黄瓜霜霉病俗称“黑毛”、“跑马干”等,是黄瓜最重要的常发性病害,防治不力会造成严重损失,在哈密地区以温室黄瓜发病为重。1病害症状幼苗和成株均可发病,主要危害叶片,茎、卷须及花梗也能受害。幼苗期至结瓜期均可发病,特别是黄瓜进入成株期发病较重,一般由下部叶片向上蔓延。发病初期,在叶片正面出现浅黄色斑点,背面水浸状,湿度大时,病斑背面出现灰黑 Cucumber downy mildew, commonly known as “black hair ”, “horse race ” and so on, is the most important cucumber diseases, prevention and treatment will result in serious losses, in the Hami area to the incidence of greenhouse cucumber as the most important. 1 disease symptoms Seedlings and adults can be disease, the main hazards leaves, stems, tendrils and pedicels can also suffer. Seedling to fruiting period can be disease, especially in cucumber into the adult incidence of heavier, generally spread from the lower part of the leaves. Early onset, pale yellow spots on the front of the leaves, the back of the flooding, humidity, the back of the lesion appear gray