The bad news is that the emerald ash borer, a tree-killing beetle responsible for the destruction of 70 million trees in the United States, is still in Cattaraugus County.
The good news is that it doesn’t appear — for the moment — to be spreading, and state workers in the Southern Tier are finding new ways to combat the pesky insect that was first discovered in Michigan and turned up last June in Randolph, sparking a statewide firewood quarantine.
The state Department of Environmental Conservation announced last week that another infestation was found within the original quarantine area on private woodlands south of Interstate 86.
“The [infestation] is a mile to a mile-and- a-half from the original infestation, but it’s not new,” said Russ Biss, regional natural resources supervisor for the DEC. “It was there last year but we hadn’t discovered it.”
Biss said that’s because it can take months after an emerald ash borer infects a tree for signs to show. In last year’s case, it was three months from the time the borers penetrated the trees until they were discovered.
Emerald ash borers, which are native to Asia, leave telltale signs that differentiate them from ash borers native to the United States.
Emerald ash larvae leave a D-shaped exit hole, while less destructive native ash borers leave a round exit hole. Other signs of infestation include the top branches of a tree dying, and other branches — starved for nutrients being consumed by larvae — sprouting in abnormally low places on a tree. But Biss said the telltale sign involves peeling back the tree’s bark, where the emerald ash borer leaves an S-shaped imprint as opposed to the straight imprint of the native borer.
It’s that strategy of pulling back tree bark that has spurred a new way of dealing with the insect. Crews from the U. S. Department of Agriculture continue to hang purple traps within a six-to eight-mile radius of suspected infestation sites or ash-heavy areas. But Biss said that because the traps depend on the pure chance that a borer might land in them, they are only about 5 percent effective.
When an infestation was found, workers cut down the infected trees and chipped the wood into fine pieces.
“The good thing about that strategy is that it kills the larvae and also the grown borers, so it’s getting rid of two generations,” he said.
But one problem with the strategy was that trees that were cut down allowed for emerald ash borers to escape before they could be sent through a grinder. Crews then came up with the idea of “girdling” a tree—stripping one tree of all its bark before cutting down other trees, with the hope that borers from the cut-down trees would be attracted to the “girdled” tree.