A Modern Day Lorax Saving Our Hemlocks
January 15, 2009 by Don Gentle
Nearly a year ago the hemlocks at Camp High Rocks were in big trouble! A tiny fluid-feeding insect known as the hemlock woolly adelgid (HWA) infested the trees and began a slow feeding death on most all of the hemlocks here at camp.
The HWA larvae live at the base of the needles, feeding on the tree and destroying existing foliage as well as suppressing new foliage. The tree begins to lose its green, becoming first grayish, then barren, and finally dead. High Rocks has hundreds of Hemlocks, mostly along the banks of our many streams. The most notable hemlock in camp is the one that holds the sign at the base of the camp road. The roadside tree, as well as many of the hemlocks on our property, were in bad shape! The future of our hemlocks would have been certain destruction.
Dr. Patrick Horan, is professor at UGA, who has been developmental in the biological control of the woolly adelgid. He has been working with many people in the Southeast to help save the hemlocks, mostly through the introduction of a beetle known as the Sasajiscymnus tsugae, aka Sassie beetle, which feeds primarily on the HWA. While chemical treatment may work if you have a hedge or small group of trees on your property, you cannot treat every tree in the forest every three years and we were not a big fan of all that synthetic chemical in the forest soil.
So, last spring Patrick and Hank decided on several spots to release the Sassie beetles. These spots would allow for plenty of beetle production, as well as HWA destruction. The beetles work their way down stream feeding and breeding. Patrick came back about a week ago to see how our experiment is going. He was very impressed with the new growth at the crown of the hemlocks and the reduced amount of HWA egg sacks at the base of the needles. The beetles will never completely get rid of the adelgid, but it will keep it under control to allow the tree to flourish.