索雷剑线虫（Xiphinema thornei）在梨园的发生及其对梨树的影响

天津市静海县双塘乡朴楼梨园土壤中含有Ｘｉｐｈｉｎｅｍａｔｈｏｒｎｅｉ，Ｃｒｉｃｏｎｅｍｏｉｄｅｓｓｐ，Ｈｅｌｉ－ｃｏｔｙｌｅｎｃｈｕｓｓｐ．和Ｓｃｕｔｅｌｌｏｎｅｍａｓｐ．４种主要寄生线虫，其中Ｘｉｐｈｉｎｅｍａｔｈｏｒｎｅｉ发生频率为７５％，平均密度为５３条／２００ｍｌ土壤，为优势种群，检查梨树根系发现根尖形成典型的极尖瘤，占所取样品总数的３６．５％，病情指数为１３．２。地上部观测发现枝条稀疏。

Occurrence of Xiphinema thornei in pear orchards and its effect on growth vigor of plants

Four species of plant parasitic nematodes,Xinphinema thoruei,Criconemoides sp,Helicoty-lenchus SP.and Scutellonema SP.were isolated from soil in an experimental pear orchard.X.thornei appeared most prominent in population,with frequency being 75%and 53 heads in 200ml soil.The infected plant formed galls on root tips with disease index being 13.2,it was true for36.5%of samplings. The vrowth vigor of infected plants seriously declined,shoots sparsed and fruitnumber decreased.On the body of X.thornei isolated from soil were parasited a lot of individualsof some fungi,with parasiting frequency being of 27.9%.The results demonstrated that one im-portant reason causing the plant growth vigor of all the orchard to be declined year by year mightbe the X.thornei,and the soil parasiting fungus was the key biological factor which inhibited thepopulation of X.thornei.