It now occurs throughout North America, wherever its host plants are grown. In Western Canada, canola and mustard are its primary targets. Although the diamondback moth occurs each year throughout the Canadian prairies and north central United States, the severity of the infestation varies considerably from year to year. The most recent widespread infestation occurred in 1995.
Crop damage is caused by the larval stage.
Normally, the diamondback moth takes about 32 days to develop from egg to adult. However, the time to complete a generation may vary from 21 to 51 days depending on weather and food conditions. There may be several generations per growing season. Generations usually overlap and all four life stages may be present in the field at the same time. At rest, the moth folds its wings over the abdomen in a tent-like manner.