Hemlock woolly adelgid (Adelges tsugae), commonly abbreviated as HWA, is a true bug native to East Asia

East Asia

East Asia or Eastern Asia is a subregion of Asia that can be defined in either geographical or cultural terms...

 that feeds by sucking sap from hemlock trees (Tsuga

Tsuga

Tsuga is a genus of conifers in the family Pinaceae. The common name hemlock is derived from a perceived similarity in the smell of its crushed foliage to that of the unrelated plant poison hemlock....

spp.). In eastern North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

, it is a destructive pest that poses a major threat to the eastern hemlock (Tsuga canadensis) and the Carolina hemlock (Tsuga caroliniana). The range of Eastern Hemlock extends north of the current range of the adelgid, but there are fears that the adelgid could spread to infect to these northern areas too.