| Ticks belonging class of arthropods are blood-sucking body surface parasitisms,which can transmit a variety of viruses,bacteria,protozoa and other pathogens,and are a great threat to human health and animal husbandry.Rhipicephalus haemaphysaloides is a three-host tick,which is a common tick species in the Eastern Ocean and widely distributed in China.It can cause a variety of diseases,such as Canine Gbesiasis,tick-borne fever,and bovine edge worm disease.In this study,the killing effect of six plant essential oils on the different periods of sickle fan-head tick was tested by touch killing experiment and fumigation experiment,and the active plant essential oils were screened out,and half of the lethal concentrations(Median lethal concentration,LC50)were determined.At the same time,the composition analysis of 6 plant essential oils was carried out by gas chromatography and liquid chromatography.The findings are as follows:1.Compositional analysis of plant essential oils shows that thymol,carvacrol,eugenol and cinnamaldehyde provided by Centree are all single essential oils greater than99%pure,and the composite essential oil 135 is a composite essential oil composed of three high-purity single-product essential oils of cinnamaldehyde,carvacrol and thymol,and the composite essential oil enhancement type is an essential oil consisted of four high purity single-product essential oils of thymol,carvacrol,eugenol and cinnamaldehyde.It can be seen that the most important role of various types of essential oils in the poisoning and avoidance of ticks is the phenols and aldehydes.2.The Scylla falciparum tick was reared in captivity in the laboratory at 25±1°C and RH≥90%in a biochemical incubator in the dark to successfully complete the entire life history of the tick and provide sufficient experimental animals for the experiment.3.In the touch killing experiment of plant essential oils,Thymol,compound essential oil reinforced and cinnamaldehyde pose the most significant effects on Rhipicephalus haemaphysaloides with,LC50of 3.12,3.71 and 4.09 mg/m L,respectively;In the touch killing experiment of Rhipicephalus haemaphysaloides,the three plant essential oils with the most significant killing effect were compound essential oil reinforced.Thymol and complex essential oils 135 with LC50of 6.91,7.55 and 7.95mg/m L,respectively.In the fumigation experiment of plant essential oils on Rhipicephalus haemaph ysaloides,the effects on Rhipicephalus haemaphysaloides were significant in killing carvacrol,thymol and cinnamaldehyde;the effects on Rhipicephalus haemaphysalo ides were cinnamaldehyde,thymol and complex essential oils;the effects on Rhipi cephalus haemaphysaloides were cinnamaldehyde,thymol and complex essential oil s;The effects of killing the hunger ticks of Rhipicephalus haemaphysaloides were the compound essential oil-enhanced,eugenol and carvacrol;in addition,the conce ntrated essential oil-enhanced type had a significant egg-laying inhibition effect on Rhipicephalus haemaphysaloides,and the compound essential oil-enhanced type had a significant effect on the hatching inhibition effect of Rhipicephalus haemaphysal oides eggs.4.In the avoidance experiment,the effect of DEET was the most significant,and the avoidance effect of cinnamaldehyde,compound essential oil-enhanced and thymol was significant,and half of the avoidance concentrations EC50（Median effective concentration）were 1.37 mg/m L,1.96 mg/m L and 2.29 mg/m L,respectively.The above studies provide data for the development and application of new tick killers,fumigants and avoidants,and provide theoretical basis and technical reference for tick control. |
