葡萄白腐病,俗称烂穗病。是葡萄的一种重要病害。病害流行的年份,损失可达50%以上,而且严重影响品质。一、症状与诊断。葡萄白腐病主要危害穗轴和果实,发病初期,先从离地面较近的植株穗轴或小果梗上开始,出现淡褐色不规则的水渍状病斑,而后逐渐蔓延到果粒上。果粒发病后7-10天左右,病果由褐色变为深褐色,果实软腐,果皮下密生白色略突起的小点,以后病果逐渐干缩成僵果。果粒和果穗易脱落,枝蔓多在受损伤的部位发病,病斑初为淡红褐色水渍状,以后颜色变深,表面也密生略为突起的灰白色小点。后期病浸皮层与木质部分离、纵裂,纤维散乱如麻,病部两端变粗。严重时病蔓易折断,或引起病部以上枝叶枯死;叶片发病,先从叶缘开始产生黄褐色边缘水渍状的病斑,逐渐向叶片中部扩展,形成近圆形的淡褐色大病斑, Grape white rot disease, commonly known as pan ear disease. Is an important disease of grapes. Year of disease epidemic, the loss of up to 50% or more, but also seriously affect the quality. First, the symptoms and diagnosis. Grape white rot disease is the main damage cob and fruit, early onset, the first from the ground near the plant cob or small fruit stems began to appear irregular light brown stain-like spots, and then gradually spread to the fruit . About 7-10 days after the onset of fruit, the fruit changes from brown to dark brown, the fruit soft rot, white peel under the peel slightly protruding small dots, and later the fruit gradually shrink into a stiff fruit. Fruit and ear easy to fall off, the branches and more in the damaged parts of the disease, the lesion early pale red brown water-like, after the color becomes dark, the surface is also slightly greyish slightly protruding white spots. Late disease diarrhea and xylem separation, longitudinal cracking, fibrous disarray, such as hemp, thick at both ends of the disease department. In severe cases, the disease is easy to break, or causes the branches and leaves to die more than the diseased parts. The leaves begin to develop yellow-brown edge water stains from the leaf margin and gradually expand to the middle of the leaf to form a nearly circular light brown big spot ,