U.S. Department of Agriculture, Agricultural Research Service, National Center for Agricultural Utilization Research, Crop BioProtection Research Unit, 1815 N University St., Peoria, IL, 61604, USA.
U.S. Department of Agriculture, Agricultural Research Service, National Center for Agricultural Research, Functional Foods Research Unit, 1815 N University St., Peoria, IL, 61604, USA.
Exp Appl Acarol. 2022 Feb;86(2):299-312. doi: 10.1007/s10493-022-00692-0. Epub 2022 Jan 25.
The repellency and toxicity of a CO-derived cedarwood oil (CWO) was evaluated against actively questing unfed nymphs of four species of hard ticks: Amblyomma americanum (L.), Dermacentor variabilis (Say), Ixodes scapularis Say, and Rhipicephalus sanguineus (Latreille). Using a vertical climb bioassay for repellency, nymphs of these species avoided a CWO-treated filter paper in proportional responses to treatment concentrations. At 60 min of exposure, I. scapularis nymphs were most sensitive with 50% repellency concentration (RC) of 19.8 µg cm, compared with RC of 30.8, 83.8 and 89.6 µg cm for R. sanguineus, D. variabilis and A. americanum, respectively. Bioassays determined the lethal concentration for 50% (LC) and 90% (LC) mortality of nymphs exposed to CWO in treated vials after 24- and 48-h exposure. After 24 h exposure, the LC values were 1.25, 3.45 and 1.42 µg cm and LC values were 2.39, 7.59 and 4.14 µg cm for D. variabilis, I. scapularis and R. sanguineus, respectively, but had minimal effect on A. americanum. After 48 h exposure, the LC values were 4.14, 0.78, 0.79 and 0.52 µg cm, and LC values were 8.06, 1.48, 1.54 and 1.22 µg cm for A. americanum, D. variabilis, I. scapularis and R. sanguineus, respectively. The repellency of CWO on tick species decreased with time. The repellency and toxicity bioassays demonstrated concentration-dependent responses of tick nymphs to the oil, indicating the potential of the CO-derived cedarwood oil be developed as an eco-friendly repellent and/or acaricide.
对源自 CO 的雪松木油（CWO）的驱避性和毒性进行了评估，评估对象为四种硬蜱的活跃觅食若虫：美洲钝缘蜱（A. americanum）（L.）、变色革蜱（D. variabilis）（Say）、肩突硬蜱（I. scapularis）Say 和血红扇头蜱（R. sanguineus）（Latreille）。使用垂直爬升生物测定法进行驱避性测试，这些物种的若虫对处理浓度的比例反应避免了 CWO 处理的滤纸。在 60 分钟的暴露时间内，I. scapularis 若虫最敏感，50%驱避浓度（RC）为 19.8 µg cm，而 R. sanguineus、D. variabilis 和 A. americanum 的 RC 分别为 30.8、83.8 和 89.6 µg cm。生物测定法确定了暴露于 CWO 处理小瓶中 24 小时和 48 小时后 50%（LC）和 90%（LC）死亡率的致死浓度。暴露 24 小时后，D. variabilis、I. scapularis 和 R. sanguineus 的 LC 值分别为 1.25、3.45 和 1.42 µg cm，LC 值分别为 2.39、7.59 和 4.14 µg cm，但对 A. americanum 的影响最小。暴露 48 小时后，A. americanum、D. variabilis、I. scapularis 和 R. sanguineus 的 LC 值分别为 4.14、0.78、0.79 和 0.52 µg cm，LC 值分别为 8.06、1.48、1.54 和 1.22 µg cm。随着时间的推移，CWO 对蜱种的驱避性降低。驱避性和毒性生物测定表明，蜱若虫对油的浓度具有依赖性反应，表明源自 CO 的雪松木油具有作为环保型驱避剂和/或杀蜱剂开发的潜力。
