Repellency to the sand fly, Phlebotomus papatasi (Scopoli), by essential oils listed as active ingredients for minimum risk pesticide products in the United States

Phlebotomus papatasi , a vector of Leishmania protozoans causing leishmaniasis in tropical and subtropical regions of Africa, Europe, the Middle East, and Southern Asia, poses a significant threat to local populations, and deployed U.S. military personnel. Leishmaniasis is prevented by minimizing exposure to sand fly bites by mechanical barriers, pesticide-impregnated uniforms, and personal repellents such as DEET. Insecticides are utilized, but effectiveness of available insecticide is limited, and dependent on application method and environmental conditions. Risk of human toxicity limits insecticide use as indoor residual sprays. This highlights the need to develop safe and effective repellents and insecticides for use in integrated sand fly control programs. Many essential oils are repellent or insecticidal and several are conditionally exempt from United States Environmental Protection Agency registration as minimum risk pesticide products under the Code of Federal Regulations, Title 40, Part 152.25, paragraph f. This study evaluated essential oils listed as U.S. minimum risk pesticide products against P . papatasi in comparison to DEET. Lemongrass, corn mint, cinnamon, citronella, clove, and spearmint oils and their components (trans-cinnamaldehyde, citronellal, citral, geraniol, N-propyl d-camphor lactam, EZ-nepetalactone, citronellal, diethyl (2-methylally) phosphonate and menthol) exhibited greater repellency to P. papatasi than DEET, and menthol, citronellal, and citral were insecticidal. Listing of these essential oils as minimum risk pesticides indicates they pose little risk to human health or the environment. Further testing of these essential oils is warranted to protect humans and animals from bites and disease-causing agent transmission by sand flies and other insect disease vectors.