在加拿大曼尼托巴,由真菌Peronospora ducometi引起的荞麦霜霉病的症状曾于1978年作过报导,自那时以来,几乎只在叶片上才看到过此症状。褪色的局部病斑,平均直径为20毫米,局限性病斑结合在一起就形成了大型不规则的褪色区,这些区和斑纹常常扩大到叶片的绝大部分。叶部受害区的颜色一般为浅绿色,有些圆形局部病斑出现坏死。其他国家关于 The symptoms of buckwheat downy mildew caused by the fungus Peronospora ducometi in Manitoba, Canada, were reported in 1978 and since then the symptoms have only been seen on leaves. Faded local lesion with an average diameter of 20 mm, localized lesions combine to form large irregular discolouration zones that often extend to most of the leaves. Leaf color of the victim area is generally light green, and some circular necrosis of the local lesion. Other countries about