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Hemlock Woolly Adelgid in Central New York

Hemlock Woolly AdelgidThe hemlock woolly adelgid (Adelges tsugae), a small, aphidlike insect that threatens the health of eastern hemlocks (Tsuga canadensis) was detected for the first time in Tompkins, Seneca, Yates, and Schuyler Counties, New York, in 2008 and now appears to be spreading.

Heavy HWA infestation (above). Image credit: Mark Whitmore, Cornell Department of Natural Resources

Look for these signs of HWA infestation on your hemlocks:

  • White woolly masses at the base of needles on undersides of hemlock twigs
  • Off-color needles, often with a grayish cast
  • Premature needle drop and twig dieback

Light HWA infestation (below). Image credit: Mark Whitmore, Cornell Department of Natural Resources.

HWA Light Infestation

Hemlock Woolly Adelgid Resources

US Forest Service HWA Fact Sheet

General information about HWA from the Northeastern Area of the US Forest Service - includes impacts, control recommendations, and distribution maps.

Information from the NY Department of Environmental Conservation.



Don't be fooled by these Look-alikes - They are not hemlock woolly adelgid!

HWA Imposters

Many things look like hemlock woolly adelgid at first glance. On closer inspection, they can be ruled out either because of their texture, their location or another characteristic. Remember, HWA will usually be found on the undersides of twigs at the bases of needles and is coated with a waxy material. When in doubt, contact us.

For more information about what you can do about hemlock woolly adelgid in central New York, please contact Mark Whitmore, Department of Natural Resources, Cornell University or Jerry Carlson, Lands and Forests Division, NY Department of Environmental Conservation.

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