近年来京郊蔬菜苗期病害有所发展,为害逐年加重。根据我们调查,主要有猝倒病、立枯病和生理病害——沤根。现将三个病害的症状、发生规律及防治技术介绍如下。为害症状(一)猝倒病:病苗茎基部呈水渍状,病斑浅黄绿色,但很快转为黄褐色,并缢成线状。病害发展迅速,以致子叶尚未萎蔫,幼苗便倒伏而死,京郊农民称此病为“卡脖子”。苗床开始时只有少数的幼苗发 In recent years, the suburbs of Beijing vegetable seedling diseases have developed, increasing harm each year. According to our investigation, there are mainly damping-off disease, damping-off disease and physiological disease - gall root. Now the symptoms of the three diseases, the occurrence of the law and prevention techniques are as follows. Harm symptoms (A) damping-off disease: The seedling stem base was water-like, yellowish green lesions, but soon turned yellowish brown, and 缢 into a linear. The rapid development of disease, so that cotyledons have not yet wilted, seedlings will lodging and died, the suburbs of Beijing farmers said the disease as “card neck.” There are only a few seedlings in the beginning of the seedbed