On the Lookout for a Tree-Eating Invasive

May 19, 2011

The Emerald Ash Borer is an invasive insect from Asia that has killed more than 50 million ash trees in the U.S. in the past decade. The U.S. Department of Agriculture is setting more than 60,000 traps in 48 states, including Connecticut, to look for the beetle. 

If you spot a purple triangular box hanging in the canopy of a tree it is not an art installation. It’s a trap designed to find the voracious Emerald Ash Borer. Although the purple boxes can capture the beetle, they’re being used in Connecticut not so much as a trap, but as a detection device. The insect was first discovered in Michigan and Ontario ten years ago. Since then it has spread to at least 15 states including New York. And to Quebec, just north of Vermont.  But it hasn’t been seen in Connecticut yet.  Patty Douglass of the U.S.D.A. says the government wants to find the leading edge of the Emerald Ash Borer infestation. 

“They tend to go to the tops of the trees first. Their exit holes are very tiny, like a quarter of an inch. So it’s very hard to see the effects of the Emerald Ash Borer until you have a pretty heavy infestation. So we’re doing the best we can with these traps to try to do early detection.”

The larvae of the insect feed on ash wood and block the flow of water and nutrients, killing the trees. It isn’t possible to eradicate the pest. But if it is found here the state and the federal government would put a quarantine around the infested area, outlawing the movement of wood to stop the insect from moving into other states. More than 900 of the two-foot long purple traps are being hung in trees in Connecticut.