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Westmoreland

Learn about the invasive pest targeting Pennsylvania's state tree, the Eastern hemlock

Patrick Varine
| Wednesday, Feb. 7, 2018, 5:42 p.m.
A Hemlock tree that shows signs of unhealthy branches is seen at Bear Run Nature Reserve on Wednesday, July 12, 2017 in Fayette County. The Hemlock woolly adelgid, an invasive species of insect that feeds on the sap of Hemlocks, is the culprit in the death of many of the Hemlocks in western Pennsylvania. A presentation on the invasive pest will be held Feb. 15, 2018, in Greensburg.
Shane Dunlap | Tribune-Review
A Hemlock tree that shows signs of unhealthy branches is seen at Bear Run Nature Reserve on Wednesday, July 12, 2017 in Fayette County. The Hemlock woolly adelgid, an invasive species of insect that feeds on the sap of Hemlocks, is the culprit in the death of many of the Hemlocks in western Pennsylvania. A presentation on the invasive pest will be held Feb. 15, 2018, in Greensburg.
A branch of an Eastern Hemlock tree Wednesday, July 12, 2017 at Bear Run Nature Reserve in Fayette County. Though difficult to see, a small white insect called the Hemlock woolly adelgid is evident on the branch, and is the major cause of Hemlock damage in western Pennsylvania.
Shane Dunlap | Tribune-Review
A branch of an Eastern Hemlock tree Wednesday, July 12, 2017 at Bear Run Nature Reserve in Fayette County. Though difficult to see, a small white insect called the Hemlock woolly adelgid is evident on the branch, and is the major cause of Hemlock damage in western Pennsylvania.

Pennsylvania's state tree is under attack, and the state's Department of Conservation and Natural Resources wants as many people as possible to know.

The hemlock woolly adelgid, an invasive insect native to eastern Asia, was first identified in Pennsylvania in 1973 and in Westmoreland County in 2006. It has also been discovered in 18 other states from Oregon to the Carolinas, according to the Penn State Agricultural Extension.

The insects' namesake white, woolly overwintering sacks are visible in winter and early spring on the underside of hemlock branches.

Jessica Salter, a DCNR service forester, will speak Feb. 15 at the Westmoreland Woodlands Improvement Association meeting, set for 6:30 p.m. at the J. Roy Houston Conservation Center, 218 Donohoe Road, Greensburg.

Once in a hemlock tree, the adelgid crawls to the base of a hemlock needle and begins to feed, according to a February 2018 article published by the agricultural extension.

To feed, the adelgid inserts its feeding stylets, or mouthpiece, into the underside of the base of a needle. The adelgid feeds on the tree's nutrients. Feeding causes the needles to die, turn gray, and drop from the tree. Buds are also killed by the feeding, resulting in no new growth on infested branches. Dieback of major limbs occurs within two years. Branch dieback progresses from the bottom of the tree up to the top. In many cases, the tree eventually dies.

For more, see the association's website at WestmorelandWoodlands.org .

Patrick Varine is a Tribune-Review staff writer. Reach him at 724-850-2862, pvarine@tribweb.com or via Twitter @MurrysvilleStar.

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