病名主要症状防治方法初期叶面出现褐色小点后扩大为病斑遍布叶片。湿度大时可见病叶背面有一层灰白色的霜霉状物 ,最后全叶烂去或干枯。①多雨季节疏沟排水 ,防积水为害。②可与禾木科作物轮作几年③发病初期喷洒４０ %霜疫灵２５０倍液或是５０ %瑞毒霉５００倍液 ,一星期一 The main symptoms of disease Prevention and treatment methods The initial emergence of small brown spots on the leaves expanded to lesions around the leaves. Humidity is visible when there is a layer of off-white creamy mildew on the back of the leaves, the last leaves rot or go dry. ① drainage season ditch drainage, anti-water damage. ② with crop rotation of Hemu Branch a few years ③ the early onset of spraying 40% of cream fry spirit 250 times 50% or 50% Rana mold, a week