Hemlock woolly adelgid is an invasive pest that has been monitored in Canada since the 1950s. Recently, it has become more of a concern as we are finding increased populations in southern Ontario. Native to Japan, there are no known natural enemies for hemlock woolly adelgid in Canada and will target all 9 species of hemlock (Tsuga). Defoliation starts from the tips of branches and if not controlled, tree fatality is anticipated within 4-10 years depending on the trees health, age and growing conditions.
Facts about hemlock woolly adelgid
Scientific name, adelges tsugae, the hemlock woolly adelgid is parthenogenetic. Meaning reproduction occurs without males and there are only female adelgids. The insect has 3 forms and goes through 2 generations per year. Commonly easily identified in its adult stage, when its body is covered with white “woolly like” waxy threads. Quite small in size, they are also excellent hitchhikers, and travel usually through wind, birds, wood and humans.
Hemlock woolly adelgid solutions
At Arborwood Tree Service, we offer programs to efficiently suppress, protect and recover Hemlocks from hemlock woolly adelgid infestations. Control measures included systemic and foliar applications. Systemic applications are most effective and appropriate in the months of spring, from March to June. Fall applications, through the months of September to December can be applied as well. Systemic applications are highly effective for control of hemlock woolly adelgids and provide control for up to 2 years.
Future prospects for the hemlock woolly adelgid in Ontario
With no natural enemy in Ontario, hemlock woolly adelgid populations are estimated to increase if not properly controlled. Groups such as the Canadian Food Inspection Agency and Canadian Invasive Species Centre are regulating and monitoring sites across Canada. There are studies being conducted to see if there are any non-invasive insects in Canada that will feed on the hemlock woolly adelgid and as well any fungal pathogens for biological control. It is predicted that the state of our hemlocks in Canada will rely on the mixture of natural control practices and properly timed treatments. As a homeowner, the best you can do to help the spread is to keep bird feeders away from hemlocks, do not move firewood, keep an eye out and report if you have identified a hemlock woolly adelgid.