湘西黑藤精油的杀虫活性

为探明湘西黑藤精油对白纹伊蚊的卵和幼虫、小菜蛾3龄幼虫、菜粉蝶3龄幼虫、斜纹夜蛾3龄幼虫、棉蚜和烟蚜无翅成蚜的杀虫活性,通过浸渍法、夹毒叶碟法、点滴法和玻片载蚜法测定了该精油对上述昆虫的生物活性.结果表明,湘西黑藤精油对白纹伊蚊的卵没有毒杀活性,但对其初孵幼虫和4龄幼虫具有较好的毒杀活性,24 h的LC50值分别是11.3 mg/L和38.5 mg/L;在质量浓度为500 mg/L时,精油虽然对3种供试鳞翅目幼虫没有触杀和胃毒活性,但有较弱的拒食活性,24 h的拒食率分别是38.6%,17.1%和6.7%;对棉蚜和桃蚜的毒杀活性也较差,24 h的LC50值分别是213.1 mg/L和235.1 mg/L.

Insecticidal activities of the essential oils extracted from the stems of Derris cavaleriei

In order to probe into the insecticidal activities of the essential oils extracted from the stems of Derris cavaleriei (EODC) against the eggs and larvae of Aedes albopictus, the adult of both Aphis gossypii and Myzus persicae, the larvae of Plutella xylostella, Pieris rapae and Prodenia litura, bioassay were conducted to measure the above-mentioned six species of insect pests by means of sandwich slide-dip and topical application. The results showed that EODC hadn't exhibited insecticidal activity to the mosquito eggs but possessed the insecticidal activity against the mosquito larvae, with the LC_(50) values being 11.3 mg/L to the neonate larvae and 38.5 mg/L to the fourth-instar larvae at 24 h after treatment. EODC had exhibited antifeedant activity at the concentration of 500 mg/L, with the respective antifeeding rate being 38.6%, 17.1% and 6.7% against the larvae of P. Xylostella, P. Rapae and P. Litura with no contact poison and stomach poison to them. EODC had exhibited weak toxicity against A. Gossypii and M. Persicae, and respective LC_(50) values were 213.1 mg/L and 235.1 mg/L. The above-mentioned results indicated that EODC contained various kinds of bioactive compounds, which could be used as a potential botanical mosquitio control agents.