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一、危害部位晚疫病在马铃薯生长季节的任何时候都可造成植株叶、叶柄及茎的死亡,在田间还可以侵染薯块,使其在田间或贮藏期间腐烂。二、症状识别叶部的症状最初表现出圆形或不规则形水渍状病斑,在植株下部叶尖或叶缘开始发生。天气潮湿时,病斑很快扩大,形成轮廓不明显的褐色坏死区,在病健交界处,有一圈2～3厘米白色稀疏的霉状物,叶背更为明显。严重时病斑扩展到叶柄和茎上,产生褐条状斑,长短不等,使叶片萎蔫,干枯下垂,最后整株变为焦黑,潮湿时呈湿腐状。
First, the harmful parts of the late blight at any time during the potato growing season can cause plant leaves, petiole and stem death, in the field can also invade the potato pieces to make it rot during the field or during storage. Second, the symptoms Identify the symptoms of the leaves initially showed a circular or irregular shaped water stain-like lesions, the lower tip of the leaves or leaves began to occur. When the weather is wet, the lesion expands rapidly to form a brown necrotic area with an insignificant outline. At the junction of the diseased and healthy areas, there is a circle of 2 to 3 centimeters of white sparse mildew and the leaves are more pronounced. In severe cases, the lesion extended to the petiole and stem, producing brown stripes, varying in length, making the leaves wilting, dry and drooping, finally the whole plant became coke black, humid rot corrupt.