Dutch Elm Disease
Ophiostoma ulmi
Dutch Elm Disease
Dutch Elm Disease is a rampant killer of elm trees and one of the most dangerous diseases to trees in the world. By using elm bark beetles, it infects the tree deep inside the wood and multiplies inside the trees vascular system. This stops the flow of nutrients and water to the leaves and instead sends up toxins that cause the leaves to shrivel and drop. In most cases, by the time a tree is showing any symptoms of the disease, it is already too late and that the fungus has taken over the tree. The fungus can also pass from infected tree to a healthy tree via the root systems if they are connected.
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Identification
Yellowing and browning of the leaves in early summer. Followed by rapid branch and often tree death. In some rare cases, the tree will survive until the next year where it will then die. Dark brown streaks may be visible in the wood if the bark is peeled back a little.
Growth factors
If the tree is weakened or in poor growing conditions then it is more likely to get attacked by the elm bark beetle and so more likely to get the disease.
Symptoms
Leaf curling in early summer
Leaf drop.
Dark brown streaks under bark
Biological treatment
There are no treatments
Chemical treatment
There are no treatments
Lifecycle
The beetles burrow and lay their eggs in the bark of dead wood where the fungus is growing. Once the beetles are adults they emerge from the bark covered in spores. The new adults find a healthy tree and burrow into the bark. The spores rub off into the healthy wood and block the conducting tissues causing it to wilt and die.
Prevention
Growing resistant varieties. Not growing a large group of elm trees next to each other.
Affected plants
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