山楂叶点病,又叫山楂叶斑病。主要为害叶片。发病时先在叶片侧脉间形成褐色针尖大的斑点,后逐渐扩大为直径2—4毫米的圆斑,颜色中部黄褐色,周缘色深。8月中下旬,病斑转为银白色,其上散生黑色小点粒。病斑聚成大片以后,叶片变黄脱落。此病为真菌性病害。主要以分生孢子囊在病叶上越冬。次年春季花期,散生分生孢子侵染叶片,6月间病叶增多,直至7、8月间仍有发生。 Hawthorn leaves disease, also known as hawthorn leaf spot. The main damage leaves. When the disease first in the lateral veins of the leaves to form a large brown tip of the spot, and then gradually expanded to 2-4 mm in diameter round, yellow central color, peripheral color depth. In mid to late August, the lesion turned silver white, scattered black dots on it. Lesions gather into large films, the leaves turn yellow off. The disease is a fungal disease. The main conidia in the diseased leaves wintering. The following spring flowering, scattered conidia invaded leaves, sick leaves increased in June, until July and August still occur.