The USDA Forest Service conducted an experimental release of the predatory beetle, Pseudoscymnus tsugae, (Pt beetle) at Joyce Kilmer Memorial Forest, Wednesday April 28th, as part of an ongoing effort to save the Eastern and Carolina Hemlocks in western North Carolina from the hemlock woolly adelgid. A number of the ancient, old growth hemlocks in Joyce Kilmer Memorial Forest are now heavily infested, and if left untreated, will likely be killed in a few years by this foreign pest. Joyce Kilmer Memorial Forest is one of the very few remaining large tracts of virgin old growth forest in the Appalachians and contains many trees, including hemlock, that are 20 feet in circumference and over 400 years old.
USDA Forest Service health protection specialists, tree climbers from Appalachian Arborists, and members of the Partners of Joyce Kilmer-Slickrock Wilderness participated in Wednesday's beetle release. Tree climbers from Appalachian Arborists, of Asheville, scaled 140-foot tall hemlocks along the Joyce Kilmer Memorial Loop Trail to release approximately 6,000 PT beetles into the upper branches of infested hemlocks.
The Pt beetle released Wednesday in Joyce Kilmer Memorial Forest is one of several predatory beetles that are currently being tested in the Southern Appalachians to see if they will be effective in reducing the damage caused by the hemlock woolly adelgid. This adelgid is an alien pest native to Japan that was accidentally introduced into this country in the 1920s. It has no known natural enemies here, and if left unchecked, has the potential to kill off most of the native hemlocks in the Southern Appalachians.
In this photo, Appalachian Arborists Brian Hinshaw on left and Mike Riley on right, release beetles in Joyce Kilmer Forest.
Pt beetles, and two other similar predatory beetles, are now being raised in a number of laboratories including, the State of North Carolina Agriculture Department, Clemson University, the University of Tennessee, and Virginia Tech, but supplies are still extremely limited. The Pt beetle (like the adelgid also originally from Japan) is a tiny black ladybird beetle about the size of a poppy seed. It specifically attacks adelgids and both the larvae and adult beetles feed voraciously on all life stages of HWA. Its life cycle is well synchronized with that of the adelgid, and it completes at least two generations each year in the field. The beetle has shown no undesirable traits that would cause it to be a nuisance or otherwise poor candidate for release. The USDA granted a permit for its release in 1995.
Photos by Will Blozan, Appalachian Arborist, Asheville, NC
