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 LC₅₀ 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.

中文翻译：

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柠檬香柏中的精油对the虫血ema（Haariphysalis longicornis）（Acari：Ixodidae）的死亡率和形态的影响。

血红蛋白是东亚，澳大利亚和新西兰最流行的tick种之一，已被认为是多种病原体的媒介。这项研究评估了柠檬柏（Cymbopogon citratus（lemongrass））精油对未进食的H. longicornis的体外杀螨效果使用成虫和若虫浸没测试，以及幼虫小包测试。使用六种浓度，分别具有10、20、30、40、50和60 mg / mL（成人和若虫）的三个重复浓度，以及2.5、5、10、20、40和80 mg / mL（幼虫）的浓度组（50％乙醇）。成人和若虫在50 mg / mL时的死亡率分别为98％和100％，在60 mg / mL时为95％和100％，而在40和80 mg / mL时，幼虫死亡率分别为94％和96％。成年，若虫和幼虫的死亡率以剂量依赖性方式显着增加。LC ₅₀对于成人，若虫和幼虫，分别为29.21（95.5％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，牙槽窝的感觉根基脱节，表皮裂缝，气孔阻塞和中肠萎缩。这些结果表明，由于柠檬柠条精油具有很高的杀螨效果，因此它可能是一种很好的环保替代控制策略，可对抗壁虱等壁虱。