ABSTRACT Aedes aegypti, is a major vector of several human diseases such as dengue, yellow fever, chikungunya and Zika virus. Multiple strategies are adopted for its control including eradication of mosquito breeding sites by improving water storage and solid waste disposal as well as treating breeding sites with chemical insecticides. However, continuous use of insecticides has resulted in development of insecticide resistance in Ae. aegypti. This study explores the potential biocontrol of Ae. aegypti by the use of commercial entomopathogenic nematodes, namely Heterorhabditis bacteriophora, H. downesi, H. megidis, Steinernema carpocapsae, S. feltiae and S. kraussei. The pathogenic effect of nematodes (concentrations 10, 250, 500 and 1,000 infective juveniles (IJs)) was assessed against third instar Ae. aegypti in multi-well culture plates for 3 days. The evaluated nematode species were pathogenic to Ae. aegypti, however, their virulence varied significantly. Heterorhabditis bacteriophora and S. carpocapsae were most virulent causing 90-100% mortality at 100 IJs per larva, whereas H. megidis and S. kraussei showed least virulence causing 40-60% mortality. Heterorhabditis downesi and S. feltiae had intermediate virulence. Third instar Ae. aegypti indiscriminately overfeed nematodes triggering melanisation but ingested nematodes overcome the defence system resulting in killing the larvae and reproduced within them. Some of the nematodes were melanised, suggesting a strong humoral defence response by Aedes, nevertheless, with variable degree of melanisation. The melanisation did not stop nematode from multiplying and killing Aedes larvae and thus, they have potential to be developed into a novel strategy for Ae. aegypti control.

中文翻译：

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商业昆虫病原线虫的滥用导致埃及伊蚊幼虫死亡：基孔肯雅热、登革热和黄热病的病媒控制潜力

摘要 埃及伊蚊是登革热、黄热病、基孔肯雅热和寨卡病毒等多种人类疾病的主要传播媒介。采取多种策略进行控制，包括通过改善蓄水和固体废物处理以及用化学杀虫剂处理蚊子繁殖地来根除蚊子繁殖地。然而，连续使用杀虫剂导致了伊蚊的杀虫剂抗性的发展。埃及人。本研究探讨了 Ae 的潜在生物防治。通过使用商业昆虫病原线虫，即 Heterorhabditis bacteriophora、H. downesi、H. megidis、Steinernema carpocapsae、S. Feeliae 和 S. kraussei，对埃及伊蚊进行检测。针对三龄 Ae 评估了线虫（浓度为 10、250、500 和 1,000 只感染性幼虫 (IJ)）的致病作用。aegypti 在多孔培养板中培养 3 天。评估的线虫种类对 Ae 具有致病性。然而，埃及伊蚊的毒力差异很大。Heterorhabditis bacteriophora 和 S. carpocapsae 的毒性最强，在每只幼虫 100 IJ 时导致 90-100% 的死亡率，而 H. megidis 和 S. kraussei 的毒性最低，导致 40-60% 的死亡率。Heterorhabditis downesi 和 S. Feeliae 具有中等毒力。三龄 Ae。埃及伊蚊不分青红皂白地过度喂食线虫，引发黑化，但摄入的线虫克服了防御系统，导致幼虫死亡并在其中繁殖。一些线虫被黑化，表明伊蚊有强烈的体液防御反应，但黑化程度不一。黑化并没有阻止线虫繁殖和杀死伊蚊幼虫，因此，它们有可能被开发成 Ae 的新策略。埃及控制。