白菜白斑病是一种比较普遍发生的病害,近年来又有加重的趋势。去年我区大白菜有40％左右得病,严重地块减产3～4成,直接影响了大白菜的产量和品质。白菜白斑病主要发生在秋季。在气温下降、相对湿度增高、夜露增多的条件下,此病蔓延快,危害重。它主要危害叶片,初期有灰褐色病斑,直径1～2厘米,病斑中央颜色较淡,嫩叶上病斑干枯后为白色,老叶上病斑为黄褐色,周围有略呈淡黄色轮纹1～2个。空气潮湿时,病斑背面出现淡灰色的霉 White spot cabbage white spot disease is a more common disease that has been aggravated in recent years. Last year, about 40% of Chinese cabbage got sick, severely block cut 3 to 4 percent, a direct impact on the yield and quality of Chinese cabbage. White cabbage white spot occurs mainly in autumn. In the temperature drop, the relative humidity increased, under the conditions of increased night, the spread of the disease fast, endanger heavy. It is mainly harmful to the leaves, the initial gray-brown spot, diameter of 1 to 2 cm, lesser central lesion, dry leaves on the young leaves after the white, old leaves on the lesion was brown, surrounded by slightly pale yellow 1 to 2 wheel pattern. When the air is wet, the light gray mildew appears on the back of the lesion