Why isn't hemlock woolly adelgid (Adelges tsugae) a pest in western North America?

Sunday, November 16, 2014: 9:12 AM
E145 (Oregon Convention Center)
Aaron S. Weed , Dept. of Environmental Conservation, University of Massachusetts, Amherst, MA
Joseph Elkinton , Dept. of Environmental Conservation, University of Massachusetts, Amherst, MA