黄瓜褐斑病,多从黄瓜盛瓜期开始发病,一般中、下部叶片先发病,向上发展。初期在叶面生出灰褐色小斑点,逐渐扩展成大小不等的圆形或近圆形边缘不太整齐的淡褐色或褐色病斑。后期病斑中部颜色变浅,有时呈灰白色,边缘灰褐色。湿度大时病斑正、背面均生稀疏的淡灰褐色霉状物。严重时病斑相融合,叶片枯黄。黄瓜霜霉病,一般大棚前沿发病重,症状明显,叶片上有黄褐色病斑,受叶脉限制,湿度大时叶背面有灰色或黑色霉层。 Cucumber brown spot disease, cucumber melon from the onset of onset, usually the lower part of the first disease, upward development. Early on the leaf surface gives birth to small brown spots, gradually expanded into round or near-circular size is not very neat edge of the brown or brown lesions. Late lesion lighter central color, sometimes pale, the edge of beige. When the humidity is large, the lesion is sparsely grayish brown moldy on the back. Serious plaque fusion, yellow leaves. Cucumber downy mildew, the incidence of general front of the greenhouse heavy, obvious symptoms, leaves have brown spots, restricted by the veins, humidity, leaf back when gray or black mildew.