Questions and answers: hemlock woolly adelgid (Adelges tsugae) detection
What is hemlock woolly adelgid
Hemlock woolly adelgid (HWA) is an aphid-like insect that attacks and kills hemlock trees by feeding on nutrient and water storage cells at the base of needles. HWA can be spread by wind, animals, and human movement of nursery stock, logs, and other wood products.
What are the movement restrictions
Areas regulated for hemlock woolly adelgid are:
- the province of British Columbia
- Digby, Queens, Shelburne, Yarmouth, Annapolis, Kings and Lunenburg counties in Nova Scotia
- the city of Niagara Falls, the township of Wainfleet, and the town of Fort Erie in Ontario
The following items cannot be moved out of the regulated areas unless authorized by the Canadian Food Inspection Agency (CFIA):
- hemlock, yeddo spruce, and tiger-tail spruce:
- plants for planting (that is, nursery stock, roots, bulbs, seeds and other plant parts)
- forest products with bark attached (that is, logs, lumber, bark chips, wood mulch)
- dried branches
- Christmas trees
- fresh decorative wreaths, foliage and branches
- firewood of all species
I need to move regulated items. What do I do
The movement of regulated items out of the regulated area is prohibited unless authorized by the CFIA. Written authorization (for example, Movement Certificate) from the CFIA is required to move regulated items from regulated areas or to transit regulated items through non-regulated areas. Please contact your local CFIA office for more information.
Where was the initial detection of hemlock woolly adelgid (HWA) in Canada
Hemlock woolly adelgid was first reported in Canada in British Columbia in the 1920s where researchers believed it has likely been present for thousands of years. HWA was detected in a forested area along the Niagara River near Niagara Falls, Ontario, in 2013 and 2015. Although affected trees were removed and disposed HWA was confirmed to be established at the site in 2019. In 2017, it was detected and found to be established in 5 counties in Southwestern Nova Scotia.
Where else is hemlock woolly adelgid found
Additional established populations have been found in Ontario in Wainfleet (2019), Fort Erie (2019), Pelham and Grafton (2022), and in Hamilton and Haldimand County (2023). In Nova Scotia, additional established populations have been found in Lunenburg County (2020), Kings County (2021) and detections in Halifax Regional Municipality (2023) and Hants County (2023) where survey activities are ongoing to determine its extent. A small population on 2 city properties in Etobicoke, Ontario, was eradicated in 2011.
How did hemlock woolly adelgid arrive in Canada
It is not known at this time how the hemlock woolly adelgid came into Canada, and the exact source will be difficult to determine. Dispersal of HWA occurs by wind, storms, hurricanes, birds, animals, and human movement of nursery stock, logs, and other wood products, including firewood.
Is hemlock woolly adelgid considered a regulated pest
Yes, import and domestic movement requirements are in place to prevent the introduction and minimize the spread of the hemlock woolly adelgid. To see the complete program, please refer to 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.
What is the potential for hemlock woolly adelgid to spread
Once established, HWA will spread naturally via wind, birds, animals, and human movement of nursery stock, logs, and other wood products, including firewood. To help prevent the spread of this pest the public is encouraged not to move potentially infested firewood and other hemlock forest products.
How does the CFIA manage emerging plant pests in Canada
If a new plant pest is introduced in Canada, the CFIA works to reduce its impact. A formal pest risk assessment may be conducted to identify its distribution, biology, pathways of spread, environmental and economic impact. If a pest is introduced, the CFIA may also conduct pest surveys to monitor it and may take action against new populations.
What are the potential economic and ecological impacts of hemlock woolly adelgid
The economic value of hemlock to the forest industry is not as high as other trees species, however, eastern hemlock can be processed for use in general construction or as pulp. Hemlock woolly adelgid, and the resulting loss of hemlock trees, has the potential to cause major ecological impacts in Canada. In many forests, hemlock serves as a foundation tree in the environment. Loss of eastern hemlock could negatively affect the health of vegetation, birds, aquatic organisms and mammals as hemlock trees serve a vital role in protecting watersheds and streams in natural forest ecosystems.
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