霜霉病是大棚葡萄生产中的一种重要病害，常普遍发生，尤其在高温情况下，病害更加严重，损失较大。一、危害症状葡萄霜霉病主要危害叶片，也能侵害嫩梢、花和幼果等幼嫩组织。叶片发病初期，叶面为半透明水渍状斑点，以后逐渐扩大，呈现黄色或褐色不规则病斑，边缘界限不明显 Downy mildew is an important disease in the production of greenhouse grapes, and it is common to occur frequently, especially in the case of high temperature, the disease is more serious and the loss is greater. First, the harm symptoms Grape downy mildew main hazard leaves, but also against young shoots, flowers and young fruits and other young organizations. In the early stage of leaf emergence, the leaf surface was semitransparent water-like spots, and then gradually enlarged, showing yellow or brown irregular spots with marginal boundary not obvious