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一、玉米小斑病1.发病症状:玉米从幼苗到成株期均可造成较大的损失。病斑主要集中在叶片上,一般先从下部叶片开始,逐渐向上蔓延。小斑病呈圆状不规则斑块,发病区边缘呈紫红色,向内逐渐成鲜红色中心则锈状枯干。病斑初呈水浸状,后变为黄褐色或红褐色,边缘色泽较深。病斑呈椭圆形、近圆或长圆形,大小为10~15毫米,有时病斑可见2~3个同心轮纹。2.传播途径:玉米小斑病病菌以菌丝或分生孢子在病残体内越冬,在翌年温度比较适宜的56月份产生大量分生孢子,借气流或雨水传播。春玉米收获后遗留田间病残体上的分生孢子,可继续向夏玉米田传播,因此在春、夏玉米混种区,夏玉米总是比春玉米发病重。
First, the small spot disease of corn 1. Symptoms: corn seedlings to adult stage can cause greater damage. Lesions are mainly concentrated on the leaves, generally starting from the lower leaves, and gradually spread upward. Small spotted round irregular plaques, the incidence of the district was purple, gradually into the center of the bright red rusty withered. Lesions were initially immersed, after turning into brown or reddish brown, darker edge color. Lesions were oval, nearly round or oblong, the size of 10 to 15 mm, and sometimes lesions can be seen 2 to 3 concentric wheel pattern. 2. Route of transmission: Tuberculous corn germ or conidia in the diseased body in winter, in the following year the temperature is relatively suitable for a large number of 56 months conidia, by air or rain spread. After harvest of spring maize, residual conidia on the field can continue to spread to the summer maize field. Therefore, the summer maize is always more severe than the spring maize in the spring and summer maize mixed area.