Invasive insect found in Adironadacks


GLOVERSVILLE — The bad news is that an invasive insect in the Adirondacks is out to kill hemlock trees. The good news is that natural predators are gradually being introduced which can fight it.

And the public can help.

The first infestation of hemlock woolly adelgids recently was discovered in the Adirondack Park—two trees on Prospect Mountain near Lake George. The trees were chemically inoculated and sprayed by the state because, in four years, the one-milimeter, aphid-size adelgids can kill a tree by making it unable to draw up water and nutrients from its roots.

The Foothills Chapter of the Adirondack Mountain Club is sponsoring a workshop today from 10 a.m. to 4 p.m. at the Paul Nigra Center for Creative Arts, 2736 Route 30, to educate the public and teach how people who frequent the woods can help. Participants are limited to 30.

“We have a opportunity to save a tree that is one out of seven or 10 of the trees in the southern Adirondacks,” said Neil Woodworth, executive director of the statewide Adirondack Mountain Club.

Besides in-house presentations, participants in the workshop will travel to the non-infested Peck Hill State Forest to learn how to recognize the signs of adelgid attacks and report it to a statewide tracking system. This will allow the state to treat the trees chemically as quickly as possible.

“The public will play a major role in detecting this and protecting the trees,” he said.

The lower Hudson River valley and Catksill regions as well as the Great Smokey Mountains in the Applachians have been among the areas already been ravaged by the insect. The adelgids reportedly are known to travel on the feet and legs of birds, but possibly attached to people or vehicles.

The damage of the adelgids goes further than just the trees since hemlocks reduce erosion along brooks and keep the water cooler, Woodworth said. That’s important because “brook trout need cool, clear water to reproduce,” he said.

While chemical treatment of hemlocks is a stopgap measure, the chemical treatment of millions of trees would be a mammoth project, Woodworth said.

Fortunately, Mark Whitmore, forest entomologist (insect expert) in the department of natural resourses at Cornell University in Ithaca, has been introducing two natural predators of the adelgids in the state—a beetle called Laricobious nigrinus, dubbed “Larry” for short, and the silver fly.

Adelgid is native to Japan, China and the Pacific Northwest, Whitmore said, but it is kept under control in the Northwest by the two natural predators.

Also good news is that “Larry” and the silver fly do not harm any other species in the Northwest. That’s something scientists have to be careful about because the misguided introduction of species into non-native areas in the past, such as the mongoose in Jamaica and the cane toad in Australia, have sometimes wreaked unexpected havoc on ecosystems, said Whitmore.

Whitmore, a specialist in biological control of invasive species, said the effectiveness of “Larry” and the silver fly is “a numbers game.” He and his colleagues at Cornell are working hard to breed as many of these predators as possible to make a significant impact on the adelgids. He has released between 100 to 200 at a time in nearly 20 locations in the state, but he has to breed many more.

Chemical treatment of hemlocks is a way of “buying time while we effect biological control” — a critical mass of the adelgid’s predators needed to save the hemlocks.

Funding by the U.S. Forest Service has recently been supplemented by a $1 million state grant to aid the painstaking work, he said.

Caroline Marschner of Cornell’s New York State Hemlock Initiative is hoping the residents of the Adirondacks work together to stop the adelgids. “New York State has more eastern hemlocks than any other state…and the Adirondacks have the highest concentration of hemlocks in New York,” she said.

“We have the opportunity here in the Adirondacks to preserve our iconic hemlock forests through effective and timely management.”

By Patricia Older

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