近年来，随着山药栽培面积的扩大，山药根结线虫病的发生蔓延逐渐加重，轻者减产 20％～ 30％，重者减产 70％以上，并且商品品质明显下降，严重制约着我县山药生产的进一步发展。 1发生情况 　　山药根结线虫病病株在田间呈分散或条块状分布。山药根结线虫病主要发生在地下块 In recent years, with the expansion of yam cultivation area, the incidence of root knot nematode disease in Yam gradually increased, the light cut 20% to 30%, heavy cut more than 70%, and the quality of goods decreased significantly, seriously restricting the yam Further development of production. 1 occurred Yam root knot nematode disease in the field were scattered or bar-like distribution. Yam root knot nematode disease occurs mainly in the underground block