The distribution of the hemlock woolly adelgid in Canada

Abstract

AbstractThe hemlock woolly adelgid,Adelges tsugaeAnnand (Hemiptera: Adelgidae) has distinct native and invasive populations in Canada. On Canada’s west coast the adelgid is a native insect feeding on western hemlock,Tsuga heterophylla(Raf.) Sarg. and mountain hemlock,Tsuga mertensiana(Bong.) Carrière (Pinaceae). In eastern Canada, the adelgid is an invasive species that attacks and kills eastern hemlock,Tsuga canadensis(L.) Carrière (Pinaceae). We obtained all records ofA. tsugaein institutional and public databases and develop updated range maps, phenologies and dispersal estimates for the species in British Columbia and eastern Canada In British ColumbiaA. tsugae’s distribution is centred around the lower mainland and on Vancouver Island but with populations in the interior and along the Pacific coast that have been poorly explored and which could be sources of biological control agents to manage invasive populations in the east. In eastern Canada, the adelgid has invaded all of southern Nova Scotia, portions of the Niagara region in Ontario as far west as Hamilton, and at least one site on the north shore of Lake Ontario. No populations have been found in New Brunswick, Quebec or Prince Edward Island. Finaly, we estimated the rate of spread in Nova Scotia at 12.6 ± 8.2 to 20.5 ± 27.21 km/year.