Abstract:The migratory behavior of Helicoverpa armigera (Hübner) is a key factor resulting in its regional outbreak in China, and the understanding for relationship between migratory activity of the pest and climate environment is essential for establishing a population forecasting system. The migratory behavior of the second generation moths of Helicoverpa armigera was observed with insect radar in July and August 2000 at Langfang, Hebei Province. Alongside, a vertical pointing searchlight trap and a conventional light-trap were simultaneously operated to sample insect populations from high altitude and from near ground level respectively. Ovarian development analysis on the moths captured indicated that H.armigera population from high altitude was comprised of predominantly young individuals, and showed a typical physiological characteristic of migrating insects. H.armigera moths were observed to take off at dusk (20∶00), a half hour after sunset, and population density reached peak period in 1 h. Then, the area density decreased gradually as the moths emigrated. The moths generally ascended to altitudes of up to 1 000 m above ground level (AGL) with directions spiral clockwise up to high altitude, and formed main migrating layers at 200-300 m AGL. In most cases, the moths displaced at speed of 35-45 km/h and lasted 7-8 h in one night with the migration distance of 250-450 km.