唐山市西郊苗圃毛白杨根癌病严重。据1981年调查,1—6年生苗发病率为22.5—60％,受害苗根系不发达,树势衰弱,易感染叶部病害,并提早落叶,严重影响苗木生长。1982年经中国科学院遗传研究所张静娟副研究员分离回接试验和生理鉴 Tangshan City, western suburbs Nursery Poplar root cancer serious. According to the survey in 1981, the incidence of one to six year old seedlings was 22.5-60%. The root system of affected seedlings was underdeveloped, the tree vigor was weak, the leaf disease was easily infected, and the leaves were deciduous, which seriously affected the growth of seedlings. In 1982 by the Institute of Genetics, Chinese Academy of Sciences, Associate Professor Zhang Jingjuan separation back connection test and Physiological