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在所有为害贮存烟草并能造成严重损失的昆虫种类中 ,烟草甲虫Lasiodermaserricorne(F .)和烟草粉螟Ephestiaelutella(H¨ubner)是原烟及加工后烟草的 2种主要害虫。收获后烟草害虫的防治主要通过消毒、害虫监测以及磷化氢熏蒸来实现 ,而储烟害虫已对磷化氢产生抗药性 ,并已有防治失败的实例报道 ,而熏蒸也越来越受到相关法规的制约。一些生物防治剂如苏云金杆菌Bacillusthuringiensis(Bt) ,因对环境无害而有可能替代化学防治。Bt是一种细菌 ,在芽孢形成阶段能够产生杀虫晶体蛋白。Bt用作植食性害虫的生防制剂已有 4 0多年的历史。Bt产生的杀虫晶体蛋白对几个目的昆虫具有特有的生物活性 ,可对昆虫的取食产生影响。我们实验室进行了广泛的研究并在世界范围内开展了调查 ,对仓储烟草中的Bt进行评价 ,现已证实了以前的研究结果 ,即Bt是自然发生的叶面微生物群落中的一部分。已从烟草上分离出几个Bt菌株并进行了特征描述 (DNA和蛋白质图谱 )。已通过胃毒的方法对所分离的菌株以及 2个商业产品对烟草甲幼虫的杀虫活性进行了测定。在长达 30个月的贮存期内 ,对已调制烟叶上的Bt孢子及其晶体蛋白的稳定性进行了分析。Bt处理过的烟叶制成卷烟样品评吸后 ,处理与对照卷烟无显著性差异。尽管在规定的时间及剂量情?
Tobacco beetle Lasiodermaserricorne (F.) And tobacco stem borer Ephestiaelutella (Hüubner) are the two major pests of both raw and processed tobacco in all the insect species that are responsible for storing tobacco and causing serious damage. Post-harvest control of tobacco pests is mainly achieved through disinfection, monitoring of pests and fumigation with phosphine, while storage-stored pests have become resistant to phosphine and have reported instances of control failure, and fumigation has become more and more relevant Legislation constraints. Some biocontrol agents, such as Bacillus thuringiensis (Bt), are likely to replace chemical control because they are not harmful to the environment. Bt is a bacterium that produces insecticidal crystal proteins during the sporulation phase. Bt has been used as a biocontrol agent for phytophagous pests for more than 40 years. Insecticidal crystal proteins produced by Bt have specific biological activity against several insect species of interest and can affect insect feeding. Extensive research conducted in our laboratories and worldwide surveys to evaluate Bt in warehousing tobacco has now confirmed previous findings that Bt is part of a naturally occurring foliar microbial community. Several Bt strains have been isolated from tobacco and characterized (DNA and protein profiles). The insecticidal activity of the isolated strains and two commercial products against N. tabaci larvae has been determined by gastric toxicity. During the storage period of up to 30 months, the stability of Bt spores and their crystal proteins on the conditioned tobacco was analyzed. Bt treated tobacco leaves made of cigarette samples after smoking, the treatment and control cigarettes no significant difference. Although in the prescribed time and dose situation?