The presence of both migrant and resident populations present a significant challenge for effective pest management: The case of the western bean cutworm.

The Western bean cutworm (WBC), previously limited to the western United States, has recently expanded its range into the Great Lakes region and there is evidence that resident populations exist in Ontario. An examination of female calling behaviour under different biotic (age/mating status) and abiotic (temperature/humidity) conditions showed that, regardless of rearing conditions, sexual maturation did not occur for several days after emergence, indicating that WBC is a migratory species. Furthermore, the timing of trap catch in a wide scale trapping network of pheromone traps would suggest that is still a significant annual immigration of adults early in the season. We will discuss the complications of developing effective pest management strategies when both immigrant and resident populations are present in a region.