The emerald ashborer, which decimates ash tree populations.
The "emerald ashborer" is a small, metallic, green beetle introduced from Asia about a decade ago -- and its larva burrow through ash trees and destroy them. Tens of millions of trees have been killed since the beetle was first discovered in Michigan in 2002, and it's been found in Virginia and Maryland.
One of the fastest ways the beetle moves is through infested firewood, specifically, by campers hauling firewood from a contaminated forest to a new one. The U.S. Department of Agriculture is asking campers this weekend to buy kiln-dried firewood and buy it locally at their destination to help prevent further spread of the pests.