Abstract: The meadow moth，Loxostege sticticalis L., is an important farming migratory pest in North China, and the understanding of the exact overwintering area and migratory path for the pest is essential for establishing a population forecasting system. In this study, we developed a long-term monitoring observation of the pest using a vertical-looking radar (VLR), checked up the ovarian develop ment and collected the number of meadow moths in light trap at different points during the peak migration period of meadow moth. We also analyzed the weather background during the major immigration period, especially, low altitude airflow and large-scale atomspheric circulation. Finally, we did numerical simulation on migration dynamics of meadow moth with Hysplit_4 (HYbrid Single Particle Lagrangian Integrated Trajectory). The results showed that meadow moths during June 7－9 showed a typical physiological characteristic of migrating insects and the moths usually took advantage of strong winds to fly and formed main migrating layers at 300-500 m above ground level (agl), mainly at 400 m (agl), and lasted 9 h in one night. Part of the meadow moth population in the northeast of China immigrated from Wumeng, Inner Mongolia, and part from the middle-east part of Mongolia and the border areas of China and Russia. It is so inferred that population intercourse of the meadow moth may exist between China and neighboring countries.

Key words: Loxostege sticticalis, migration, radar observation, airflow analysis, population source