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1988年以来,济南市历城区白菜黑腐病发生普遍,蔓延迅速,危害严重,一般病株率为25%～35%,重病地达60%以上,有的甚至绝产,严重威胁白菜生产。1989～1991年作者对该病的症状及病原菌的致病性进行了测定,初步观察结果如下。一、症状观察人工接种或自然病土,出土子叶染病呈水渍状,后变苗枯,根髓变黑。成株期引起明显的叶斑及黑脉。病叶叶斑先从叶缘向内扩展,形成“V”字形黄褐色枯斑,叶斑周围组织淡黄色,与健部界限不明显。有时病菌沿叶脉向里扩展,形成大块黄褐色斑,或网状黑脉,
Since 1988, black rot disease of cabbage in Licheng District of Jinan City has been widespread and spread rapidly with serious damage. The average disease strain rate is 25% -35%, serious disease rate is more than 60%, and some are even absolutely dead, which seriously threatens the production of cabbage. From 1989 to 1991, the author tested the symptoms of the disease and the pathogenicity of pathogens. The preliminary results are as follows. First, the symptoms observed artificial inoculations or natural soil, soil-cotyledon disease was water-like symptoms, change after the seedling withered, root marrow blackening. Adult caused obvious leaf spot and black veins. The diseased leaves leaf spot expanded inwardly from the leaf margin, forming the “V” shape yellowish brown spot, the tissue around the leaf spot was yellowish, and the boundary between the Ministry of Health was not obvious. Sometimes the germs spread inward along the veins, forming chunks of brown patches or reticulate black veins,