A seven-year field study that included UMass Amherst researchers Roy van Driesche and Kris Abell, found that a tiny wasp, Tetrastichus planipennisi, contributed to a significant reduction in emerald ash borer population growth in central Michigan. The U.S. Forest Service estimates the response to the emerald ash borer could cost up to $10.7 billion between 2009 and 2019. Environmentguru.com