一、发病症状幼苗刚出土或移苗后,倒向地面,而子叶和幼嫩真叶不凋萎,以后子叶和真叶青枯,幼苗死亡。发病后,易向四周蔓延扩展。严重时,幼苗成片猝倒死亡。有时,幼苗出土前子叶和胚轴已腐烂。二、诊断要点病苗近地面茎部呈水烫状,发黄、变软缢缩,湿度大时,发病部位或病株附近长出白棉絮状菌丝。 First, the symptoms of seedlings just unearthed or transplanted seedlings, fell to the ground, and the cotyledons and young true leaves do not wither, after the cotyledons and true leaf green dead seedlings died. After the onset, easy to spread around the expansion. In severe cases, the seedlings die suddenly die down. Sometimes, cotyledons and hypocotyls have decayed before seedlings are excavated. Second, the diagnostic points Stems near the ground water was hot, yellow, soft constriction, humidity, the incidence of diseased sites or diseased plants grow white flocculent cotton floss.