一、烂根冬季,受气温低、地温低和光照不足、育苗床内湿度大等因素的影响,蔬菜在育苗期常发生烂根现象,影响幼苗的正常生长。一般症状表现为根部呈铁锈色腐烂,幼苗出土后生长缓慢,不发新根,有的甚至停止生长,叶色呈灰绿色,并逐渐变黄,造成全株枯萎死亡。其主要防治措施如下: First, the rotten roots in winter, by the low temperature, low ground temperature and lack of light, nursery bed humidity and other factors, often rotten roots in the nursery phenomenon, affecting the normal growth of seedlings. The general symptoms of the roots showed rust-colored rotten roots after the slow growth of the excavated, no new roots, and some even stopped growing, gray-green leaf color and gradually turn yellow, resulting in whole plant withered death. The main control measures are as follows: