葡萄霜霉病是葡萄的主要病害之一,它发生普遍,为害严重,特别是苗期更易感染。主要为害叶片,也为害嫩梢、花蕾、幼果等柔嫩部分。被害叶片提早脱落,影响树势和正常结果。症状:植株叶片受侵染后,首先出现不规则的水浸状小斑点,以后发展成黄褐色多角形斑块,天气潮湿时,叶子背面便长出霜状霉层,是此病的主要特征。幼果也易受害,先是由绿变为红褐色,然后果内逐渐腐烂,最后干缩脱落。 Grape downy mildew is one of the main diseases of grapes. It is common and serious damage, especially in seedling stage. The main damage leaves, but also damage young shoots, buds, young fruit and other soft parts. Viciae leaves off early, affecting the tree vigor and normal results. Symptoms: After the leaves of the plants are infested, the first irregular spots of water-soaked polygons develop into yellow-brown polygons. When the weather is wet, the frost-like mildew layer grows on the back of the leaves and is the main feature of the disease . Young fruit is also vulnerable, first turned from green to reddish-brown, and then the fruit gradually decayed, and finally dried shrink off.