论文部分内容阅读
杨树苗木在春天定植后,由于根系还未恢复吸收机能,树体较弱,很容易导致溃疡病的发生,尤其是北京杨和小敏旱等品种更易发生此病,往往造成春季绿化失败。 1993年春,我校园定植三年生小敏旱杨树苗木800余株,定植两周后检查,成活率达100％。4月初发现有死株现象,树体表面出现水渍状病疤,黄水外溢,手按病疤较软,汁液沿病疤向四周蔓延,诊断为杨树溃疡病,且病情发展较快,病情严重,
Poplar seedlings planted in the spring, because the root system has not yet restored the absorption function, the tree is weak, it can easily lead to the occurrence of ulcer disease, especially Beijing Yang and small susceptible varieties are more likely to cause the disease, often resulting in green failure in spring. In the spring of 1993, more than 800 small-size poplar seedlings were planted on the campus of my school. After two weeks of planting, the survival rate reached 100%. Early April found dead phenomenon, the surface of the tree appeared water-like scar, yellow spill, hand scar by the soft scar, the juice spread along the scars around the diagnosis of poplar canker disease, and the rapid development of the disease, serious condition,