牡丹各生长期各生长部位均可受侵染灰霉病。幼苗期爱害,茎基初吐暗绿色、水渍状不定形病斑,后变褐色,病部凹陷、腐烂,严重时幼苗倒伏,叶片和叶柄被侵染后,病斑呈圆形褐色并有不规则状的轮纹。病斑多发生在叶尖和叶缘处,感病的花芽通常变黑或花瓣枯萎。在盛花期,花被侵染后则变成褐色腐烂。茎部被危害时,常引起病部腐烂并使茎、枝折断。病茎上可见到环形、表面光滑、黑色的菌核。遇潮湿天气,发病部位均产生灰褐色霉层。 All growth parts of peony can be affected by gray mold disease. Seedling damage, dark green stem early initiation, water stain like shaped lesion, after turning brown, diseased dent, decay, severe seedling lodging, leaves and petioles were infected, the lesions were brown and brown Irregular wheel pattern. Lesions often occur at the tip and leaf margin, and the diseased flower buds often become black or the petals wilt. In full flowering period, perianth becomes brown decay after infection. When the stem is endangered, it often causes the rot of the diseased part and makes the stem and branch broken. Sick stem can be seen ring, smooth surface, black sclerotia. In case of wet weather, the incidence of parts have gray-brown moldy layer.