“With the recent history of the Midwestern United States as our guide, it can be presumed that it will infest and kill nearly every untreated ash tree in this city.”

— Vince Aquino, CU-Boulder’s lead arborist, regarding the emerald ash borer, a foreign beetle attacking ash trees around the U.S. CU arborists working with state and federal officials have released thousands of stingless wasps to kill the borers and their eggs.