Abstract As a consequence of the widespread use of insecticides against insect pests in grain warehouses and in the food industry, insecticide resistance has greatly increased among these species all over the world. Nonetheless, insecticide resistance in stored grain insects in Egypt was little studied. Therefore, our study aimed to forecast infestation risks and determine the insecticide resistance level in Egyptian populations of the main insect pests of stored grains. To achieve this goal, we surveyed the populations of stored-product insects in wheat in two different sites in the Alexandria governorate (Egypt) between June and August 2017. Moreover, insecticide resistance levels in Egyptian populations of Tribolium castaneum (Herbst) and Sitophilus oryzae (L.) collected from wheat storage facilities (granaries and flour mills) in Alexandria governorate were also determined. Three contact insecticides, namely malathion, pirimiphos-methyl and cypermethrin, were tested. Tarsal contact bioassays on filter paper were carried out on adults following FAO methods and concentration-mortality lines were estimated to determine the resistance ratios for each insecticide and population. The data from the monitoring of insects revealed that T. castaneum and S. oryzae were the most common species infesting wheat in both Alexandria granaries and mills. Populations of S. oryzae were generally more resistant to malathion than the populations of T. castaneum. However, T. castaneum populations were more resistant to pirimiphos-methyl than the S. oryzae populations. Both populations of T. castaneum and S. oryzae were susceptible to cypermethrin. The detected levels of insecticide resistance indicate that this phenomenon takes place and should be a concern in Egyptian populations of T. castaneum and S. oryzae requiring monitoring and design of resistance management practices.

中文翻译：

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埃及红面甲虫 Tribolium castaneum (Herbst) 和米象 Sitophilus oryzae (L.) 的储粮害虫流行率和杀虫剂抗性

摘要 由于在粮食仓库和食品工业中广泛使用杀虫剂来防治害虫，世界各地这些物种的杀虫剂抗药性大大增加。尽管如此，埃及储存谷物昆虫的杀虫剂抗性研究很少。因此，我们的研究旨在预测埃及储粮主要害虫种群的侵染风险并确定其对杀虫剂的抗药性水平。为实现这一目标，我们于 2017 年 6 月至 8 月期间在亚历山大省（埃及）的两个不同地点调查了小麦中贮藏昆虫的种群。此外，埃及赤霉病（Tribolium castaneum，Herbst）和 Sitophilus oryzae 种群的杀虫剂抗性水平(L. ) 还确定了从亚历山大省的小麦储存设施（粮仓和面粉厂）收集。测试了三种接触性杀虫剂，即马拉硫磷、甲基嘧啶磷和氯氰菊酯。按照粮农组织的方法对成虫进行滤纸接触生物测定，并估计浓度-死亡率线以确定每种杀虫剂和种群的抗性比。来自昆虫监测的数据显示，T. castaneum 和 S. oryzae 是亚历山大粮仓和磨坊中最常见的感染小麦的物种。S. oryzae 种群通常比 T. castaneum 种群对马拉硫磷具有更强的抗性。然而，T. castaneum 种群比 S. oryzae 种群对甲基嘧啶磷具有更高的抗性。T. castaneum 和 S. oryzae 对氯氰菊酯敏感。检测到的杀虫剂抗药性水平表明，这种现象发生了，并且应该引起需要监测和设计抗药性管理实践的埃及 T. castaneum 和 S. oryzae 种群的关注。