一、大棚韭菜干尖症状 １、植株发育不整齐，叶细而弱，外侧叶先发生尖枯，而后整叶枯死。 ２、叶尖白化枯萎，严重时幼叶枯萎，大棚中有臭叶，叶缘周围变白。有的叶片先端产生水浸状斑，以后变成黑褐色而枯死。 ３、烧叶。一种是白化型（中部成熟叶，叶尖白枯），另一种是黄化 First, the greenhouse leek tip symptoms 1, plant development is not neat, thin and weak leaves, lateral leaf withered first, and then the entire leaf dead. 2, withered albino leaves withered, serious when the young leaves withered, greenhouses in the leaves, the edge of the leaves turn white. Some leaves apex flooding-like spots, later became dark brown and died. 3, burning leaves. One is the albino type (central mature leaves, withered leaves withered), and the other is yellow