Hemlock Woolly Adelgid: Biology and Management
Hemlock woolly adelgid (Adelges tsugae, HWA) is an aphid-like invasive pest of hemlock trees in eastern North America. The HWA is native to all hemlock species in western North America and Asia, and hemlock trees in these regions are unaffected by HWA infestations.1 However, hemlocks in the eastern United States have not adapted to this pest, and HWA has caused widespread decline and mortality in eastern and Carolina hemlocks in this region. The HWA was first detected in Richmond, Virginia in the early 1950s, and has since spread from southern Maine to Georgia, and as far west as Kentucky.2 The extensive loss of hemlock has severely impacted ecological and forest stand dynamics in eastern forests and is a public safety hazard in urban and suburban landscape settings.
Darr M, Coyle D, Burgess LW. Hemlock Woolly Adelgid: Biology and Management. Land-Grant Press by Clemson Extension. 2019; LGP 1020. http://lgpress.clemson.edu/publication/hemlock-woolly-adelgid-biology-and-management/.