Submitted to: Journal of the Mosquito Control Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/19/2005
Publication Date: 7/1/2006
Citation: Zhu, J., Zeng, X., Ma, Y., Liu, T., Qian, K., Han, Y., Xue, S., Tucker, B., Schultz, G., Coats, J. 2006. Comparisons of adult repellency and larvicidal activity of plant essential oils against mosquitoes. Journal of the Mosquito Control Association. 35:249-257 Interpretive Summary: The control of mosquito vectors of disease has become more difficult because of the development of resistance to insecticides and synthetic repellents. Presently, the most commonly used and effective mosquito repellent is DEET. However, recent concerns about DEET have been reported because significant amounts can be absorbed through the skin, especially among children and elderly people. We have evaluated five natural plant essential oils and demonstrated that these plant essential oils not only repel the mosquito from human skin, but also kill mosquito larvae. This information will enable scientists to develop natural mosquito repellents as alternative to DEET, to prevent mosquito bites. It will also enable industry to provide the general public a safer and more efficient mosquito control product.
Technical Abstract: The repellency and larvicidal activity of five plant essential oils including thyme oil, catnip oil, amyris oil, eucalyptus oil and cinnamon oil were studied on three mosquito species, Aedes albopictus, Ae. aegypti and Culex pipiens pallens. The repellency of the selected essential oils to female blood-starved Ae. albopictus when applied to human skin was examined in the laboratory and was compared to that of DEET. Catnip oil appeared to be the most effective and provided 6-hour protection at both concentrations tested (23.425 'g/cm2 and 468 'g/cm2). Thyme oil had the highest effectiveness in repelling this mosquito, but the repellency only lasted for 2 hours. When evaluating larvicidal activity of these essentials oils against 4th instar larvae of above three mosquito species in the laboratory, we demonstrated that amyris oil had the most inhibitory effect with the LC50 values in 24 hr were 58 'g/ml (LC90 = 72 'g/ml) to Ae. aegypti, 78 'g/ml (LC90 = 130 'g/ml) to Ae. albopictus, and 77 'g/ml (LC90 = 123 'g/ml) to Cx. pipiens pallens. The future applications using these natural product essential oils in mosquito control were also discussed.