Evidence of Hemlock woolly adelgids on hemlock tree needles are seen in Massachusets in 2016. No larger than a speck of pepper, the Hemlock woolly adelgid spends its life on the underside of needles sucking sap and eventually killing the tree. The aphid-like bug is part of an expanding army of insects draining the life out of forests from New England to the West Coast. Elise Amendola/AP