In North America, the hemlock woolly adelgid is parthenogenetic, that is, there are only female adelgids and reproduction occurs without males. If you have confirmed that one or more of your hemlock trees is infested with hemlock woolly adelgid, consider treating them with a systemic insecticide. The insects feed by sucking sap from hemlock needles, and the needles die one by one. Damage to Western hemlock (scientific name Tsuga heterophylla) in British Columbia has been minor, due also to the combined action of natural enemies and host resistance. The woolly adelgid is an aphid-like insect that can grow and reproduce on all types of hemlocks, but only the eastern and Carolina hemlocks decline and die from an infestation. Its egg sacs, which look like cotton balls or clumps of snow, can be found at the base of needles. Photo courtesy of Lorraine Graney, Bugwood.org. Watch closely for hemlock woolly adelgid damage. It is also found in Asia, where the adelgid is not a serious or particularly destructive pest because populations are kept down by natural enemies (predators and parasitoids) and by host resistance. Adelgid infestations are easily recognizable by the appearance of tiny \"cotton balls\" at the base of hemlock needles. 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. The lack of an effective winged generation means that the species cannot move on its own from area to area, and must rely on being carried (by wind, animals or humans) to other places. Hemlock woolly adelgid is an aphid-like insect that attacks and kills hemlock trees. There are two generations per year, which have separate names, behaviours and appearances. 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. If nothing is done to stop the infestation, the entire branch may die. Foresters in western North America are concerned about the potential introduction of the eastern North American biotype of the adelgid into the west, as it is not known if tree mortality would be as high as in the eastern United States. If the adelgid is not controlled, infested trees will decline and eventually die, usually within four to 10 years. Western hemlock species are tolerant to the presence and feeding of the western biotype of the adelgid, and natural enemies help keep it in check. How to identify eastern hemlock trees: Eastern hemlocks have short, flat green needles with two white stripes on the underside. Efforts are underway to survey 906 hemlock-dense acres at Ludington State Park following the discovery of hemlock woolly adelgid, and with the prevention of further infection a top priority, state park and DNR officials say now is the best time for the public to keep an eye out for the invasive species. In summer, HWA will appear as black sesame seeds with a thin ring of white around them. The source of hemlock woolly adelgid in eastern North America has been reported to be a lineage of adelgids living predominantly on the southern Japanese hemlock (Tsuga sieboldii) at low elevations in southern Japan. The hemlock woolly adelgid (scientific name Adelges tsugae) was first reported in the Eastern United States in the state of Virginia in 1951, where it was likely brought in on infested nursery stock from Japan. Survey activities for this pest are ongoing to determine the extent of its spread and to foster early detection in other areas. Hemlock woolly adelgid forms round, white ovisacs on the undersides of eastern hemlock twigs. State Department of Environmental Conservation photo. Hemlock Woolly Adelgid Infested Places Order, New movement restrictions in place to prevent the spread of hemlock woolly adelgid, Hemlock woolly adelgid confirmed in Lunenburg, Nova Scotia, North American Plant Protection Organization (NAPPO) pest alert, Hemlock woolly adelgid Management Plan for Canada, D-07-05: Phytosanitary Requirements to Prevent the Introduction and Spread of the Hemlock Woolly Adelgid (. Its egg sacs, which look like cotton balls or clumps of snow, can be found at the base of needles. If nothing is done to stop the infestation, the entire branch may die. In 2017 it was detected in Southwestern Nova Scotia. Climate change is also implicated in the northward expansion of the insect. Egg production in early spring and again in early summer has a multiplier effect on the population, which if unchecked by natural enemies or other factors results in very rapid population growth.