• Mattson, William J.
  U.S.D.A. Forest Service
  
• Simmons, Gary A.
  Michigan State University
  
• Witter, John A.
  University of Michigan
  

The spruce budworm, Choristoneura fumiferana (Clemens), (Lepidoptera: Tortricidae) was first described from specimens collected in Virginia, but this native insect occurs primarily in the northern boreal forest from Newfoundland west to the McKenzie River near 66°N. The most extensive and destructive outbreaks have occurred in the maritime provinces (New Brunswick, Nova Scotia, Newfoundland), Quebec, Ontario, Maine, and the Great Lakes states. This defoliator feeds primarily on the new growth of balsam fir (Abies balsamea), red spruce (Picea rubens), white spruce (Picea glauca), and black spruce (Picea mariana). Sometimes it feeds on other conifers, such as eastern larch (Laris laricina), eastern hemlock (Tsuga canadensis), Engelmann spruce (Picea engelmannii), subalpine fir (Abies lasiocarpa), and eastern white pine (Pinus strobus).