马铃薯晚疫病是一种侵染性、速发性、毁灭性病害,各大生产区均有发生,马铃薯晚疫病主要为害叶、茎和块茎,发病后叶部病斑面积和数量增长迅速,使全田马铃薯早期成片死亡,并引起块茎腐烂,严重影响产量。近几年有逐年加重的趋势,如防治不及时,一般可减产20%～30%,严重的可减产50%。为害症状:叶上病斑灰褐色,边缘不整齐,周围有一褪绿圈。在潮湿条件 The late blight of potato is an infective, rapid onset and devastating disease, occurring in all major producing areas. The late blight of potato is the major damage to the leaves, stems and tubers. After the onset of the disease, the area and number of the diseased leaves are rapidly increasing. The whole field of potato died early tablets, and cause tuber rot, seriously affecting the yield. In recent years, there is a trend of increasing year by year. If the prevention and treatment are not implemented in time, it can generally reduce the output by 20% to 30% and seriously reduce the output by 50%. Harmful symptoms: leaf brown spots, irregular edges, surrounded by a green circle. In wet conditions