Hemlock woolly adelgid

Hemlock woolly adelgid (Adelges tsugae), or HWA, is member of the Sternorrhyncha suborder of the Order Hemiptera and native to East Asia. It feeds by sucking sap from hemlock and spruce trees (Tsuga spp.; Picea spp.). In eastern North America, it is a destructive pest that gravely threatens the eastern hemlock (Tsuga canadensis) and the Carolina hemlock (Tsuga caroliniana). Though the range of eastern hemlock extends north of the current range of the adelgid, it could spread to infect these northern areas as well. Accidentally introduced to North America from Japan, HWA was first found in the eastern United States near Richmond, Virginia, in the early 1950s. The pest has now been established in eighteen eastern states from Georgia to Massachusetts, causing widespread mortality of hemlock trees. As of 2015, 90% of the geographic range of eastern hemlock in North America has been impacted by HWA.