title: Excito-repellency of essential oils against an Aedes aegypti (L.) field population in Thailand.
abstract: An investigation of the behavioral responses of Aedes aegypti (= Stegomyia aegypti) to various concentrations of essential oils (2.5, 5, and 10%) extracted from hairy basil (Ocimum americanum Linn), ginger (Zingiber officinale Roscoe), lemongrass (Cymbopogon citratus Stapf), citronella grass (Cymbopogon nardus Rendle), and plai (Zingiber cassumunar Roxb) were performed using an excito-repellency test chamber. Results showed that Ae. aegypti exhibited varying levels of escape response in both the contact and noncontact chambers in response to different essential oils. The magnitude of the behaviors changed in a dose-response fashion depending on the percent volume to volume concentration of oil used. A 2.5% concentration of hairy basil oil produced a significantly greater escape response compared to the other extracts at the same concentration (P< 0.05). Oils of ginger, lemongrass, and citronella produced stronger irritant and repellent responses at the median 5% concentration compared to the lowest and highest concentrations. There was marked suppression of escape for both contact and noncontact tests using 10% concentrations of hairy basil, lemongrass, and citronella, with high knockdown for all three oils after 30 min. Hairy basil and lemongrass had the highest insecticidal activity to Ae. aegypti, with LC50 values of 6.3 and 6.7 percent, respectively. We conclude that the essential oils from native plants tested, and likely many other extracts found in plants, have inherent repellent and irritant qualities that should to be screened and optimized for their behavior-modifying properties against Ae. aegypti and other biting arthropods of public health and pest importance.
authors.affiliation: Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok 10900, Thailand; Center for Advanced Studies for Agriculture and Food, Kasetsart University Institute for Advanced Studies, Kasetsart University, Bangkok 10900, Thailand. faasthc@ku.ac.th.
authors.forename: Wasana
authors.initials: W
authors.lastname: Boonyuan
authors.forename: John P
authors.initials: JP
authors.lastname: Grieco
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Bangs
authors.forename: Atchariya
authors.initials: A
authors.lastname: Prabaripai
authors.forename: Siripun
authors.initials: S
authors.lastname: Tantakom
authors.forename: Theeraphap
authors.initials: T
authors.lastname: Chareonviriyaphap
mesh_terms: D000330:Aedes / Q000187:drug effects*; D000818:Animals; D031743:Cymbopogon / Q000737:chemistry; D020939:Zingiber officinale / Q000737:chemistry; D007306:Insecticides / Q000737:chemistry / Q000494:pharmacology; D009822:Oils, Volatile / Q000737:chemistry* / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry* / Q000494:pharmacology*; D013785:Thailand
chemical_list: D007306:Insecticides; D009822:Oils, Volatile; D010936:Plant Extracts
keywords: Aedes aegypti; Behavior; Thailand; excito-repellency; plant extracts