[Spatial pattern of Tetranychus urticae population in apple tree garden].

Spatial pattern of insect population is an important aspect of insect ecology. It reveals the spatial structure characteristics of populations, and provides a basis for relevant sampling techniques and data transformation. Tetranychus urticae Koch is a serious pest of apple tree. Its spatial pattern and time-series dynamics were analyzed by calculating four indices of aggregation, and parameters of Iwao model. The results showed that the spatial pattern of T. urticae in apple tree garden belonged to an aggregated distribution pattern. The aggregation intensity was the highest in upper and southern part of crown, and the lowest in its lower and inner part. The aggregation was due to the biological habits of T. urticae and environmental heterogeneity. No matter T. urticae was in the upper, middle, or lower crown of apple tree, its aggregation intensity was higher before first ten days of June, and then gradually decreased after the middle ten days of June.