每年的6、7月份,是山药炭疽病发病最严重的时期。山药炭疽病也称山药落叶病,是农民最感头痛的病害,在许多地方,由于没能掌握防治时机,几乎成为不治之症。山药炭疽病可侵染藤茎、叶。藤茎染病始于茎基部,初产生梭形或不定形褐色病斑,病斑逐渐向上发展,严重时病斑融合成片致整株枯死。叶部染病有急性型和慢性型两种症状类型,慢性型病斑较大,发病较慢,发病初从叶尖或 June and July each year, the most serious period of the incidence of anthrax yam. Yam anthrax, also known as yam deciduous disease, is the most troubling disease among farmers. In many places, it has almost become an incurable disease because of its failure to grasp the timing of prevention and treatment. Yam anthrax can invade cane, leaf. Cane infection began at the base of the stem, initially produced fusiform or amorphous brown lesions, lesion gradually upward development, severe lesions merge into pieces cause whole plant withered. Leaf disease with acute and chronic type of two types of symptoms, chronic type larger lesion, the onset is slow, early onset from the tip or