危害症状 子叶受害时,大多在边缘出现褐色圆形或半圆形病斑,上边有黑色及淡红色粘稠物。叶片发病,最先呈现淡黄色水浸状圆形斑点,很快变成黑色或紫黑色圆斑,外围有一紫黑色晕圈,也有些有同心轮纹出现;潮湿时,叶片正面病斑出现粉红色小点,以后变成黑色;干燥时病斑破碎,严重时病斑汇合成大斑块而使叶片枯死。瓜蔓和叶柄发病、出现稍微凹陷的圆形或纺锤形黑色病斑,逐渐环绕蔓和叶叶柄一周,切断养分和水分的通 Harmful symptoms cotyledons victims, mostly in the edge of the brown round or semicircular lesions, above the black and light red sticky. Leaves the incidence of the first to show a light yellow flooding-like circular spots quickly become black or purple black spot, the outer periphery of a purple black halo, and some concentric lines appear; moist, the front of the leaves appear pink Small dots, later into a black; dry lesion broken, severe plaque merged into large patches and leaves withered. Melon and petiole incidence, a slight depression of the round or spindle black lesions gradually around the vine and leaf petiole week, cut off nutrients and water through