Li S Y, Skinner A C, Rideout T, Stone D M, Crummey H, Holloway G
Natural Resources Canada, Canadian Forest Service, Atlantic Forestry Centre, PO Box 960, Corner Brook, Newfoundland, Canada A2H 6J3.
J Econ Entomol. 2003 Feb;96(1):35-42. doi: 10.1093/jee/96.1.35.
Lethal and sublethal effects of Neemix 4.5 EC, a commercial neem preparation, on balsam fir sawfly, Neodiprion abietis (Harris), were determined in the laboratory. Larval mortality of N. abietis increased in a concentration-dependent manner, and lethal time decreased with increasing Neemix 4.5 EC concentration. Fifty percent of the larvae died after 4.6 d at a concentration of 90 ppm azadirachtin (AZA) and 12.3 d at a concentration of 0.08 ppm. Neemix 4.5 EC showed some deterrent effects to feeding site selection on N. abietis larvae at high concentrations, but not at low concentrations. Strong reduction of food intake by N. abietis larvae after exposure to Neemix 4.5 EC was demonstrated by significant reduction of frass production. Larvae fed on Neemix 4.5 EC-treated foliage at 90 ppm AZA produced only 16% as much frass as that produced by larvae fed on control foliage (0 ppm). Neemix 4.5 EC at a concentration of 0.08 ppm AZA retarded larval and pupal development. Sublethal doses significantly reduced pupal weight and adult emergence, although the sex ratio of N. abietis adults was not affected. Results indicate that sublethal effects of Neemix 4.5 EC on N. abietis may contribute greatly to the overall field efficacy.
在实验室中测定了一种商用印楝制剂Neemix 4.5 EC对香脂冷杉叶蜂（Neodiprion abietis (Harris)）的致死和亚致死效应。香脂冷杉叶蜂幼虫的死亡率呈浓度依赖性增加，致死时间随Neemix 4.5 EC浓度的增加而减少。在印楝素（AZA）浓度为90 ppm时，50%的幼虫在4.6天后死亡；在浓度为0.08 ppm时，12.3天后死亡。Neemix 4.5 EC在高浓度时对香脂冷杉叶蜂幼虫的取食位点选择有一定的驱避作用，但在低浓度时没有。暴露于Neemix 4.5 EC后，香脂冷杉叶蜂幼虫的粪便产量显著降低，表明其食物摄入量大幅减少。以90 ppm AZA处理的叶片为食的幼虫产生的粪便量仅为以对照叶片（0 ppm）为食的幼虫的16%。浓度为0.08 ppm AZA的Neemix 4.5 EC延缓了幼虫和蛹的发育。亚致死剂量显著降低了蛹重和成虫羽化率，尽管香脂冷杉叶蜂成虫的性别比例没有受到影响。结果表明，Neemix 4.5 EC对香脂冷杉叶蜂的亚致死效应可能对其田间总体防治效果有很大贡献。
