Dufferin County residents are urged not to prune, harvest or otherwise damage oak trees from April 1 to July 31 to help prevent the spread of oak wilt.
Oak wilt is a vascular disease of oak trees, caused by a fungus that can kill trees within weeks after infection. The disease is spread by sap beetles, through grafted tree roots, and through movement of infected firewood. Fresh wounds on trees can attract the beetles that are one of the culprits responsible for spreading the disease.
Oak wilt has not yet been found in Ontario — but experts are concerned because it has spread across Michigan and is on Belle Isle in the Detroit River between Detroit and Windsor.
All oak species are at risk from this disease. The red oak group (red, black, pin) is the most susceptible; oaks in the white oak group (white, bur) are also affected but are more resistant. Once infected, the trees can die within a matter of weeks, with foliage on the trees turning from yellow to red to brown in mid-summer.
“To prepare for the arrival of oak wilt, we have already placed restrictions on the harvesting of oak in the County Forest,” reported Caroline Mach, R.P.F., County Forest Manager.
Follow these steps to prevent the spread of oak wilt:
1. Do not prune oak trees April 1 through July 31. If you must, apply a coat of pruning paint to the cut surface immediately;
2. Do not move firewood;
3. Report suspected occurrences of oak wilt to EDDMapS Ontario www.eddmaps.org/ontario and the Invading Species Hotline 1-800-563-7711.
For more information, go to forestinvasives.ca/Meet-the-Species/Pathogens/Oak-Wilt.