 Considered the most destructive defoliator in British Columbia, sustained outbreaks of the western spruce budworm resulted in defoliation of over in the Fraser Canyon - Lillooet - Pemberton area from 1949-58.From 1970 -2001 further outbreaks occurred over a much larger area including the area of the previous outbreaks, as well as the Thompson and South Okanagan areas in 1970-2001.There is no typical pattern for western spruce budworm epidemics.