Abstract: The spatial structure and spatial correlativity of both Macrosiphum granarium and Aphidius populations at different period were investigated with the method of geostatistics.The results showed that the semivariogram of M.granarium appeared as spherical type,indicating its spatial pattern was an aggregated type with a range from 33 to 57 cm.The semivariogram of Aphidius was fitted into spherical model too,indicating an aggregated spatial arrangement with a range of 36～55 cm.The amount and spatial distribution of Aphidius was closely related to that of M.granarium,suggesting that Aphidius is the dominant natural enemy influencing M.granarium population.

Key words: Macrosiphum granarium, Aphidius, Spatial pattern, Geostatistics