洋葱是我区主要商品菜之一,种植面积大,产量高,经济效益显著。张掖市年播种面积约一万亩。一般亩产3000—4000公斤,高者达5000公斤以上。自1985年以来,由于霜霉病连年发生,致使洋葱产量下降,品质降低。一、危害程度: 据1987年在廿里堡、梁家墩、党寨、碱滩等乡集中产区调查危害严重。全市发病面积10000亩以上,占洋葱种植面积的71.4％。一般田块发病率50—70％,严重的100％。梁 Onion is one of the main commercial products in our district, planting area, high yield, significant economic benefits. Zhangye City sown area of ​​about 10,000 mu. General mu produce 3000-4000 kilograms, the highest of more than 5000 kilograms. Since 1985, downy mildew has occurred year after year, resulting in reduced onion production and lower quality. First, the degree of harm: According to 1987 in Baili Fort, Liangjiadun, Party Village, alkaline beach and other townships concentrated production survey serious harm. The city’s incidence of more than 10,000 acres, accounting for 71.4% of the area planted onions. The general field incidence of 50-70%, a serious 100%. Beam