The emerald ash borer first appeared in the U.S. in 2002. Now in 15 states, with tens of millions of dead ash trees in its wake, the tiny menace has developed into a full-blown infestation. Originally from China, the winged beetle loves the trees from which it derives its name, and with few natural predators in the U.S., it has had a field day. But America is fighting back. In the summer of 2011, the USDA will release 150,000 stingless wasps (their larvae eat ash borer eggs) to combat the beetle. Godspeed, stingless wasps.