Submitted to: Medical and Veterinary Entomology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/21/2009
Publication Date: 8/13/2009
Publication URL: hdl.handle.net/10113/32633
Citation: Zhu, J.J., Zeng, X., Berkebile, D.R., Du, H., Tong, Y., Qian, K. 2009. Efficacy and Safety of Catnip (Nepeta cataria) as a Novel Filth Fly Repellent. Medical and Veterinary Entomology. 23:209-216. Interpretive Summary: Catnip (Nepeta cataria) is an herbaceous mint native to Eurasia and North Africa, and is also found in most of North America. Essential oil of catnip has been recently reported as an alternative mosquito repellent both topically and spatially. The present paper shows that it also repels the two major urban and livestock pest fly species, the house fly, Musca domestica, and the stable fly (also called dog fly or beach fly that is of considerable importance to people, pets and the tourist industry), Stomoxys calcitrans effectively. Although the demonstrated effectiveness of repellency against biting flies and mosquitoes, the toxicity of this natural product repellent has not yet been evaluated. In comparisons of the published acute toxicity data on DEET, Picaridin, and para-menthane-3,8-diol (three most widely used mosquito repellents) to the results from the currently study, catnip oil appears to be the least toxic. However, catnip oil may cause skin irritation due to the observed redness of the applied skin area after the treatment.
Technical Abstract: The essential oil of catnip (Nepeta cataria) has recently been reported as an alternative mosquito repellent on mosquitoes both topically and spatially. The present study reports that catnip oil resulted in an average repellency of 96% in feeding against stable fly (Stomoxys calcitrans) and 79% to the house fly (Musca domestica) using a newly developed in vitro bioassays. Toxicity test was further performed to provide a broad spectrum on safety of using catnip oil as a biting insect repellent. The acute oral LD50 of catnip oil was 3160 mg/kg and 2710 mg/kg body weight (BW) in female and male rats. The acute dermal LD50 was > 5000 mg/kg BW. The acute inhalation LD50 was observed > 10,000 mg/L. The primary skin irritation test on New Zealand white rabbits showed that catnip oil is a moderate irritant. Catnip oil was classified as practically non-irritating to the eye. Compared to other EPA approved repellents, catnip oil is considered relatively safe to use.