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为害症状 :此病主要危害叶片 ,发病初期叶片上出现黄褐色小斑 ,后期数个小斑融合一起 ,呈圆形或受叶脉所限呈多角形的病斑。潮湿时 ,叶背生有灰色的霜状物 ,干燥时 ,病斑中间部分容易破裂。病害严重时 ,叶片早期枯黄脱落。分布区域 :全国各地发病特点 :此病为真菌引起 ,病菌在
Harmful symptoms: The disease is the main hazard leaves, early onset of yellowish brown patches appear on the leaves, the latter part of the merger of several small spots were round or limited by the polygons vein lesions. When wet, leaves back to a gray cream-like, dry, easy to break the middle part of the lesion. When the disease is serious, the leaves turn yellow early. Distribution area: incidence characteristics across the country: the disease caused by fungi, bacteria in the