A Study on the Tick Repellent Effect of Blending Essential Oil for Developing of Natural Ticks Repellents

In this study, an experiment was conducted to measure the tick repellent efficacy through the synergy effect according to the type and ratio of blending essential oil. The subjects were adults and nymphs of the Haemaphysalis longicornis, and the repellent efficacy was measured using the filter paper bioassay method. Based on the past research, citronella oil, geranium oil, vetiver oil, and neem oil were selected as a single treatment experiment since their repellent efficacy was confirmed. The first experiment revealed that the repellent efficacy of citronella oil and geranium oil were high. Afterwards, in order to investigate the synergy effect on tick repellent efficacy, experimental group was consisted of neem seed oil (carrier oil) that was blended with citronella and geranium oil, at a ratio of 1:1, 2:1, and 17:3 (15%). Also, negative control group was composed of ethanol that was blended with citronella and geranium oil at the same ratio of experimental group. As a result, the blending of citronella and neem seeds showed higher repellent efficacy in all blending ratios than the blending of geranium and neem seeds. In adult ticks, blending ratio of citronella and neem seeds was 1:1 and 17:3, showed the most significant difference of repellent efficacy. In nymph ticks, when the blending ratio of citronella and neem seed was 1:1 and 17:3, the repellent efficacy was the same as that of the positive control commercial repellent. In conclusion, it was confirmed that both nymph and adults ticks showed higher repellent efficacy when blended than single treatment. In this study, the synergy effect of the blending of citronella and neem seeds on the tick repellent effect has a high potential to replace synthetic repellents.