1症状表现玉米发病后,多数叶片由下而上表现青枯症状,少数为黄枯症状,茎基变软变褐,果穗下垂,穗柄柔韧,不易掰下。有的病株茎基1~3节变褐色,剖开茎基维管束间隙常见白色菌丝或红色霉状物。按病情发展速度和症状特点,可分为急性型和普通型。急性型发病速度快,往往在1~2d内全株迅速失水枯萎,似开水烫,叶片突然出现青灰色、枯萎的早死现象,呈青枯状;普通型发病较慢,5~10d内全株才表现症状,整株叶片自茎 1 Symptoms After the onset of corn, the majority of leaves showed wilt symptoms from the bottom up, a small number of symptoms of yellowish-brown, soft brown base, sagging ears, flexible handle, not easy to break off. Some diseased stem cells 1 to 3 brown, cut open the base of the vascular bundle common white mycelium or red mildew. According to the speed of disease development and symptoms, can be divided into acute and common type. Acute incidence of fast, often within 1 ~ 2d the whole plant rapidly dehydrated wilt, like boiling water, the leaves suddenly blue gray, withered premature death phenomenon, was brown; common onset is slow, within 5 ~ 10d Strains show symptoms, the whole plant leaves from the stem