A knowledge of dispersal is essential to an understanding of population control and to the management of insecticide resistance. The Division of Entomology, CSIRO, is undertaking ecological studies and radar observations to quantify dispersal of Heliothis moths at a range of.altitudes over crops. We are interested both in assessing the value of radar in following low-level movement, and in determining the type of population data that need to be collected to interpret observations made by the radar. A preliminary study in the Darling Downs during February 1984 included direct observations of the frequency, magnitude and direction of movement, and indirect assessments of such movements using various types of trapping.