Small-scale dispersal of the European corn borer and its relevance for resistance management in Bt maize

The small‐scale dispersal of the European corn borer (ECB) was studied in a release–recapture experiment using reared dye‐marked adults. Thereby, six light trap cages were set up across two maize fields at 50‐m intervals. In total, 736 marked ECBs were released, of which 10.2% were recaptured together with 212 unmarked naturally occurring adults after a period of 48 h. All marked–released individuals left the release point, with a mean dispersal distance of 195 m. Eighty‐two per cent of the recaptured ECBs moved to the second maize field across a ditch and associated shrubs. The spatial and temporal patterns of incidence of naturally occurring ECBs in the traps were consistent with those of the marked moths and showed an inhomogeneous distribution. There was a highly significant relationship between male and female densities in the cages. No ECBs were caught during a period of adverse weather conditions. Dispersal distances may be influenced by plant size, weather conditions during the flight, pheromonal patterns in the field and the timing of the flight.