[Geostatistic analysis on spatial patterns of Aphis gossypii and Erigonidium graminicola]

The spatial structure and spatial correlativity of Aphis gossypii and Erigonidium graminicola populations during different periods were investigated by geostatistic methods. The results showed that the semivariogram of A. gossypii appeared as spherical type, indicating its spatial pattern was an aggregated type with a range of 7.33-12.40 cm, while that of E. graminicola was also fitted into spherical model, indicating an aggregated spatial arrangement with a range of 6.47-20.88 cm. The amount and spatial distribution of E. graminicola were closely related to those of A. gossypii, suggesting that E. graminicola was the dominant natural enemy influencing A. gossypii population.