Lu Ping, Davis Richard F, Kemerait Robert C
University of Georgia, Department of Plant Pathology, P.O. Box 748, Tifton, GA 31793, USA.
J Nematol. 2010 Jun;42(2):96-100.
The southern root-knot nematode (Meloidogyne incognita) is a major parasite of cotton in the U.S., and management tactics for this nematode attempt to minimize population levels. We compared three post-harvest practices for their ability to reduce nematode population levels in the field, thereby reducing initial nematode population for the next year's crop. The three practices tested were: 1) chemical defoliation before harvest plus cutting cotton stalks after harvest, 2) chemical defoliation plus applying a herbicide to kill plants prior to cutting the stalks, and 3) chemical defoliation without cutting stalks. Experiments were conducted in both the greenhouse and in the field. The greenhouse experiments demonstrated that M. incognita reproduction (measured as egg counts and root gall rating indices) was significantly greater when stalks were not cut. Cutting stalks plus applying herbicide to kill cotton roots did not significantly reduce nematode reproduction compared to cutting stalks alone. In field experiments, cutting stalks reduced egg populations and root galling compared to defoliation without stalk cutting. In a greenhouse bioassay which used soil from the field plots, plants grown in soil from the defoliation only treatment had greater root gall ratings and egg counts than in the stalk cutting plus herbicide treatment. Therefore, we conclude that cutting cotton stalks immediately after harvest effectively reduces M. incognita reproduction, and may lead to a lower initial population density of this nematode in the following year.
南方根结线虫（Meloidogyne incognita）是美国棉花的主要寄生线虫，针对这种线虫的防治策略旨在尽量降低其种群数量。我们比较了三种收获后的处理方法，看它们降低田间线虫种群数量的能力，从而减少下一年作物种植时的初始线虫种群数量。测试的三种处理方法分别是：1）收获前化学脱叶并在收获后砍除棉花秸秆；2）化学脱叶并在砍除秸秆前施用除草剂杀死植株；3）化学脱叶但不砍除秸秆。在温室和田间都进行了试验。温室试验表明，不砍除秸秆时，南方根结线虫的繁殖（以卵数量和根瘤评级指数衡量）显著更高。与仅砍除秸秆相比，砍除秸秆并施用除草剂杀死棉花根系并没有显著降低线虫繁殖。在田间试验中，与不砍除秸秆只进行脱叶相比，砍除秸秆降低了卵数量和根瘤形成。在一项使用田间试验地块土壤的温室生物测定中，仅经过脱叶处理的土壤中生长的植株，其根瘤评级和卵数量比经过砍除秸秆并施用除草剂处理的土壤中生长的植株更高。因此，我们得出结论，收获后立即砍除棉花秸秆能有效降低南方根结线虫的繁殖，并可能导致下一年该线虫的初始种群密度降低。
