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For Release: Thursday, September 10, 2020

DEC and Partners Announce Effort To Prevent Spread of Hemlock Woolly Adelgid

Ongoing Surveys Determine Extent of Infestation and Inform Control and Management of Invasive Pest

The New York State Department of Environmental Conservation (DEC) today announced that DEC and partners, including Cornell University's NYS Hemlock Initiative, the Adirondack Park Invasive Plant Program, and Lake George Land Conservancy, and The Fund for Lake George are developing a treatment plan to control and prevent the spread of Hemlock Woolly Adelgid (HWA) on Forest Preserve lands in the towns of Dresden and Fort Ann, Washington County. DEC confirmed the HWA infestation in August. The affected hemlock trees were located in the Glen Island Campground on the shore of Lake George. This is the second known infestation of HWA in the Adirondacks.

The most effective treatment for HWA control is the use of insecticides. The treatment includes a basal bark application of the pesticides, involving spraying the pesticides at the base of the tree. Consistent with best management practices, treatments will consist of applications of dinotefuran, a fast-acting insecticide that will quickly knock back HWA populations, and imidacloprid to provide long-lasting protection to hemlock trees in the area and prevent the spread of HWA to un-infested trees. DEC and partners are planning treatments to start this fall before HWA has the opportunity to spread next spring. In addition, DEC and Cornell are evaluating the use of biological controls to supplement these treatments.

After the initial finding of HWA, DEC, Cornell's NYS Hemlock Initiative, the Adirondack Park Invasive Plant Program, and Lake George Land Conservancy staff conducted follow up surveys at neighboring campsites on nearby islands and along 16.3 miles of shoreline to determine the extent of the infestation. The partners identified a HWA infestation on nearly 250 acres along 1.5 miles of shoreline on the eastern shore of Lake George. Surveyors have spent more than 500 hours surveying to date. Surveys will continue at priority locations to determine the extent of the infestation and find any additional infestations.

Most of the infested trees have a low density of HWA, with the densest HWA infestations located along the shoreline. This initial data suggests the infestation started along the shoreline-perhaps by migrating birds-and expanded from there.

Early detection and rapid response to invasive pests is critical to protect New York's natural resources. DEC and its partners' effort to further prevent the spread of HWA is critical to protecting the hemlock forests in the Lake George watershed.

Signs of HWA on hemlock trees includes white woolly masses (ovisacs) about one-quarter the size of a cotton swab on the underside of branches at the base of needles, gray-tinted foliage, and needle loss. DEC is asking the public to report signs of HWA:

  • Take pictures of the infestation signs as described above (include something for scale such as a coin);
  • Note the location (intersecting roads, landmarks, or GPS coordinates);
  • Contact DEC or the local Partnership for Regional Invasive Species Management (PRISM);
  • Report the infestation (leaves DEC's website) to iMapInvasives; and
  • Slow the spread of HWA by cleaning equipment or gear after it has been near an infestation and by leaving infested material where it was found.

About Hemlock Woolly Adelgid
HWA, a tiny insect from East Asia first discovered in New York in 1985, attacks forest and ornamental hemlock trees. It feeds on young twigs, causing needles to dry out and drop prematurely and cause branch dieback. Hemlock decline and mortality typically occur within four to 10 years of infestation in the insect's northern range. Damage from the insect has led to widespread hemlock mortality throughout the Appalachian Mountains and the southern Catskill Mountains with considerable ecological damage, as well as economic and aesthetic losses. HWA infestations can be most noticeably detected by the small, white, woolly masses produced by the insects that are attached to the underside of the twig, near the base of the needles.

Eastern hemlock trees, which comprise approximately 10 percent of the Adirondack forest, are among the oldest trees in New York with some reaching ages of more than 700 years. These trees typically occupy steep, shaded, north-facing slopes and stream banks where few other trees are successful. The trees help maintain erosion control and water quality, and the hemlock's shade cool waters providing critical habitat for many of New York's freshwater fish, including native brook trout.

To support New York State's overall effort to combat invasive species, the 2019 State Budget included a total of $13.3 million in the Environmental Protection Fund targeted specifically to prevent and control invasive species. This funding is providing critical support for prevention, eradication, research, and biological control efforts through programs like the New York State Hemlock Initiative and Partnerships for Regional Invasive Species Management (PRISM) that protect against threats to New York's biodiversity, economy, and human health.

More information on HWA, including identification, control techniques, and reporting possible infestations can be found at Cornell's New York State Hemlock Initiative or call DEC's toll-free Forest Pest Information Line at 1-866-640-0652 to report possible infestations.

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