Hemlock Woolly Adelgid found in Lake and Geauga County
Hemlock woolly adelgid, Adelges tsugae, is an invasive insect in eastern North America.
1276002 Michael Montgomery, USDA Forest Service, Bugwood.org
It feeds on Canadian Hemlock, Tsuga Canadensis. The insect was discovered last summer feeding on a mature stand of Hemlocks on Little Mountain on a property located on the grounds of Holden Arboretum. Although it is uncertain how the adelgid got there, it is thought that it arrived on birds migrating north.
0718057 John A. Weidhass, Virginia Polytechnic Institute and State University, Bugwood.org
Because of the discovery, both counties have been quarantined. Canadian Hemlocks grown in nurseries located in Lake and/or Geauga County, Ohio will have special requirements and restrictions on movement of their hemlock nursery stock. The Ohio Department of Agriculture will put a protocol including inspection and treatment in place for the 2018 growing season.
Hemlock woolly adelgids are small and are most notable by their woolly covering. The insect has two generations per year and growth occurs from fall through late spring.
1276002 Michael Montgomery, USDA Forest Service, Bugwood.org
Insects in summer are inactive and scarcely visible at the bases of needles as black dots, sometimes referred to as looking like a speck of black pepper at the base of the petiole.
Woolly masses develop in October and are present thereafter through June of the following year.
1520083 USDA Forest Service - Region 8 - Southern , USDA Forest Service, Bugwood.org
In the eastern USA, Adelges tsugae is killing eastern hemlocks (Tsuga canadensis [L.] Carrière) and Carolina (Tsuga caroliniana Engelm.) in large numbers from Connecticut south along the Appalachian Mountains. From Massachusetts north, or at high elevations, tree mortality has been slowed by higher rates of mortality of adelgids in winter due to low temperatures.
4588707 Ignazio Graziosi, University of Kentucky, Bugwood.org
Chemical control includes the use of Imidicloprid by trunk injection.
1344047 Great Smoky Mountains National Park Resource Management , USDI National Park Service, Bugwood.org
1344148 Great Smoky Mountains National Park Resource Management , USDI National Park Service, Bugwood.org
Imidicloprid can also be applied to the soil as directed by the label.
1344057 Great Smoky Mountains National Park Resource Management , USDI National Park Service, Bugwood.org
The systemic insecticide has been found to be effective in controlling the adelgid and is most effective when applied in the fall.
A biological control program is in progress against this pest, based on specialized predatory beetles that feed only on adelgids, collected in western North America (Laricobius nigrinus Fender) or China/Japan (species of Laricobius and various Scymnus ladybird beetles).
1294058 Suzanne Lyon, University of Massachusetts, Bugwood.org
To date, releases have not demonstrated any reductions in adelgid densities from predators. Populations of L. nigrinus have become well established and abundant in some areas of western North Carolina.
More information is available about Hemlock Woolly Adelgid at the following sources:
Hemlock Woolly Adelgid - USDA Forest Service
Hemlock Woolly Adelgid Survey in Georgia - Georgia Forestry Commission
Biological Control of Hemlock Woolly Adelgid - USDA Forest Service
Hemlock Woolly Adelgid in Georgia -
Proceedings: Hemlock Woolly Adelgid in the Eastern United States Symposium - USDA Forest Service
Pest Alert - USDA Forest Service
Hemlock Woolly Adelgid Action Team - Southern Appalachian Man and the Biosphere
Pest Notes - The Nature Conservancy
