NHBugs

Protecting trees and forests

Hemlock Woolly Adelgid

Tip blight on eastern hemlocks

A disease on natural regeneration. May be mistaken for HWA.

Hemlock Woolly Adelgid (HWA), originally from Asia, was first discovered in New Hampshire in Portsmouth in 2000. This small, wingless insect uses its piercing mouth-parts to feed on small hemlock twigs. HWA, left untreated, can kill a tree in 4 to 10 years. Today there are many communities throughout the southeast and lakes region with small infestations. In an effort to slow the spread of this pest, the N.H. Division of Forests and Lands developed an action plan, which includes a quarantine on hemlock material from all infected NH counties.

Untreated outbreaks of HWA weaken the tree and leave it susceptible to damage from other pests, such as elongate hemlock scale and hemlock borer. Maintaining trees in a healthy condition lessens damage by other pests.

The Basics and What to Do

HWA and Other Exotic Insects

Important HWA Websites

Towns with Infestations

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Treatment status (includes elongate hemlock scale)

HWA treatment status

 

 

 

 

Harvard Forest's ecologist, David Orwig, discusses threats to our native forests.