title: Mosquito (Diptera: Culicidae) repellency field tests of essential oils from plants traditionally used in Laos.
abstract: Essential oils of Hyptis suaveolens (Lamiaceae), Croton roxburghii (Euphorbiaceae), and Litsea cubeba (Lauraceae) were tested in the field near Vientiane city, Lao PDR, on humans for repellent activity against mosquitoes. Landing mosquitoes were collected and later identified. The most abundant mosquitoes captured belonged to the genera Armigeres, Culex, and Aedes. All the plant oils tested at concentrations of 1.7 microg/cm(2), 3.3 microg/cm(2), and 6.3 microg/cm(2) were significantly more mosquito repellent than the negative control. Croton oil was significantly repellent against mosquitoes of the three genera at the highest (6.3 microg/cm(2)) concentration tested. Litsea oil was significantly repellent against Armigeres at all (1.7 microg/cm(2), 3.3 microg/cm(2), and 6.3 microg/cm(2)) concentrations tested. Hyptis oil was significantly repellent against Armigeres at 3.3 microg/cm(2) and 6.3 microg/cm(2) and against Culex at 1.7 microg/cm(2) and 6.3 microg/cm(2). The oils were analyzed for chemical content of volatiles, mainly terpenes. Main constituents were beta-pinene, sabinene, and 1,8-cineol from oils of the green parts of H. suaveolens; alpha-pinene, beta-pinene, and alpha-phellandrene from fresh bark of C. roxburghii; and alpha-pinene, beta-phellandrene, sabinene, and 1,8-cineol from fresh fruits of L. cubeba.
authors.affiliation: Department of Systematic Biology, Uppsala University, Norbyvigen 18D, SE-75236 Uppsala, Sweden.
authors.forename: Chanda
authors.initials: C
authors.lastname: Vongsombath
authors.forename: Katinka
authors.initials: K
authors.lastname: Pålsson
authors.forename: Lars
authors.initials: L
authors.lastname: Björk
authors.forename: Anna-Karin
authors.initials: AK
authors.lastname: Borg-Karlson
authors.forename: Thomas G T
authors.initials: TG
authors.lastname: Jaenson
mesh_terms: D000818:Animals; D029802:Croton / Q000737:chemistry; D009033:Culicidae; D003671:DEET; D005260:Female; D006801:Humans; D031331:Hyptis / Q000737:chemistry; D007302:Insect Repellents / Q000032:analysis*; D032862:Litsea / Q000737:chemistry; D008297:Male; D009032:Mosquito Control; D009822:Oils, Volatile / Q000737:chemistry*; D010938:Plant Oils / Q000737:chemistry; D011156:Population Density; D055815:Young Adult
chemical_list: D007302:Insect Repellents; D009822:Oils, Volatile; D010938:Plant Oils; D003671:DEET