一、发病症状玉米小斑病从苗期到成熟期均可发生,以玉米抽雄后发病重。主要危害叶片、叶鞘和苞叶。叶片上病斑比大斑病小得多,但病斑数量多。初为水浸状,以后变为黄褐色或红褐色,边缘颜色较深,椭圆形、圆形或长圆形,病斑密集时常互相连接成片,形成较大型枯斑。多雨潮湿天气,有时在病斑上可看到黑褐色霉层。多从植株下部叶片先发病,向上蔓延、扩展。 First, the incidence of symptoms of maize leaf spot from the seedling to maturity can occur, the incidence of corn tasselling heavy. The main hazards leaves, leaf sheaths and bracts. The leaf spot is much smaller than the spotted leaf spot but the number of spots is large. Early as a flooded, later into a brown or reddish brown, dark edge of the color, oval, round or oblong, dense spots often connected to each other into pieces, forming a larger spot. Rainy and wet weather, sometimes seen on the lesion dark brown moldy layer. More from the lower leaves of plants first disease, spread upward, expansion.