| return migration of helicoverpa armigera (lepidoptera: noctuidae) during autumn in northern china. | the autumn migration of helicoverpa armigera (hübner) was observed with radar and two types of light-trap at langfang, hebei province, china in 2001 and 2002. the sudden increase in the proportion of h. armigera moths in the searchlight trap indicated migration into the area and catches increased 10-fold during the second half of the night due to the landing of migrants before dawn. the moths' migratory flights took place at up to 2000 m above the ground, and moths flew differentially at times, ... | 2005 | 16048684 |