Emerald Ash Borer

Emerald ash borer (Agrilus planipennis).
Photographer: Leah Bauer/USDA FS Northern Research Station, Bugwood.org
The emerald ash borer (Agrilus planipennis) could be as devastating to ash trees in the U.S. as the chestnut blight was to American chestnut a century ago.

Emerald ash borers (Planipennis agrilus) bore paths just below the bark of ash trees (Fraxinus spp.)
Photographer: Flickr user heathzib
This half-inch long, Asian metallic green beetle is a relative newcomer to America. First found in 2002 in Michigan, the emerald ash borer spread among ash trees quickly, often hitching rides on infested firewood and nursery stock.

By 2009, it had reached twelve states including Virginia and Maryland, and two Canadian provinces, killing hundreds of millions of trees.

Once infested, an ash tree typically dies within two or three years1.