河南省中牟县种植西瓜历史悠久,常年种植面积1万hm2左右。近年来,随着西瓜保护地栽培技术模式的大面积推广应用,在西瓜生产上出现一种本地过去未见的病害。发病早,为害重,损失大。在温室育苗期和大棚、小拱棚内种植,发病率一般为10%～25%,高者达60%左右,减产20%～30%,已成为本? Zhongmou County, Henan Province, planting watermelons has a long history of perennial planting area of ​​about 10,000 hm2. In recent years, with the large-scale popularization and application of cultivation techniques for watermelon protected areas, a disease that has not been seen in the past has emerged in watermelon production. Early onset, serious damage, big loss. Planting in the greenhouse and greenhouse, small shed planted, the incidence rate is generally 10% to 25%, the highest of about 60%, cut 20% to 30%, has become the?