油菜霜霉病,在各地发生都很普遍。初期在叶上有淡黄色病斑,后期叶背长出一层白霜状霉,严重时病斑变淡褐色枯死,在油菜盛花期花序受害肿大喜曲,不能结实,严重影响着油菜的产量。因此,我们必须采取措施进行防治。 Rapey mildew is common in many places. In the early stage, there was a yellowish lesion on the leaves, and the latter had a layer of frosty mildew on the leaves. In severe cases, the lesion turned pale brown and withered. At the flowering stage of the rape, inflorescence was swollen, which could not be strong and seriously affected the yield of the rape . Therefore, we must take measures to prevent and control it.