一、症状 该病以危害叶片为主，偶尔危害叶鞘，初生病斑呈圆形或椭圆形退绿斑点，淡黄色，后扩大呈卵圆形、椭圆形或梭形病斑，病斑中央枯白色至乳白色，外围有褐色环并带有退绿晕圈，严重时全株叶片密布病斑，病斑偶有联合，造成全叶枯死。受害地块减产２０％～６０％。 二、 First, the symptoms of the disease to harm the leaves, and occasionally endanger the sheath, the primary lesion was round or oval green spots, light yellow, enlarged after oval, oval or spindle-shaped lesions, the central lesion withered White to milky white with a brown ring around the back with a halo retreated, in severe cases the leaves of the whole plant dense spots, occasionally combined lesions, resulting in full-blown dead. Land damage reduction of 20% to 60%. two,