U.S. Forest Service efforts to save Hemlocks

The hemlock woolly adelgid (HWA) is an alien pest native to Japan that was accidentally introduced into the United States in the 1920's. It was first detected in Rabun County Georgia in 2002 and is spreading west and south throughout northern Georgia. Hemlock woolly adelgid can be identified by the presence of white wool-like sacs on the underside of the outermost branch tips of hemlock trees.

Over the last several years, the Chattahoochee National Forest has been actively involved in efforts to save Georgia's hemlocks from the hemlock woolly adelgid. "We realize we can't save all the hemlocks from this infestation," stated Ron Stephens, forester on the Chattahoochee-Oconee National Forest, "but we hope to save enough to preserve the genetic diversity within the hemlock population."

One method being used involves injecting a chemical into the soil at the base of the tree. The chemical (Imidicloprid) is taken up by the roots of the hemlocks and provides protection from damage by the insect. In the spring of 2006, approximately 1,000 trees in 26 separate groups were chemically treated on National Forest land in Towns and Union Counties.

Another control method being used is the release of a predator beetle (Sasajiscymnus tsugae) that only preys on the hemlock woolly adelgid. Between March and June 2006, the Forest Service released approximately 87,000 of these adult predator beetles and/or their eggs in 32 locations on National Forest lands in Towns and Union Counties. This is one of several beetles that are currently being tested to see if they will be effective in reducing the damage caused by the adelgid. The beetles were provided by laboratories at Clemson University and Young Harris College.

The Young Harris College Beetle Laboratory is operated under the direction of Professor of Biology, Paul Arnold. In its first year of operation, Dr. Arnold's lab produced over 50,000 beetles for release on the National Forest. Dr. Arnold was recently recognized by the Chattahoochee National Forest for his significant contribution in support of the Forest Service's HWA control program. In addition, the Forest Service has donated a surplus walk-in cooler to Young Harris College to be used at the beetle-rearing facility.

The operation of the Young Harris Laboratory is primarily through private donations and assistance from student and local community volunteers. Dr. Arnold can be contacted at ptarnold@yhc.edu. For further information on the effort by the Forest Service to control hemlock woolly adelgid in Georgia contact Jim Wentworth at (706) 745- 6928 or jwentworth@fs.fed.us