Hemlock woolly adelgid – Adelges tsugae (Annand)

Hemlock woolly adelgid is an aphid-like insect that attacks and kills hemlock trees. Its egg sacs, which look like cotton balls or clumps of snow, can be found at the base of needles. It can be spread by wind, animals, and human movement of nursery stock, logs, and other wood products including firewood.

Hemlock woolly adelgid was first reported in Canada in British Columbia in the 1920s and in the United States (Virginia) in the 1950s and has been establishing itself along the eastern coast of the United States. In 2017 it was detected in Southwestern Nova Scotia. As part of the 2019 detection survey for HWA, the Canadian Food Inspection Agency (CFIA) confirmed the presence of hemlock woolly adelgid in a forested area along the Niagara River near Niagara Falls, Ontario where it was previously confirmed between 2013 and 2015. It was also confirmed in an area in Wainfleet, Ontario. Survey activities for this pest are ongoing to determine the extent of its spread and to foster early detection in other areas.

Detections and regulated areas

• Hemlock woolly adelgid Infested Places Order
• New movement restrictions in place to prevent the spread of hemlock woolly adelgid
• Hemlock woolly adelgid confirmed in Nova Scotia
• Questions and answers: hemlock woolly adelgid detection in Nova Scotia

Resources

• Pest fact sheet
• North American Plant Protection Organization (NAPPO) pest alert
• Hemlock woolly adelgid Management Plan for Canada
• Poster: hemlock woolly adelgid
• Don't move firewood campaign

Policy directive

• D-07-05 - Phytosanitary requirements to prevent the introduction and spread of the hemlock woolly adelgid (Adelges tsugae, Annand) from the United States and within Canada