粘虫是一种迁飞性、暴发性的杂食性害虫。7月中下旬以来,东北、华北地区降雨频繁、温度适中,气候条件特别适宜粘虫的集中迁入和发生为害。8月上旬,内蒙古通辽和赤峰,河北廊坊、唐山、保定、沧州、秦皇岛,北京,天津,山西晋中等地三代幼虫相继暴发,面积之大、范围之广、密度之高为近10年罕见, Mythimna separata is a migratory, fulminant omnivore pest. Since the middle and late July, northeast and north China have frequent rainfall and moderate temperature, and climatic conditions are particularly suitable for the concentrated migration and occurrence of armyworm. In early August, the three generation larvae of Tongliao and Chifeng in Inner Mongolia, Langfang in Hebei, Tangshan, Baoding, Cangzhou, Qinhuangdao, Beijing, Tianjin and Shanxi were successively outbreaks with large area, wide range and high density, which were rare for nearly 10 years.