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Beech Bark Disease
Nectina coccinea var, faginata

Butternut Canker
Ophiognomonia clavigignenti-juglandacearum

Dutch Elm Disease

Oak Wilt

Sudden Oak Death

Thousand Cankers Disease


Pathogens¬†Forest pathogens have been on the rise given the increase in international trade and exchange of plant material. Pathogens that kill trees, such as butternut canker that attacks butternut trees, are a big threat to Ontario’s forests, putting native species at risk.

Forest pathogens can be caused by different organisms that affect the whole tree, causing defoliation, root decay and stem cankers that reduce the distribution of nutrients throughout the tree.

You can help to prevent the spread of forest pathogens.

  • Learn to identify signs and symptoms of forest pathogens that are a threat to Ontario
  • Don’t move firewood. Burn it where you buy it
  • Don’t move infested wood material to new areas
  • Contact your local Ministry of Natural Resources office for more information if you believe you have an infected tree on your property before you consider cutting it down
  • Report all sightings to the Invading Species Hotline 1-800-563-7711 or report a sighting online