夏玉米粗缩病在夏玉米苗期开始发生,6 月下旬至7月中旬发病达到高峰。一般田块病从地边开始发生,病株率在21%-28%,重病田可高达 78%。其发病症状是茎叶扭缠在一起,形成直棍状,叶片雌雄不能伸出,全田玉米高低不齐,发病中心区向四周扩散,轻者有小雌穗,但是授粉不良,穗小缺粒严重, Summer maize nodules began to occur in summer maize seedling stage, the incidence peaked in late June to mid July. The general field disease began to occur from the ground, the strain rate of 21% -28%, severe disease can be as high as 78%. Its symptoms are stem twisting together, the formation of straight stick, the male and female leaves can not be extended, the whole field of corn alien, the center of the spread to the surrounding areas, the light of a small female, but poor pollination, spike small Seriously grainy,