Abstract:The acetylcholinesterase (AChE) properties of four populations of Ditylenchus destructor and susceptibilities to inhibitors were investigated. AChE was extracted in a direct method and ultracentrifugetion in sucrose gradients. AChE activities were determined by the amended spectrophotometric method of Ellman. Effect of inhibitors on AChE hydrolysis was analyzed. The results showed that there are two major class AChEs in acetylcholine hydrolysis at least. One class of AChE is highly sensitive to eserine (IC50<10-6mol/L) and other class is less sensitive to eserine (IC50>10-4mol/L). Inhibition of AChE activity of Changli population was higher than that of Zhuozhou, Lulong and Funing populations at the concentration 10-6-10-10mol/L of eserine and at 10-5-10-10mol/L of aldicarb. This susceptibilities difference of AChE of different populations to inhibitors may be due to the polymorphism of AChE and the multiple changes of different molecular polymorphism.