Canadian Forest Service Publications
Sampling techniques to detect canopy infestations of the hemlock woolly adelgid. 2021. Fidgen, J.G.; MacQuarrie, C.J.K.; Turgeon, J.J. Natural Resources Canada, Canadian Forest Service, Great Lakes Forestry Centre, Sault Ste. Marie, Ontario. Frontline Technical Note 118. 4p.
Issued by: Great Lakes Forestry Centre
Catalog ID: 40517
Availability: PDF (download)
Plain Language Summary
Hemlock woolly adelgid (Adelges tsugae Annand) has recently invaded Canada and is threatening the survival of eastern hemlock. An important part of the management of the hemlock woolly adelgid is effective detection of populations while they are still small and less costly to treat. This note describes two new detection techniques: ball sampling and sticky trapping, which consistently detect low-level infestations of the adelgid. Ball sampling involves shooting a ball fitted with Velcro into the hemlock canopy to detect the ‘wool’ produced by the adelgid, whereas sticky traps intercept the mobile stage of the insect at ground level when it falls from the trees. Ball sampling and sticky trapping are most effective when at least 2% of the twigs on a tree or at least 2% of the trees in the stand have adelgids.