Migration Monitoring and Route Analysis of the Oriental Armyworm Mythimna separata (Walker) in Northeast China

The oriental armyworm Mythimna separata (Walker) is a worldwide migratory pest that threatens food security in China. Previous studies have clarified the general migration regularity of M. separata in East Asia, but knowledge of migration routes over northeast China, especially in autumn as well as the impact by climate change in recent years, is still limited. From 2017 to 2020, we monitored the migration of M. separata in northeast China by searchlight traps and simulated moth trajectories by the HYSPLIT model. The M. separata moths had three main migration periods in northeast China, and there were obvious seasonal differences at different latitudes. The spring and summer migrants (late May to early-mid June and late July to early August) came from the southern Shandong Province and migrated to the north via Hebei/Shandong-Liaoning-Jilin-Heilongjiang. Moreover, more than half of the autumn trapped insects from late August to mid-late September migrated in the provinces where the sites are located, southward via Heilongjiang-Jilin-Liaoning. These results clarified the migration route of M. separata in northeast China and their relationship with the insect source in north China, thereby providing a theoretical basis for regional monitoring, early warning, and management of the pest.