The emerald ash borer (Agrilus planipennis) is an invasive, wood-boring beetle. The adult beetles nibble on ash foliage but cause little damage. The larvae (the immature stage) feed on the inner bark of ash trees, disrupting the tree's ability to transport water and nutrients.
The emerald ash borer (EAB) probably arrived in the United States on solid wood packing material originating in its native Asia. Since its discovery in 2002 in Michigan, the EAB has killed hundreds of millions of ash trees from Colorado and the Midwest to New England and south to Georgia. It has caused regulatory agencies and the USDA to enforce quarantines to prevent potentially infested ash trees or wood from spreading EAB, and it has cost municipalities, property owners, nursery operators and forest products industries hundreds of millions of dollars.