Repellency and Toxicity of Eight Plant Extracts against the Western Flower Thrips, Frankliniella occidentalis

We investigated the repellency and toxicity of eight plant extracts containing celangulin, cnidium lactone, matrine, nicotine, pyrethrins, rotenone, stemonine and veratrine against the western flower thrips (Frankliniella occidentalis Pergande; Thysanoptera: Thripidae). Flowers treated with 0.05% nicotine, pyrethrins, stemonine and rotenone harbored fewer western flower thrips in two- and multiple-choice repellency bioassays. When evaluated at concentrations varying from 0.005% to 0.1% in two-choice repellency bioassays, pyrethrins and rotenone were most repellent at 0.01% to 0.1%, and nicotine was most repellent at 0.025%. Mortality was 76% with 0.1% nicotine at 48 h, 78% with 0.5% stemonine at 72 h, and 100% with 0.1% pyrethrins and 0.5% rotenone at 48 h after contact with fresh (