莲藕链格孢叶斑病,又称黑斑病、叶斑病、褐纹病,是莲藕的一种主要病害(图1)。各地均有分布。病株率30%~60%,发病程度较轻,对生产无明显影响;重病田发病率可达80%以上,明显影响莲藕产量和质量。该病主要侵害叶片。发病初期,叶片上出现针头大小黄褐色小斑点,以后扩大成近圆形或不规则形轮纹状病斑,直径一般0.6~1.5厘米,褪绿大黄斑或褐色枯死斑,背面较正面明显,病斑边 Alternaria Alternaria leaf spot disease, also known as black spot disease, leaf spot disease, brown-spot disease, is a major disease of lotus root (Figure 1). All parts are distributed. Disease rate of 30% to 60%, the lesser degree of light, no significant impact on production; severe disease incidence up to 80% or more, significantly affecting lotus root yield and quality. The disease mainly affects leaves. Early onset, the needle appears on the size of the small yellowish brown spots, and later expanded into nearly round or irregular round-shaped lesions, diameter of 0.6 to 1.5 cm, chlorotic macular or brown dead spot, the back is more obvious than the front, Sick side