Abstract: The clover cutworm, Scotogramma trifolii Rottemberg is a partially outbreaking pest in farming and stockbreeding areas of northern China. In recent years the pest present uptrend harm to crops. In this paper we reported a long-term monitoring observation of the pest using a vertical-looking radar (VLR) incorporate ancillary equipment and the data analysis by GIS. The results showed that the average soil temperature at 20 cm beneath in the middle ten days of May was lower than the developmental threshold temperature (10.6℃) for eclosion of the hibernated chrysalis. Airflow analysis of the late ten days of May in 2005 showed that south and southwest winds were preponderant in these days, which provided favorable airflow for insect migration. Simultaneous radar observations indicated that the nocturnally migrating clover cutworm generally flew at altitudes of up to 1 000 m above ground level (agl), with high density concentrations at about 300-500 m (agl). They could flight throughout the night at 500 m (agl). The ovarian development of the migrating moths showed typical characteristics of migratory insects. Based on these findings, the factors related to outbreak of this pest in Baicheng of Jilin province were discussed.

Key words: Scotogramma trifolii, migration, radar observation, GIS, population analysis