Instituto de Investigación e Ingeniería Ambiental (IIIA), CONICET-UNSAM, Universidad Nacional de San Martín, San Martín, Argentina.
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
Bull Entomol Res. 2022 Feb;112(1):21-28. doi: 10.1017/S000748532100050X. Epub 2021 Jul 7.
The use of chemical insecticides is the main control method for Blattella germanica worldwide. The prolonged and frequent use of insecticides produced the selection of insecticide-resistant individuals. The German cockroach is one of the most widespread urban pests in Argentina. In the last decades, resistance monitoring studies in this country demonstrated that there is a high prevalence of pyrethroid-resistant populations of B. germanica in the field. In this work, we studied the resistance mechanisms of a field-collected strain of B. germanica at toxicological, enzymatic, and molecular levels. A resistance ratio of 100 was obtained for the resistant strain when it was exposed to β-cypermethrin. The pretreatment with specific synergists (piperonyl butoxide and triphenyl phosphate) led to a significant increase in the toxicity of the pyrethroid, suggesting an involvement of oxidases and esterases in the detoxification of this insecticide. Moreover, esterase and oxidase activities in the resistant strain were 1.5-fold and 2-fold higher respectively, compared to the susceptible individuals. On the other hand, the voltage-gated sodium channel gene of the resistant cockroaches did not show nucleotidic substitutions in the domain II which are associated to knockdown resistance in this species. These results suggest that the main mechanism of resistance of the studied cockroaches' strain is metabolic, mainly due to an increase in the activity of oxidase and esterase enzymes. The results of this work in addition to other reports found in literature show that the extended use of a single active principle for cockroach control promotes the development of resistance leading to control failure in the field. In contrast, integrated pest management strategies include the use of different control tools in addition to chemical insecticides, which delay the appearance of resistance increasing the efficacy of pest control.
全世界使用化学杀虫剂是控制德国蟑螂的主要方法。杀虫剂的长期和频繁使用导致了抗药性个体的选择。德国蟑螂是阿根廷分布最广的城市害虫之一。在过去的几十年里，该国的抗性监测研究表明，在野外存在高比例对拟除虫菊酯具有抗性的德国蟑螂种群。在这项工作中，我们从毒理学、酶学和分子水平研究了田间采集的德国蟑螂种群的抗性机制。当接触到β-氯氰菊酯时，抗性品系的抗性比达到 100。用特定增效剂（增效醚和三苯基磷酸酯）预处理会显著增加拟除虫菊酯的毒性，这表明氧化酶和酯酶参与了这种杀虫剂的解毒。此外，与敏感个体相比，抗性品系的酯酶和氧化酶活性分别提高了 1.5 倍和 2 倍。另一方面，抗性蟑螂的电压门控钠离子通道基因在与该物种击倒抗性相关的 II 结构域中没有核苷酸取代。这些结果表明，研究中蟑螂种群的主要抗性机制是代谢性的，主要是由于氧化酶和酯酶活性的增加。除了文献中其他报道的结果外，这项工作的结果表明，单一活性物质在蟑螂控制中的长期使用会促进抗性的发展，导致田间控制失败。相比之下，综合虫害管理策略包括除化学杀虫剂外还使用不同的控制工具，这会延迟抗性的出现，从而提高虫害控制的效果。
