本文介绍的禾谷类作物霜霉病是指由指疫霉[Sclerophthoramacrospora(sacc)Thirum et al]引起的水稻、小麦、大麦和玉米几种主要禾谷类作物霜霉病(又称黄化萎缩病)。这种病害在我国发生历史悠久,分布亦广,许多省份都有发生。田间发病率一般在10%左右,重病田可达50%以上(表1)。由于这种病害是系统性的,病株多,且不结 The term “downy mildew” in this paper refers to the downy mildew (also known as yellowing atrophy) in several major cereal crops of rice, wheat, barley and corn caused by Sclerophthora macrospora (sacc) Thirum et al. . This disease occurred in our country has a long history, distribution is also wide, many provinces have occurred. Field incidence is generally about 10%, severe disease up to 50% or more (Table 1). As the disease is systemic, many strains, and not knot