The major forest insect pests in Alberta include defoliators (eastern spruce budworm, forest tent caterpillar) and bark beetles (mountain pine beetle and spruce beetle). Defoliators are bugs that eat the leaves off of trees and plants. The major forest diseases are dwarf mistletoe, wood decay, armillaria root rot and stem cankers.
Insect pests and disease represent a major disturbance of forests ecosystems in Alberta. From 1988-1992, the estimated average yearly growth loss due to major forest insect pests and diseases in Alberta was the equivalent of about one-half of the timber volume harvested in the province during the same period.
