title: Highly variable insect control efficacy of Tephrosia vogelii chemotypes.
abstract: Tephrosia vogelii has been used for generations as a pest control material in Africa. Recently, two chemotypes have been reported based on the occurrence (chemotype 1) or absence (chemotype 2) of rotenoids. This could have an impact on the efficacy and reliability of this material for pest control. We report that chemotype 2 has no pesticidal activity against Callosobruchus maculatus Fabricius (family Chrysomelidae) and that this is associated with the absence of rotenoids. We present a first report of the comparative biological activity of deguelin, tephrosin, α-toxicarol, and sarcolobine and show that not all rotenoids are equally effective. Tephrosin was less toxic than deguelin which was less active than rotenone, while obovatin 5-methyl ether, the major flavonoid in chemotype 2 was inactive. We also report that in chemotype 1 the occurrence of rotenoids shows substantial seasonal variation.
authors.affiliation: Natural Resources Institute, University of Greenwich , Central Avenue, Chatham Maritime, Kent, ME4 4TB, U.K.
authors.forename: Steven R
authors.initials: SR
authors.lastname: Belmain
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Amoah
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Nyirenda
authors.forename: John F
authors.initials: JF
authors.lastname: Kamanula
authors.forename: Philip C
authors.initials: PC
authors.lastname: Stevenson
mesh_terms: D000349:Africa; D000818:Animals; D001517:Coleoptera; D005419:Flavonoids / Q000032:analysis; D007300:Insect Control; D007306:Insecticides / Q000032:analysis*; D018515:Plant Leaves / Q000737:chemistry; D012402:Rotenone / Q000031:analogs & derivatives / Q000032:analysis; D031304:Tephrosia / Q000737:chemistry* / Q000145:classification*; D048889:Weevils
chemical_list: D005419:Flavonoids; D007306:Insecticides; D012402:Rotenone; C107676:deguelin