倒苗又叫化苗,是冬暖大棚栽培瓜果类蔬菜育苗中发生比较普遍,影响生产较大的问题。一般幼苗出土到第一片真叶出现前后最易发病。最初,苗床中仅有少数苗子倒在地上,但至第二天就会突然成片死亡,损失很大。这主要是因感染猝倒病和立枯病所致,发病原因是:①在重茬地、旧苗床、旧床 Tiao Miao and called Miao Miao, is the winter greenhouse cultivation of melons and vegetables in the emergence of more common, affecting the production of larger problems. General seedlings unearthed to the first true leaf before and after the most prone to disease. Initially, only a few seedlings in the seedbed fell to the ground, but it suddenly died in the next day, with a big loss. This is mainly due to damping-off and damping-off caused by infection, the incidence of the disease are: ① in stubble field, old seedbed, old bed