Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China.
Exp Appl Acarol. 2020 May;81(1):37-50. doi: 10.1007/s10493-020-00485-3. Epub 2020 Apr 3.
Haemaphysalis longicornis is one of the most prevalent tick species across eastern Asia, Australia, and New Zealand, and has been implicated as a vector of several pathogenic agents. This study evaluated the in vitro acaricidal efficacy of Cymbopogon citratus (lemongrass) essential oil on unfed H. longicornis using the adult and nymph immersion test, and the larval packet test. Six concentrations with three replications each of 10, 20, 30, 40, 50 and 60 mg/mL (adults and nymphs) were used, and 2.5, 5, 10, 20, 40 and 80 mg/mL (larvae), with control group (50% ethanol). The adult and nymph mortality rates were 98 and 100% at 50 mg/mL, and 95 and 100% at 60 mg/mL, respectively, whereas the larval mortality rate was 94 and 96% at 40 and 80 mg/mL, respectively. Mortality of adult, nymph and larva increased significantly in a dose-dependent manner. The LC for adult, nymph, and larva, were 29.21 (95% confidence interval 25.90-32.58), 28.18 (23.78-32.25), and 28.06 (25.57-30.90) mg/mL, respectively. Scanning electron microscopy and light microscopy revealed a disjointed sensilla base from the sockets, cuticular cracks, blocked aeropyles, and shrinking of the midgut. These results showed that C. citratus essential oil could be a good eco-friendly alternative control strategy against ectoparasites like ticks due to its high acaricidal efficacy.
长角血蜱是分布于东亚、澳大利亚和新西兰最普遍的蜱种之一，已被证实为几种病原体的传播媒介。本研究采用成蜱和若蜱浸渍试验及幼虫浸染包被试验，评估了香茅草（柠檬草）精油对未吸血长角血蜱的体外杀蜱效果。使用了 6 个浓度，每个浓度设 3 个重复，浓度分别为 10、20、30、40、50 和 60 mg/mL（成蜱和若蜱），以及 2.5、5、10、20、40 和 80 mg/mL（幼虫），以 50%乙醇作为对照组。在 50 mg/mL 时，成蜱和若蜱的死亡率分别为 98%和 100%，在 60 mg/mL 时，死亡率分别为 95%和 100%，而幼虫在 40 和 80 mg/mL 时的死亡率分别为 94%和 96%。死亡率随剂量呈显著的依赖性增加。成蜱、若蜱和幼虫的 LC 分别为 29.21（95%置信区间 25.90-32.58）、28.18（23.78-32.25）和 28.06（25.57-30.90）mg/mL。扫描电子显微镜和光学显微镜显示，感觉器基部从插座上分离、角质层出现裂缝、气门被堵塞以及中肠收缩。这些结果表明，香茅草精油可能是一种针对蜱等外寄生虫的良好的环保替代控制策略，因为它具有高效的杀蜱效果。
