Damage to canola occurs sporadically in northern and southern Alberta. Overwintering Found throughout Alberta, alfalfa loopers may overwinter in the pupal stage. However, most of the Alberta population is blown in from the United States each year. Spring appearance Early summer moths are likely to be migrants from the United States. The moths appear all summer long because generations overlap.
Moths feed on flower nectar at dusk and fly during daylight hours.
There are two or three generations per year. Damage Assessment Damage description Alfalfa loopers are an occasional pest in Alberta. Larvae are present from mid June through September. Small larvae feed on leaf surfaces and medium-sized larvae eat ragged holes through leaves. Older larvae feed along leaf margins and may defoliate a large portion of the plant as well as clip flowers and seed pods.