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Hemlock Woolly Adelgid

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Hemlock Woolly Adelgid
Scientific Name:
Adelges tsugae (Annand) (Annand 1928)
Common Name:
Hemlock Woolly Adelgid (HWA)
Hemlock Woolly Adelgid, Adult with wax removed - Michael Montgomery USDA, Forest Service
Native To:
Date of U.S. Introduction:
Discovered on the West Coast in the 1920s, but it is disputed whether this was an introduced or native population; an introduced population was discovered on the East Coast in the 1950s (Havill et al. 2006; Orwig et al. 2003)
Means of Introduction:
Destroys Eastern hemlock trees (Tsuga canadensis) (Orwig et al. 2003)

Distribution/Maps/Survey Status




Selected Resources

The section below contains selected highly relevant resources for this species, organized by source. To view all related content for this species, click on "View all resources for species" in the top left of this page.


Nature Conservancy. Don't Move Firewood.
IUCN. Species Survival Commission. Invasive Species Specialist Group.

New York Invasive Species Clearinghouse.

Texas State University System. Texas Invasive Species Institute.

Federal Government

State and Local Government

Wisconsin Department of Natural Resources.

Maryland Department of Agriculture.

Ohio Department of Agriculture. Plant Health.

Pennsylvania Department of Conservation and Natural Resources.

Maine Department of Conservation. Maine Forest Service. Forest Health and Monitoring Division.

Tennessee State Government.
New York Department of Environmental Conservation.


University of Minnesota.
IPM of Midwest Landscapes is available for educating growers, landscapers, managers, and consumers in the principles of IPM and its application to managing the over 150 common insect species in Midwest landscapes.
University of Maryland. Cooperative Extension. Home and Garden Information Center.
Cornell University. Cooperative Extension of Suffolk County. Horticulture Diagnostic Laboratory.
See also: Tree and Shrub Insect Pests for more fact sheets.
Columbia University. Center for Environmental Research and Conservation.
Pennsylvania State University. Cooperative Extension.
Cornell University. Forest Health and Invasive Non-native Forest Pests.
Rutgers Cooperative Extension. New Jersey Agricultural Experiment Station.