Abstract: The damage of sweet potato tissues and cells caused by D.destructor has been observed by SEM,as compared with the healthy sweet potato.The study results indicate that many pathological changes occur in diseased sweet potato tubers.In the tubers with slight or medium infection,the cells shrink with larger gaps due to the loss of water.The starch grains become smaller and distorted,and some nematodes can be found.The severely infected tubers,the cells shrink severely with larger gaps due to the loss of water,while the vascular tissues are distorted or even brocken.In this case,the starch grains obviously decrease in number,or even disappear,with decreased number of nematodes.This study has confirmed the parasitic and migratory in vivo characteristics of nematodes.

Key words: Stem nematode, Ditylenchus destructor, Sweet potato, Pathomorphology

CLC Number: 

• S435.31