Abstract:In order to fully understand the regular pattern of the population dynamics of Lithocolletis ringoniella Matsumura in the apple production region of the Loess Plateau, the distribution pattern and the ecological niche index were determined and the clustering analysis was conducted to describe the dynamic change of L.ringoniella population. The results showed that the leaf insect spot caused by L.ringoniella was visible in June; the number of the insect increased in July, with the damage symptom severe in August; and the quantity of the population number was in surge in September and October. The relative abundance of the temporal sequence was in a strong rising trend since August. Population distribution in the crown was uniform in early July and aggregative after that. The spatial distribution among the vertical positions of the tree crown showed significant difference, population number following the order of lower>middle>upper parts, whereas distribution among horizontal directions had no significant difference. The general distribution within the crown appeared in cluster, with individuals attractive to each other. The ecological niche occupation of this pest in vertical and horizontal directions as well as in temporal sequences are 0.179, 0.371 and 0.594, respectively. The resource utilization rate in the lower part of the crown reached 53.73% and almost nothing utilized in the upper part, indicating a more horizontal expansion potential. Viewing from the four directions, the maximum utilization of resources was in the north and east, up to 27.90% and 21.66% respectively. The ecological niche overlap index of L.ringoniella with hawthorn spider mite in vertical and horizontal directions reached 92.65 and 64.95, respectively, in addition to temporal sequence to be 66.36, indicating that hawthorn spider mite is the most intense space-temporal competitor for the limited resources of apple‘s crown leaves. The dominance degree index of L.ringoniella in the young apple orchard in different intercropping patterns increased over time since August and largest increase happened in the middle of August. The highest dominance degree index was found in soybean-apple intercropping pattern and the lowest index with sweet potato-apple intercropping pattern. The index fluctuated in the orchard with weeds unwell-managed.