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一、病害识别萝卜霜霉病是一种真菌侵染引起的病害,在萝卜整个生育期都可造成危害。其典型症状是:叶背面出现灰白色霜状霉层。子叶期发病,叶片无明显病斑,只在叶片背面生长白色霜状霉层,苗期可造成苗叶及幼茎变黄枯死。病害从植株下部向上扩展,叶面初现不规则褪绿黄斑,后渐扩大为多角形黄褐色病斑,大小3～7毫米,湿度大时,叶背或叶两面长出白
First, the disease identification Radish downy mildew is a disease caused by fungal infection, radish throughout the growth period can cause harm. The typical symptoms are: milky white moldy mildew appears on the back of the leaf. Cotyledon onset, leaves no obvious spots, only in the back of the leaves grow white cream-like mold layer, seedling can cause seedlings and young stems turn yellow dead. The disease spreads upwards from the lower part of the plant. The leaf surface begins to irregularly chlorosis the macula and gradually enlarges into a polygonal brownish spot with a size of 3-7 mm. When the humidity is high,