Abstract

In Morocco Culex pipiens mosquitoes cause serious nuisance in most urban areas. Control programs mainly rely on chemical insecticides, but numerous failures have been reported in the area, suggesting the development of resistant populations. In this study, we determined the resistance levels of the larval populations to two organophosphates; temephos and chlorpyriphos, commonly used in four prefectures from the regions of Rabat and Casablanca. We conducted bioassays following WHO standard procedures to calculate lethal concentrations LC₅₀ and LC₉₀ then resistance ratios by dividing values for the tested strains by those of the susceptible strain. We show that larval populations of Cx. pipiens developed resistance to temephos and chlorpyriphos in all four sites with different levels. We argue this is due to heterogeneous selection pressure triggered by local treatment practices. The high levels of resistance developed to these insecticides in the four studied areas may compromise their use in mosquito control. It hence becomes urgent to find alternatives to control larval populations of Cx. pipiens in these regions.

摘要

在摩洛哥， Culex pipiens蚊子在大多数城市地区造成严重滋扰。控制计划主要依靠化学杀虫剂，但该地区报告了许多失败，这表明抗药性种群的发展。在这项研究中，我们确定了幼虫种群对两种有机磷酸盐的抗性水平；temephos 和毒死蜱，常用于拉巴特和卡萨布兰卡地区的四个地区。我们按照 WHO 标准程序进行生物测定，计算致死浓度 LC ₅₀和 LC ₉₀，然后通过将测试菌株的值除以敏感菌株的值来计算抗性比。我们展示了Cx 的幼虫种群。花椒在所有四个地点都产生了不同水平的对temephos和毒死蜱的抗性。我们认为这是由于当地治疗实践引发的异质选择压力。在四个研究区域中对这些杀虫剂产生的高水平抗性可能会影响它们在蚊虫控制中的使用。因此，迫切需要找到控制Cx 幼虫种群的替代方法。这些地区的花椒。