Hemlock Wooly Adelgid invasion thwarted

A visitor from from Vermont with a sound knowledge of forestry and a keen eye for trouble spared the region the ravages of the Hemlock Wooly Adelgid, an insect that has devastated stands of hemlock throughout much of the east coast.

Andy Fast, the Belknap County Forester with the University of New Hampshire Cooperative Extension Service, said yesterday that the woman, who chose not to be identified, was visiting relatives in Alton Bay when she spotted what she believed was Hemlock Wooly Adelgid on a tree in her family's yard. He said that the woman told him of her suspicion and he went to see for himself then alerted Kyle Lombard, an entomologist who coordinates the Forest Health Program at the New Hampshire Division of Forests and Lands. Lombard confirmed the presence of Hemlock Wooly Adelgid as the first appearance of the pest in Belknap County and the northernmost confirmed infestation in the state.

Hemlock Wooly Adelgid is a small aphid like insect, less than one-sixteenth of an inch in size, introduced to the Pacific northwest from Asia in the 1920s, which has spread along both the west and east coasts. While it has done little damage to western and mountain hemlocks, it has killed thousands of eastern and Carolina hemlocks during the past 50 years.

Reddish brown when hatched, the young crawlers cover themselves with a fluffy white wax, from which they take their name. They settle on the underside of young hemlock branches at the base of the needles where they suck the sap from the twigs, draining the foliage of moisture and color. A heavily infested tree may die within four years.

While hemlocks in southern New England have been decimated in three or four years Fast said that some speculate that the colder winters limit infestations of the insect and slow the deterioration of the hemlocks in New Hampshire.

Fast said that Lombard contained and treated the infestation in Alton Bay with an insecticide as well as inspected adjacent properties. "We expect it will be fully eradicated," he said, added that a forester will visit the site next year. He called the discovery of the pest "a shining example of an informed resident making an incredible contribution to the county and its natural resources."

Southern Hillsborough and Rockingham counties have been designated as "internal quarantine areas," from which hemlock cannot be transported without being certified as free of the Hemlock Wooly Adelgid. Although used as a source of pulp, hemlocks have relatively little commercial value, but in dense stands provide valuable cover for deer in winter.