The New York State Department of Environmental Conservation (DEC) and partners are reporting that they have completed this year’s treatment to control and prevent the spread of Hemlock Woolly Adelgid (HWA) on New York State “Forever Wild” Forest Preserve lands at Lake George in Washington County, as part of an ongoing, multi-year effort.
DEC confirmed the HWA infestation in August. The affected hemlock trees were located in the Glen Island Campground on the shore of Lake George, along the shoreline of Shelving Rock Special Management Area, at the Buck Mountain Trailhead, and on Dome Island.
After the initial finding of HWA, DEC, Cornell’s New York State Hemlock Initiative, the Adirondack Park Invasive Plant Program (APIPP), and Lake George Land Conservancy staff spent approximately 100 working days surveying and delineating the infestation to prepare for treatment, they said. Additional survey and treatment will be required in future years to effectively manage this infestation.
Treatment began Oct. 6, and was conducted over a three-week time period by DEC’s Division of Lands and Forests. DEC crews from across the state were supported by partners from Capital District/Mohawk Partnership for Regional Invasive Species Management and APIPP.
In total, 275 working days were spent during the treatment period covering 138 high priority acres. Within the 138 acres approximately 2,500 hemlock trees were treated to kill any present HWA and protect from any future infestations.
Trees were treated with both imidacloprid (long lasting) and dinotefuran (quick acting) pesticides and were primarily treated with a targeted basal bark spray application to limit any impacts to non-target species.
Additionally, 80 trees in sensitive locations were treated by a direct injection method to further reduce impacts on non-target species and to the watershed. As part of a biological control effort to combat HWA within the infestation area, DEC partners at the New York State Hemlock Initiative released 620 Laricobius beetles, which feed on adelgids.
Early detection and rapid response to invasive pests is now central to protecting New York’s natural resources.
Signs of HWA on hemlock trees include 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) by visiting DEC’s website.
- Report the infestation 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.
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 insects 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 provide critical habitat for many of New York’s freshwater fish, including native brook trout.
More information on HWA, including identification, control techniques, and reporting possible infestations can be found at Cornell’s New York State Hemlock Initiative webpage or call DEC’s toll-free Forest Pest Information Line at 1-866-640-0652 to report possible infestations.
Photo of Hemlock Woolly Adelgid provided by DEC.