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For Release: Thursday, October 19, 2017

DEC to Treat Schenectady County Preserve for Hemlock Pest

The New York State Department of Environmental Conservation (DEC) announced today that DEC and the Schenectady County Environmental Advisory Council's (SCEAC) Invasive Species Committee will begin pesticide treatments next week at the Plotter Kill preserve to combat the spread of the invasive pest hemlock woolly adelgid (HWA).

HWA is a non-native tree pest that can pose significant harm to the forest ecosystem and has recently been discovered at both the Plotter Kill preserve in the town of Rotterdam and the Indian Kill preserve in the town of Glenville.

Weather permitting, certified pesticide applicators will begin treatments in the Plotter Kill preserve the week of Oct. 23, and the preserve will be closed from Oct. 23 through 25. Signs will be posted at preserve parking lots and public access will be restricted during that time. In the event of rainfall during the application period, the application will be postponed to Nov.1 through 3.

The recommended treatment for HWA is the use of systemic insecticides applied to the base of the tree trunk and move to the tree canopy where the HWA feed. The two chemicals most commonly used for HWA management, imidacloprid and dinotefuran, have not been shown to have adverse health or environmental impacts at exposures that will occur with this treatment program.

DEC developed a HWA management plan for the Plotter Kill preserve, which was approved by SCEAC's Invasive Species Committee in September.

Hemlocks are an important part of natural ecosystems where they grow along streams and steep slopes and help to provide erosion control along streambanks and waterbodies, as well as provide shade to keep water cool enough to support a healthy aquatic environment.

Pesticide treatments may also be necessary in the Indian Kill preserve to address the HWA infestation there. The infestations at both preserves are light and limited in distribution, and can be contained if prompt action is taken. Left untreated, HWA normally kills trees within four to 10 years in the insect's northern range. Damage from the insect has led to widespread hemlock mortality throughout the Appalachian and southern Catskill mountains, with considerable ecological damage, as well as economic and aesthetic losses.

The two Schenectady County locations are of concern because they are within a likely pathway to the Adirondacks where hemlocks are a very important part of the ecosystem. An isolated and minor HWA infestation was discovered in Warren County in the southeast Adirondacks in July 2017. That infestation was recently treated by the same method that will be used in the Plotter Kill preserve.

To slow down and limit the spread of HWA, DEC and SCEAC's Invasive Species Committee are working together to protect hemlocks in the two county preserves. The use of insecticides is necessary to preserve the local hemlocks until DEC can successfully implement a long-term control plan that will entail the use of predators for biological control of the pest.

For more information about the project, please contact DEC's forest health information line at 1-866-640-0652, email, or visit DEC's website.

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  • Rick Georgeson
    DEC Region 4
    1130 N. Westcott Rd.
    Schenectady, NY 12306
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