title: Toxicity and feeding deterrence of crude toxin extracts of Lecanicillium (Verticillium) lecanii (Hyphomycetes) against sweet potato whitefly, Bemisia tabaci (Homoptera: Aleyrodidae).
abstract: Crude toxins [toxin(V3450) and toxin(Vp28,) extracted from Lecanicillium (Verticillium) lecanii (Zimmermann) Gams & Zare strain V3450 and Vp28 respectively] were tested for contact toxicity, feeding deterrence and repellent activity against the sweet potato whitefly, Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae). Both toxins showed ovicidal activity to eggs, with LC(50) values of 447 and 629 mg L(-1) respectively. Nymphs of B. tabaci were the most susceptible stages (LC(50) values were calculated at 111 mg L(-1) for toxin(V3450) and 216 mg L(-1) for toxin(Vp28)), and adults were the second most susceptible stages (48 h LC(50) values were calculated at 178 mg L(-1) for toxin(V3450) and 438 mg L(-1) for toxin(Vp28)). Applied to seedlings at a concentration of 400 mg L(-1), the toxins significantly (P < 0.001) reduced the hatching of whitefly eggs and the subsequent survival rate of the nymphs, and the emergence and fecundity of the progeny adults. Both toxins exhibited repellent activity at low concentration (100 mg L(-1)), with repellency index (RI) values of 0.645 for toxin(V3450) and 0.642 for toxin(Vp28), and antifeedant activity at high concentration (1000 mg L(-1)) to adults, with antifeedant index (AFI) values of 0.713 for toxin(V3450) and 0.749 for toxin(Vp28). The results of the present study demonstrate the toxicity, repellence and antifeedant properties of the fungi metabolite toxins on B. tabaci, which might develop as environmentally friendly plant protectant(s).
authors.affiliation: Institute of Applied Ecology, Key Laboratory of Biopesticide and Chemical Biology, MOE, Fujian Agriculture and Forestry University, Fuzhou, China. wangliande@yahoo.com
authors.forename: Liande
authors.initials: L
authors.lastname: Wang
authors.forename: Jian
authors.initials: J
authors.lastname: Huang
authors.forename: Minsheng
authors.initials: M
authors.lastname: You
authors.forename: Xiong
authors.initials: X
authors.lastname: Guan
authors.forename: Bo
authors.initials: B
authors.lastname: Liu
mesh_terms: D000818:Animals; D045424:Complex Mixtures / Q000302:isolation & purification / Q000633:toxicity; D005247:Feeding Behavior / Q000187:drug effects*; D006430:Hemiptera / Q000187:drug effects* / Q000502:physiology; D006999:Hypocreales / Q000737:chemistry*; D007302:Insect Repellents / Q000494:pharmacology; D007306:Insecticides / Q000494:pharmacology*; D027723:Ipomoea batatas / Q000633:toxicity; D009183:Mycotoxins / Q000302:isolation & purification / Q000494:pharmacology*; D009758:Nymph / Q000502:physiology; D018515:Plant Leaves / Q000633:toxicity; D012098:Reproduction / Q000187:drug effects; D018675:Toxicity Tests
chemical_list: D045424:Complex Mixtures; D007302:Insect Repellents; D007306:Insecticides; D009183:Mycotoxins