Courtesy of Tom McAvoy from the Dept of Entomology at Virginia Tech:
In 2008 we continued monitoring hemlock woolly adelgid at Mountain Lake. Our monitoring indicated that hemlock woolly adelgid numbers increased since 2007. Therefore, approximately 75 infested trees were treated with imidacloprid using soil injection. These trees were on the east side of the lake between Indian and Lower Jungle Trails. Hemlocks on Blueberry Ridget and around the hotel had no hemlock woolly adelgid. A total of 486 trees have been treated since this program in 2001. While 50 (10%) of the treated trees have died, 12, of the 55 untreated trees that have been monitored have died. This is a 22% mortality for trees that were never treated. Treating the hemlocks has saved a significant number of trees. Most of the mortality has occured along the Indian Trail.