论文部分内容阅读
近几年来,大白菜“系统性坏死”在全国为害严重,受害面积不断扩大.1986年陕西、河南、河北、山东等省大面积受害,致使冬季大白菜供应紧张.该病的主要症状是:苗期、莲座期发病时,首先在植株一侧的叶柄、叶片上产生黑褐色坏死斑点,叶脉变褐、坏死,根部同一侧也变褐色,脆而易折,减缓或停止生长,以致死亡.而另一侧短期内仍能维持生长,从而形成半边系统性坏死症状,极易感染其它病菌而引起腐烂;
In recent years, Chinese cabbage “systemic necrosis ” seriously damaged in the country, the victim area continues to expand in 1986, Shaanxi, Henan, Hebei, Shandong and other provinces suffer a large area, resulting in tight supply of winter Chinese cabbage. The main symptoms of the disease Is: seedling stage, rosette period of onset, first in the plant petiole, leaves dark brown necrosis spots, veins brown, necrosis, the same root also brown, crisp and easy to fold, slow or stop growing, resulting in While the other side can still maintain short-term growth, resulting in half of the systemic necrosis symptoms, easily infected with other pathogens cause decay;