Report hemlock woolly adelgids to ODNR

Mill Creek Park
Eastern hemlock branches stretch over the waterway at Mill Creek Park in Youngstown, Ohio. Sara Welch photo.

COLUMBUS — The Ohio Department of Natural Resources Division of Forestry is asking for the public’s help to keep invasive pests out of Ohio’s forests. ODNR is encouraging people to report sightings of hemlock woolly adelgids, insects that can threaten hemlock forests. 

HWA are tiny aphid-like insects that feed at the base of hemlock needles, depleting the trees’ stored energy. This causes tree decline and eventual death after several years. 

The insects can easily be identified by white “woolly” masses on the underside of branches and at the base of needles. They will only be found on the evergreen needles of eastern hemlock trees and will not be found on deciduous, broadleaf trees. HWA are most easily spotted from October through June. 

If you think you have found HWA, try to collect a sample, or take a quality photo, and then report it through one of the following options: online using EDDMapS; notify the Plant Pest Control Section of the Ohio Department of Agriculture via their Plant Pest Reporter tool, by phone at 614-728-6400, or by email at


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