Caterpillars harm N.H. trees; Maine on watch

CONCORD, N.H. – A 2-inch-long caterpillar with a row of white dots on its back is costing New Hampshire’s timber industry millions of dollars and could take a toll on next year’s maple syrup industry as well.

Kyle Lombard, forest health specialist with the state’s Division of Forest and Lands, said the tent caterpillar has infested about 70,000 acres. The insects eat the canopies of northern hardwoods, which doesn’t kill the trees but weakens them. The caterpillars have affected mostly forests around Mount Sunapee – and they’ve taken away leaves during the spring and summer.

Last year, only about 10,000 acres were affected in New Hampshire.

Lombard said tapping affected maples for syrup further stresses the weakened trees. He said foresters also have been forced to delay harvests in affected areas. Lombard estimates the insect has cost the timber industry as much as $5 million.

“They’re in here, and they’re multiplying, and they’re moving,” Lombard said.

He said the infestation probably was carried by the wind from Vermont, where 400,000 acres were defoliated this year.

To kill its caterpillars, Vermont sprayed 1,600 sugar maples with a bacterial insecticide.

In Maine, state officials are monitoring the pest and using traps in rural areas to assess how prevalent they are. Small areas have been affected, but nothing on a large scale, said Dave Struble, the state entomologist.

“At this point, we don’t have any outbreak, but we continue to monitor the situation,” he said.