Volunteers sought to find tree- killing bug

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Wednesday, October 22
BENNINGTON — Jim Esden, forestry specialist with the Vermont Department of Forests, Parks, and Recreation, said he needs help in spotting a certain species of Asian insect that feeds on hemlock trees.

"I just desperately need help," he said. In 2007, Esden said he made contact with Shelley Stiles, district manager for the Bennington County Conservation District, to set up two-hour training sessions to teach local citizens to spot the Hemlock Woolly Adelgid.

Feeds off and kills trees

Esden said the insect is an aphid-like creature that buries its mouth parts into the base of a hemlock needle and sucks nutrients from the twig. Over time, the twig dries out and dies. If enough adelgids cause enough twigs to die, the tree can't produce enough nutrients and dies.

He said 2007 was the first year in which the invasive species was found naturally in Vermont around the Brattleboro area. He said it had been brought in to the state before in nursery hemlocks, but those infestations had been eradicated.

So far, the adelgids have only been found in the towns of Vernon, Townshend, Jamaica, and residential parts of Brattleboro. Stiles said the Bennington volunteers, 14 in all, had been trained to look for the insects between October and July when it was most visible.

She said the insect forms a white coating over itself to protect its body from predators. The white substance has a woolly appearance, which is where the creature gets its name.

Stiles said she was attempting to contact the original group of volunteers, but had thus far not heard from any and didn't know if any were still active in looking for the Hemlock Woolly Adelgid.

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Esden said that aside from the first sighting, which he made, all adelgid infestations that have been discovered were found by citizens, not foresters or scientists. He said once an infestation was found, volunteers collected a sample of the insect and sent it in to the Department of Forests, Parks, and Recreation to be verified, as other types of insects are commonly mistaken for adelgids.

He said many infestations have been found in backyards with bird feeders or bird baths. Esden said the insect is only mobile for a short time during its life cycle, where it clings to birds and other wildlife in order to spread.

Esden said it first came to the western states in the 1920s from shipments of Eastern Hemlock. Hemlocks in the western part of the United States are resistant to the adelgid and more species of insect prey on in the west. In the Eastern United States, the hemlocks are susceptible to it and no insect preys on it heavily.

He said cold weather acted as a foil to the spread of the Hemlock Woolly Adelgid and that its recent appearance in Vermont may be due recent mild winters.

Esden's main concern was that people not overreact to the insect's presence in the state. He said cutting hemlocks in order to cash in on them before they were infected was a mistake as it would shrink the tree's gene pool. He said hemlocks with any kind of genetic resistance need to remain in order to keep infestations down.

He said hemlocks are not typically used for lumber, but are valuable in landscaping projects. They also provide an ecological service. For deer, the hemlock's branches keep snow from building up on the ground, making it easier for the animals to feed. They also shade river banks, keeping the water cool and suitable as fish habitat.

Esden said he was one of the only state officials working on the Hemlock Woolly Adelgid on a full-time basis, and was in need of trained volunteers. He said anyone who wanted to, should call (802) 885-8822. He said a training session was being held Nov. 15 at the Bonnyvale Environmental Education Center in Brattleboro.

Contact Keith Whitcomb at kwhitcomb@benningtonbanner.com.


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