Abstract: The meadow moth, Loxostege sticticalis L. is an important migratory pest in North China, but its exact overwintering area and migratory path are still not clear. We analyzed the weather background during the major immigration period in 1999, and stimulated temporal-spatial dynamics of wind field and migration trajectories of the meadow moth. The results indicated that only little part of meadow moth population in the northeast of China in 1999 immigrated from “the main occurrence source area" as that people considered before, most of t he population should immigrate from the east part of Mongolia and bordering areas of China and Mongolia. The results also showed that cyclone system had notable effect on migration of the meadow moth. So the appearance and enhancement of low pressure or vortex could be a pre-warning indicator for the immigration of outbreak populations of the me adow moth in the northeast of China.

Key words: Loxostege sticticalis, outbreak population, migration, trajectory analysis