Abstract: Investigations on the spatial construction and distribution of Myzus persicae and Erigonidium graminicola in a plum orchard were conducted from March 2003 to November 2003.The results indicated that the semivariogram of Myzus persicae could be described by spherical model,except on June 27 and November 22,which should be described by lined model,and that of Erigonidium graminicola could be described by spherical model,except on May 21,May 31,October 19 and November 22,which should be described by lined model.It could be concluded that the amount and spatial distribution of Erigonidium graminicola was closely related to those of Myzus persicae.

Key words: Life history, Disturbance, Seed morphology, Vegetative reproduction, Soil seed bank