Help Track a Hemlock Pest : National Invasive Species Awareness Week

Help Track a Hemlock Pest : National Invasive Species Awareness Week

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Invasive Species Awareness & Action

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Help Track a Hemlock Pest

Hemlock woolly adelgid is on the move in Maine. Help us track its spread.

a hemlock twig with hemlock woolly adelgid wool

Image: Hemlock woolly adelgid (HWA) is visible on the underside of hemlock twigs in the winter. Photo: Maine DACF

Hemlock woolly adelgid (HWA) is an aphid-like invasive insect that feeds on and can kill hemlock trees in Maine. To find HWA, look:

  • On hemlock trees. In North America, HWA is found only on hemlock trees.
  • On the undersides of hemlock twigs. At this time of year, HWA is covered in white tufts of wax and is easy to see. Look for discrete ‘woolly’ masses.
  • At fallen twigs on top of the snow, as this will give you a picture of what is happening high in the crown.

Unless you are in an area where HWA is commonly found (such as southern coastal towns), please let us know if you find it

Map of Maine showing towns with hemlock woolly adelgid- 2025

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