根结线虫病是山药(Dioscorea quinquelobaThumb)的重要病害,山药受害后可减产2 4 %～4 0 % ,重者可达6 0 %～80 % ,甚至块茎完全不能食用。为此,笔者自1993年起对山药根结线虫病的发生情况进行了观察,并对发病因素进行了分析。1　调查方法1.1　症状、病原及发病情况观察　1993 Root-knot nematode disease is an important disease of yam (Dioscorea quinquelobaThumb), yam can be reduced by 24% ~ 40% after the victim, the weight of up to 60% to 80%, and even tubers can not eat. To this end, the author from 1993 on the incidence of root knot nematode disease were observed, and the incidence of factors were analyzed. 1 survey methods 1.1 symptoms, pathogens and incidence of observation 1993