马铃薯晚疫病植株各部位都可发生。在叶片上,先在叶尖或叶片边缘发生淡褐色小斑点,气候潮湿时,病斑扩大成褐色,病叶成水浸状而坏死,病斑外围有一圈淡绿色组织,上有 Potato late blight can occur in all parts of the plant. On the leaves, light brown spots first appear at the tip or the edge of the leaves. When the climate is wet, the lesion expands to brown, the diseased leaves become flooded and necrosis, and the periphery of the lesion has a light greenish tissue with