ALBANY, N.Y. — The invasive beetle that has destroyed tens of millions of ash trees over the past decade has been found east of the Hudson River for the first time, marking its closest known threat to New England, researchers in New York told The Associated Press Wednesday.
But the discovery of an emerald ash borer infestation in the Dutchess County village of Rhinecliff last month may signal a victory in the battle to stem the pest’s spread: Foresters believe the colony was caught less than a year after it got established, a big step given that the beetle can go unnoticed for years.
The larval beetle tunnels under the bark, eventually destroying a tree without any sign until its foliage yellows and dies. The shiny green adults are only about half an inch long and tend to fly well above the ground, making them hard to spot.
“It’s rare that infestations are found this early,” said Nate Siegert, a U.S. Forest Service entomologist who has been working in Rhinecliff this month. He credited state Department of Environmental Conservation foresters for taking steps that led to the discovery.
Ash trees, prized as a commercial hardwood and a feature in urban plantings, have been ravaged through much of the Midwest and into the mid-Atlantic and Northeast since the Chinese beetle was first discovered near Detroit in 2002. Borer infestations were found in western New York in 2009, but experts say the Hudson Valley colony could have started years before that, possibly after catching a ride across the state in a load of wood.
The main population has been spreading gradually at a pace of about 2 to 3 miles a year, but “satellite” colonies leapfrog ahead, mostly by hitchhiking in loads of logs or firewood.
Maine has been on alert for the pests for a number of years, and has largely banned the importation of firewood to state campgrounds in an effort to stop the invaders. Last fall, a search for invasive bugs suspected of arriving in Maine came up empty, pleasing state Forest Service officials.
Using traps from York to Limestone containing scents of the targeted insects, the Maine Forest Service entomology staff found none of the most dangerous invasive insects they believed were threatening the state’s forests. Out of the 2,600 trap samples processed this past year, the Forest Service found no Asian longhorned beetles or emerald ash borers.
New York became a leading edge for research and control efforts after a major infestation was discovered on the west shore of the Hudson in 2010, about 150 miles east of colonies discovered elsewhere in New York since 2009.
Researchers set out purple traps and stripped bark from trees last year, eventually mapping finds of beetle larvae in a 225-square-mile area running north from just below Kingston, bounded on the east by the river and parts of the Catskills in the west.
Jeff Rider, a DEC supervising forester, said 28 “trap” trees on the east shore were also girdled — stripped of a band of bark — to attract any beetles that may have made it across.
Three of those trees just below the Kingston-Rhinecliff Bridge about 25 miles from the Connecticut and Massachusetts borders were found with small infestations in March, he said. That sent researchers ranging through a 3-mile radius around each, taking samples from 78 other ash trees. Rider said none of those trees was infested, but an additional 100 trees have now been girdled in the area.
He said plans are being made to quarantine moving ash material in Dutchess County, but he thinks that may be limited to particular towns, not entire counties like across the river. People can be fined for moving firewood 50 miles beyond its origin, a regulation meant to thwart ash borers and other invasive pests.
Rider thinks the latest infestation involved adults that crossed the river during last summer’s flying season.
Forestry experts in New England have been watching for any sign of the ash borer, typically relying on the familiar purple traps.
“They’re gearing up, knowing they’re eventually going to have it,” Rider said. “We’re just trying to buy them some time.”
“This is a battle worth fighting,” said Chris Martin, the state forester in Connecticut. “The ash tree resources in New England are phenomenal.”