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【背景】螺旋粉虱是新入侵海南省的严重为害经济作物及园林苗木的害虫。目前,植物源杀虫剂因具有高效和环境友好等特性而被广泛用于害虫防治中。【方法】采用喷雾法和药膜接触法分别测定了9种植物性杀虫剂对螺旋粉虱的毒力。【结果】在供试的9种植物性杀虫剂中,除虫菊素和鱼藤酮对螺旋粉虱成虫的毒力最强,24h的LC50分别为2.56和34.15mg·L-1;印楝素和苦瓜叶提取物的毒力次之,LC50分别为158.36和311.02mg·L-1。除虫菊素对螺旋粉虱若虫和卵也有一定的触杀作用,LC50分别为61.42和77.39mg·L-1。将印楝素和鱼藤酮分别与除虫菊素以1:1的比例混合,对螺旋粉虱成虫的毒力表现出明显的增效作用,其共毒系数(CTC)分别为193.11和224.35。【结论与意义】除虫菊素、鱼藤酮、印楝素和苦瓜叶提取物对螺旋粉虱均具有较强的毒性;印楝素或鱼藤酮与除虫菊素(1:1)的混合物不仅能增强触杀效果,而且能延缓害虫抗药性的产生。
【Background】 The whitefly is a newly-invaded pest of the severely damaged cash crops and garden seedlings in Hainan Province. Currently, botanical insecticides are widely used in pest control because of their high efficiency and environmental friendliness. 【Method】 The toxicity of 9 kinds of botanical insecticides against B. tabaci were determined by spray method and membrane contact method respectively. 【Result】 Pyrethrins and rotenone had the strongest virulence to adults of B. tabaci, with LC50 of 2.56 and 34.15 mg · L-1, respectively, among the 9 plant-based pesticides tested. Azadirachtin and bitter melon The virulence of leaf extracts was second, with LC50 of 158.36 and 311.02 mg · L -1, respectively. Pyrethrins also had certain contact effects on nymphs and eggs of Helicoverpa armigera, with LC50 values of 61.42 and 77.39 mg · L -1, respectively. Mixing azadirachtin and rotenone respectively with pyrethrin at a ratio of 1: 1 showed obvious synergistic effect on the virulence of adults of Bemisia tabaci, with the co-toxicity coefficients (CTC) of 193.11 and 224.35, respectively. 【Conclusion and Significance】 Pyrethrins, rotenone, azadirachtin and bitter melon leaf extracts have strong toxicity to B. tabaci. Mixtures of azadirachtin, rotenone and pyrethrin (1: 1) can not only enhance the contact effect, And can delay the emergence of pest resistance.