Hemlock woolly adelgid found on nearly 250 acres along Lake George

By Gwendolyn Craig

The second recorded infestation of hemlock woolly adelgid in the Adirondack Park has spread far beyond a Lake George campsite where it was first discovered.

The state Department of Environmental Conservation announced Thursday that surveyors found the invasive bug on nearly 250 acres along 1.5 miles of shoreline on the eastern side of the lake in the towns of Dresden and Fort Ann.

DEC will treat the infected trees with an insecticide this fall, according to a press release.

Mark Whitmore, a forest entomologist at Cornell University and the New York State Hemlock Initiative, is partnering with the state, the Lake George Land Conservancy and the Adirondack Park Invasive Plant Program on analyzing and treating the site.

“This is a wake-up call because hemlocks are huge in the Adirondacks,” Whitmore said. “It is the most common shoreline tree on Lake George, period.”

A camper first discovered and reported the infestation in August at the Glen Island Campground. Since then, DEC staff and partners have surveyed for more than 500 hours along about 16 miles of shoreline on Lake George. Whitmore said the adelgid was found in Paradise Bay, too, a popular cove on Lake George where boaters and swimmers often congregate.

Birds may have spread the adelgid, according to the DEC. Whitmore said once an adelgid hatches and is ready to move, its size is less than a quarter of a millimeter. It’s small enough to float on the wind or hitch a ride on an animal.

Surveying will continue to see if more trees are impacted, according to a press release.

Hemlock woolly adeglid is native to eastern Asia. The tiny bug feeds on hemlock twigs. It takes four to 10 years for them to kill a tree, which Whitmore said is both good and bad.

“It kills the buds first, so the tree might still have its needles, but it doesn’t produce any new needles, so that’s the insidious thing,” Whitmore said. “It looks green. It looks just fine to the untrained eye, until it’s too late.”

Some of the oldest trees in New York are hemlocks, the DEC said. They can live for more than 700 years. They are important for protecting water quality by preventing erosion along shorelines. Hemlocks are also instrumental in protecting native brook trout, by shading waters and keeping them cool.

Whitmore said he was hopeful they could curtail the infestation. The DEC said it will use an insecticide at the base of the infected trees. The same insecticide was used the first time hemlock woolly adelgid was found in the Adirondack Park, in 2017 on Prospect Mountain in Lake George. Whitmore said that infestation was very different, however, as surveys showed only three infected trees.

The DEC and its partners are also determining whether to introduce an insect that feeds on adelgids, something Whitmore has studied for years in his Cornell lab.

Signs of an adelgid infestation include white woolly masses on the underside of hemlock branches, gray needles and needle loss. Report possible infestations to New York’s invasive species database nyimapinvasives.org or contact your local invasive species management organization: dec.ny.gov/animals/47433.html.