一、玉米粗缩病症状:玉米粗缩病是一种由灰飞虱传播的病毒病,近几年呈逐年加重发生趋势,对玉米生产造成严重影响。玉米整个生育期都可感染发病,以苗期受害最重。在玉米5~6片叶即可显症,心叶不易抽出且变小,可作为早期诊断的依据。防治:(1)选用抗、耐病品种。不同品种之间病害发生情况存在一定差异,郑单958、鲁单981、鲁单984等品种发病较轻,病株率在5%以下。(2)农 First, the symptoms of corn sickening: Corn sliver is a virus transmitted by the brown planthopper disease, in recent years showed a trend of increasing year by year, have a serious impact on corn production. The whole growth period of corn can be infected with the disease, the heaviest damage in seedling stage. 5 to 6 leaves in the corn can be obvious disease, heart leaves can not be easily extracted and smaller, can be used as a basis for early diagnosis. Prevention: (1) selection of anti-disease-resistant varieties. There are some differences between the disease occurrences of different varieties, Zheng Dan 958, Lu Dan 981, Lu Dan 984 and other varieties less susceptible, the diseased rate below 5%. (2) Farmers