About this Tree Concern
Dutch elm disease is an invasive fungus that was first confirmed in Ontario in 1946. Since then there have been two species of this fungus confirmed and this diseases has become widespread in the elm populations of Ontario.
The fungus is spread mainly by two species of beetles: European elm bark beetle and the native elm bark beetle. The disease can also spread through root grafts from infected trees to healthy trees.
The beetles dig galleries beneath the bark of infected trees where they reproduce; in spring, the bark beetles which have become covered by fungal spores, emerge and attach to healthy trees and begin feeding. The fungus develops in the sap-conducting tissues under the bark and causes wilting and browning of the foliage.
Infections usually are fatal and the tree dies within one to three years.
Remediation
Once detected, there is little remediation opportunity for the infected tree, however, early detection and removal could prevent adjacent elm trees from also becoming infected.