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HWA Survey #1

The first of our winter Hemlock Woolly Adelgid surveys took place yesterday (1/19/2024) at our Dobbins Woods Preserve in Ashville, with members of our staff and conservation committee and our two SUNY JCC interns looking for signs of infestations of this invasive insect during its dormant period. We are happy to report that no signs of HWA were found at the preserve!

The group also traveled to Lakewood to check on a number of trees that had a reported infestation a couple of years ago and that had been treated for it. As of yesterday, those trees showed no signs of HWA activity, meaning the treatments are so far working! On a not-so-happy note, some trees on adjacent properties now have an infestation. These infestations appear to be localized to just a few neighbors, though, so if those trees can be treated now, many or all of those hemlocks can be spared.

HWA is an invasive, aphid-like insect that attacks North American hemlocks. They are very small and often hard to see, but they are easily identified by the white, cotton-like “woolly” masses they form on the underside of branches at the base of the tree’s needles. HWA feed on a hemlock’s stored starches, which disrupts the flow of nutrients to the tree’s twigs and needles. The health of the tree then declines, and without intervention or treatment, the tree will eventually die, usually within 4 to 10 years. If you see a hemlock tree with an infestation, please report it to us or to WNY PRISM (

photos by Janis Alm Bowman and Bethany O'Hagan

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