Abstract
Ylang-ylang oil (YYO) from Cananga odorata (Lam.) Hook.f. & Thomson and star anise oil (SAO) from Illicium verum Hook.f. were tested at four concentrations 0.05, 0.1, 0.2, 0.4 µl/cm2. Mortality rates were obtained by counting dead nymphs at 30-min intervals during the first 5 h after the start of exposure and then at 24, 48 and 72 h. Mortality increased with increasing oil concentration and time of exposure. The two highest concentrations of YYO (0.2, 0.4 µl/cm2) gave maximum lethal concentrations (LC) of 50 and 95% mortality after 4.5 h exposure. Mortality of 95% was obtained after 24 h with the next highest dose (0.1 µl/cm2), whereas LC95 required 3 days with the lowest YYO (0.05 µl/cm2). The lethal effect time (LT) was correlated with the duration of exposure, with a significant effect at 0.4 μl YYO/cm2 after 3 h’ (LT50 = 3.2 h, LT95 = 4.3 h). In contrast, only the highest concentration of SAO, 0.4 µl SAO/cm2, showed increasing mortality with time of exposure. This reached LT50 after 10 h and LT95 after 24 h. However, with the lower concentration (0.2 µl/cm2) 50% mortality was reached after 24 h and 100% at 72 h. At to the lowest concentration of SAO (0.1 µl/cm2), 67% mortality after 48 h. The study indicates that YYO and SAO exhibit strong acaricidal properties against nymphs of I. ricinus and suggest that both YYO and SAO should be evaluated as potentially useful in the control of ticks.
Highlights
Ticks (Acari: Ixodoidea) are obligatory blood-sucking arthropods and are among the most harmful ectoparasites and most important disease vectors of domestic and wild animals (Randolph 1998)
The lethal concentrations at different exposure times to ylang-ylang oil (YYO) were calculated at 4.5 h
I. ricinus seems to have increased in abundance in many locations in Northern Europe during the last decades (Gray 1984, 1991; Mejlon and Jaenson 1993; Jaenson et al 2012a, b), which has led to an increase in the number of human cases of tick-borne diseases (Lindgren and Jaenson 2006; Jaenson et al 2012a, b)
Summary
Ticks (Acari: Ixodoidea) are obligatory blood-sucking arthropods and are among the most harmful ectoparasites and most important disease vectors of domestic and wild animals (Randolph 1998). Due to its widespread distribution, catholic feeding habits and because of its willingness to bite humans, I. ricinus is the most important European vector of many pathogens, such as tick-borne encephalitis virus (TBEV), the protozoan parasite Babesia divergens (M’Fadyean and Stockman 1911) and several bacteria, e.g. Anaplasma phagocytophilum, several rickettsiae and the Lyme borreliosis spirochetes. These and other tick-transmitted infections might be controlled and/or reduced by minimizing human contact with high-risk tick-infested habitats. A simple and cheap method of protecting humans and domestic animals against ticks is needed
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call