1症状识别初发时，叶片产生小黑点，逐渐扩大成圆形或近圆形、暗褐色或灰褐色病斑，有不明显的轮纹，病斑周围有时具黄色晕圈，湿度大时病斑中央两面都产生黑色霉层，即病菌的分生孢子梗和分生孢子。严重时，病斑布满叶片或汇合成不规则形大斑，霉层密织呈墨绿色，致叶片变黄枯 1 Symptoms Identification of the first issue, the leaves produce small black spots, and gradually expanded into a round or nearly circular, dark brown or taupe spots, there is no obvious round pattern, sometimes with a yellow halo around the lesion, humidity Both sides of the lesion have black mold layer, namely, germ conidiophores and conidia. In severe cases, the patches covered with leaves or confluence into irregular shaped big spot, mildew dense dark green, causing the leaves turn yellowish-brown