Invasive beetle now east of Hudson

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.

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.

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.