Ontario’s oaks threatened

The City of Windsor is hoping to deter a potential invasion by the deadly oak wilt fungus, which can kill a mature tree in a single season. Oak wilt is a vascular disease that grows on the outer sapwood, restricting the flow of water and nutrients. Currently, there’s no cure. According to the Windsor Star, the disease was first reported in Michigan in the 1940s and has destroyed millions of trees there, including the Shumard oak, which is a Species of Concern in Ontario. Two years ago, it was discovered just across the border, in Michigan’s Belle Isle Park, about a half-kilometre from Windsor’s shoreline. It has not yet been reported in Ontario. In a proactive move, Windsor has partnered with BioForest, a private consulting firm, the Invasive Species Centre (ISC), and the Canadian Food Inspection Agency (CFIA) to prevent its introduction into Ontario. Oak wilt workshop ISC Partnership and Science Manager David Nisbet said the ISC hosted an oak wilt workshop for the MNRF, CFIA, OFAH, and the City of Windsor in Windsor in September 2017. Among other things, the groups were shown how to train volunteers to identify and report oak wilt. The disease spreads from infected trees to uninfected trees of the same species through root-to-root contact. Sap-feeding nitidulidae beetles can also move spores from infected trees to healthy trees, and the fungus can be spread by transporting infected firewood. “A first indication of the disease is the top portion of the oak’s foliage turning brown, the bottom green, and the tree dropping leaves mid-summer,” said Invading Species Awareness Program Outreach Liaison Kate Powell. The Michigan Department of Natural Resources advises against pruning oak trees during the growing season as this attracts beetles. If pruning must occur, or if a tree is injured, they recommend immediately applying a thin layer of wound paint. Anyone seeing evidence of oak wilt is asked to call the CFIA, MNRF, City of Windsor, Essex Region Conservation Authority, or phone the Invading Species Hotline at: 1-800-563-7711. Originally published in the April 2018 issue of Ontario Out of Doors Click here for more outdoors news Watch on-demand videos anytime on OFAH Stream