杨树腐烂病又名烂皮病,是杨树毁灭性的枝干病害,在我县普遍发生,北京杨、大关杨、箭干杨受害最严重(见表)。经四年观察,发病规律是:四月下旬开始发病,5—6月是发病盛期,7月停止为害。8月上旬形成第二次发病高峰,一直为害到秋末冬初。病菌在病斑上过冬,翌年春 Poplar rot disease, also known as rotten disease, is a devastating poplar branch disease, occurs in our county, Beijing Yang, Yang Guan mark, arrow dry Yang most affected (see table). After four years of observation, the incidence of law is: the onset of disease in late April, 5-6 months is the peak incidence, July to stop the damage. In early August the second peak incidence, has been harmed until late autumn and early winter. Germs in the spot on the winter, the following spring