College of Mathematics and Information Science, Shaanxi Normal University, Xi'an 710062, People's Republic of China.
Math Biosci. 2013 Oct;245(2):249-57. doi: 10.1016/j.mbs.2013.07.008. Epub 2013 Jul 24.
After a pest develops resistance to a pesticide, switching between different unrelated pesticides is a common management option, but this raises the following questions: (1) What is the optimal frequency of pesticide use? (2) How do the frequencies of pesticide applications affect the evolution of pesticide resistance? (3) How can the time when the pest population reaches the economic injury level (EIL) be estimated and (4) how can the most efficient frequency of pesticide applications be determined? To address these questions, we have developed a novel pest population growth model incorporating the evolution of pesticide resistance and pulse spraying of pesticides. Moreover, three pesticide switching methods, threshold condition-guided, density-guided and EIL-guided, are modelled, to determine the best choice under different conditions with the overall aim of eradicating the pest or maintaining its population density below the EIL. Furthermore, the pest control outcomes based on those three pesticide switching methods are discussed. Our results suggest that either the density-guided or EIL-guided method is the optimal pesticide switching strategy, depending on the frequency (or period) of pesticide applications.
当害虫对一种农药产生抗药性后，在不同的、不相关的农药之间进行交替使用是一种常见的管理选择，但这会引发以下问题：（1）农药使用的最佳频率是多少？（2）农药应用的频率如何影响农药抗性的进化？（3）如何估计害虫种群达到经济损害水平（EIL）的时间，以及（4）如何确定最有效的农药应用频率？为了解决这些问题，我们开发了一种新的害虫种群增长模型，该模型将农药抗性的进化和脉冲喷雾农药纳入其中。此外，我们还模拟了三种农药切换方法，即阈值条件指导、密度指导和 EIL 指导，以确定在不同条件下的最佳选择，总体目标是消灭害虫或将其种群密度维持在 EIL 以下。此外，还讨论了基于这三种农药切换方法的害虫防治效果。我们的研究结果表明，密度指导或 EIL 指导方法是最优的农药切换策略，具体取决于农药应用的频率（或周期）。
