluate multiple resistance mitigation policies, including combinations of increased refuges for all farms, localized bans on Bt maize where resistance develops, area-wide sprays of insecticides on fields with resistance and taxes on Bt maize seed for all farms. Evaluation metrics included resistance allele frequency, pest population density, farmer adoption of Bt maize and economic surplus.
The most effective mitigation policies for maintaining a low resistance allele frequency were 50% refuge and localized bans. Area-wide sprays were the most effective for maintaining low pest populations. Based on economic surplus, refuge requirements were the recommended policy for mitigating resistance to high-dose Bt maize. Social networks further enhanced the benefits of refuges relative to other mitigation policies but accelerated the emergence of resistance.
These results support using refuges as the foundation of resistance mitigation for high-dose Bt maize, just as for resistance management. Other mitigation policies examined were more effective but more costly. Social factors had substantial effects on the recommended management and mitigation of insect resistance, suggesting that agent-based models can make useful contributions for policy analysis.
全世界的农民已经使用 Bt 玉米超过二十年，通过高剂量/避难所策略延迟了抗药性的产生。然而，田间已经出现了对苏云金芽孢杆菌（Bt）毒素的抗性。本文描述了一个用于评估多种抗性缓解策略的空间显式种群遗传学模型，该模型用于评估多种抗性缓解策略，包括增加所有农场的避难所、在抗性出现的地方局部禁止 Bt 玉米种植、对有抗性的田地进行大面积喷洒杀虫剂以及对所有农场的 Bt 玉米种子征税。评估指标包括抗性等位基因频率、害虫种群密度、农民对 Bt 玉米的采用率和经济剩余。
维持低抗性等位基因频率最有效的缓解策略是 50%的避难所和局部禁止。大面积喷洒是维持低害虫种群最有效的方法。基于经济剩余，避难所要求是缓解高剂量 Bt 玉米抗性的推荐政策。社会网络进一步增强了避难所相对于其他缓解策略的效益，但加速了抗性的出现。
这些结果支持将避难所作为高剂量 Bt 玉米抗性缓解的基础，就像抗性管理一样。其他被研究的缓解策略更有效，但成本更高。社会因素对昆虫抗性的推荐管理和缓解有重大影响，这表明基于主体的模型可以为政策分析做出有用的贡献。
