在温室大棚生产条件下,由于空气温度高,一旦黄瓜病株出现后,12~14天即可蔓延到全温室大棚植株发病,造成提早拉秧,一般减产10%~30%,重者达50%。一、病症主要表现在叶片上,苗期子叶出现褪绿点,逐渐呈枯黄色不规则病斑,在潮湿条件下,子叶背面产生灰黑色霉层,子叶很快变黄枯干。成株期,真叶染病,叶缘或叶背面出现水浸状斑点,早晨尤为明显,病斑扩大后受叶脉限制,呈多角形黄绿色, In greenhouse production conditions, due to the high temperature of the air, once the emergence of cucumber disease, 12 to 14 days can be spread to the greenhouse plant disease, resulting in early Ra seedlings, the general reduction of 10% to 30% of the weight of up to 50 %. First, the disease is mainly manifested in the leaves, seedling cotyledons appear chlorotic spots, gradually yellowish irregular lesions, in wet conditions, cotyledons produce gray mold layer, cotyledons quickly turn yellow dry. Adult plants, true leaf disease, leaf margin or leaf back surface flooding-like spots, especially in the morning, lesion expanded by the veins restricted, polygonal yellow-green,