New Hampshire Department of Forest and Lands

hemlock trees

Hemlock Woolly Adelgid & Elongate Hemlock Scale

healthy hemlock branch     diseased hemlock branch

Hemlock Woolly Adelgid is a small wingless insect which has piercing mouthparts to feed in the xylem of the small hemlock twigs. This insect is originally from Asia and was first discovered in Portsmouth in 2000. Elongate Hemlock Scale is an exotic scale insect that prefers hemlock, spruce and fir but will also feed on cedar, pine, and yew. This insect was introduce to New York in 1908 from Japan and has since spread north to Maine and south to North Carolina. Scale can also be found on trees infested with adelgid. Scale populations build slowly on healthy trees but more quickly on trees stressed by adelgid, drought, or other factors. Left untreated these pests can kill trees in NH within 10 years.


HWA Quarantine Eliminated

Managing Hemlock in Northern New England Forests


Check Out this great Documentary 



Please follow the following links to see a current maps of HWA and EHS in NH, the quarantine on hemlock material, and other related information.


Elongate Hemlock Scale Factsheet

Hemlock Woolly Adelgid Factsheet

Hemlock Woolly Adelgid Action Plan

UNH Cooperative Extension HWA webpage

UNH Cooperative Extension EHS webpage

Map of Towns with EHS Detections

Map of Towns with HWA Detections

Recent EHS Survey Map

Recent HWA Survey Map


Other factors affecting hemlock decline in NH:


Sirococcus tsugae Tip Blight

NH Department of Natural and Cultural Resources and the NH Division of Forests and Lands | 172 Pembroke Road, Concord, NH 03301