炭疽病是山药最为普遍、危害最为严重的病害之一。该病菌既可侵染山药的藤茎,也可侵染山药的叶片。藤茎染病最初在茎基部产生梭形或不规则褐色病斑,并逐渐向上发展。环境对发病有利时,病斑逐步扩大并融合成片,导致山药整株枯死。叶部染病有急性型和慢性型两种,慢性型病斑较大,发病较慢;急性型发病快,危害重。发病初期多在叶柄与叶片(或叶柄与茎蔓)交界处出现不规则的褐色病斑,叶面病斑较 Anthrax is one of the most common and endangered diseases of yam. The bacteria can infect yam cane can also be infected yam leaves. Cane infection initially produces spindle-shaped or irregular brown lesions at the base of the stem and progressively increases. Environment beneficial to the disease, the lesion gradually expanded and integrated into pieces, resulting in the whole plant dead yam. Leaf disease with acute and chronic type two, chronic type larger lesion, the incidence is slower; acute onset, harm heavy. Occurred early in the petiole and leaves (or petiole and stems and vines) at the junction of irregular brown spot, leaf lesions than