Dutch Elm Disease - Facts

Dutch Elm disease has affected over 80% of trees in the capital city of Ontario. Because this is such a prominent issue, we at Eagle Tree and Landscaping Service here in North Bay want to give you the lowdown on a tall subject. Here are some Dutch Elm disease facts you'll want to keep in mind. As always if you have any questions, feel free to contact us today at 705-472-1818 for professional advice, or a free quote on our landscaping services.

What is Dutch Elm Disease?
When a beautiful Elm tree seems to die for no apparent reason in the middle of the summer, most likely its a sign of Dutch Elm Disease (DED). Dutch researcher Bea Shwarz identified Dutch Elm Disease as resulting from fungi. There are two types of Dutch Elm Disease fungus- Ophiostoma ulmi and Ophiostoma novo-ulmi .


How Does Dutch Elm Disease Spread?
The Dutch Elm Disease life cycle begins when one of three species of beetle- the native Elm bark beetle Hylurgopinus rufipes, the smaller European Elm beetle Scolytus multistriatus, or the Banded Elm bark beetle Scolytus schevyrewi deposit their eggs under the bark of dead or dying trees where Dutch Elm Disease is already present. As the larvae grow and consume the bark, spores populate the pathways, called galleries, left behind. When the beetle emerges it is saturated with spores that it then takes to other Elms after chewing a hole through the outer bark. According to Minnesota State Extension Service “Once in the trees' vascular system, the fungal spores move up the tree with the flow of water or produce a thread-like growth called mycelium that grows downward towards the root system. In susceptible trees, the fungus is often capable of reaching the root system within the first season and can spread to adjoining elm trees through grafted root systems.” Because the tree can be inseminated with the fungi at several points from multiple beetles the infection can spread quite rapidly.


Where Does Dutch Elm Disease Come From?
Though the fungus was identified in 1921, it is believed that it originated in Asia, where the trees were found have become resistant to the fungus. The spread of the disease exploded when transported to Europe around 1910, where the carnage claimed millions of trees and more than 25 million in Britain in as little as three decades. Spreading to the United States in 1931 from a shipment of logs from France, Dutch Elm Disease spread like wildfire, claiming hundreds of thousands of non-resistant trees. 1946 saw the first confirmed case of Dutch Elm Disease in Ontario, and by the early 1980s, over 80% of the trees in Toronto alone had fallen victim.


How Do I Get A Dutch Elm Disease Diagnosis?
The best way to get a definite diagnosis is from a professional arborist at Eagle Tree and Landscaping in North Bay, Ontario. Here are some general indicators of the disease to look for:


Dutch Elm Disease Symptoms:
The first signs of illness are quite apparent in Dutch Elm Disease before and after the new leaves of spring come on, but are unmistakable by the middle of June. Dutch Elm Disease leaves take on the characteristic yellowing and wilted look called flagging. Beginning at the tips of the branches and progressing toward the center of the tree, leaves will yellow and curl, drying into a darker brown and very brittle. Patches in the crown of the tree will loose their leaves and litter the ground below in an un-seasonable manner. The following spring will find the leaves stunted, if they are able to develop at all, and are soon withered from lack of venous circulation. Brown or purplish discolorations are noticeable on the outer sapwood ( the layer under the hard outer bark) If the outer layer of bark is dead removing a portion will reveal the tunnels or galleries of the beetle larvae. The two smaller of the beetle species, European Elm bark beetle, and the Banded Elm bark beetle will feed in the crotch of the smaller limbs and branches, allowing the fungus to be introduced into the trees vascular system.


Does Dutch Elm Disease Kill Trees?
Looking at history we can see the gruesome Dutch Elm Disease damage our forests have been through. Millions of casualties can attest to the gravity of the disease. Thankfully, not all elm trees fall prey to Dutch Elm Disease, and with proper treatment by a qualified arborist from a professional tree company, there may yet be hope.


Which Elm Species Are Most At Risk?
Because Dutch Elm Disease is an invasive species, by definition there are no natural immunities found in the Elm trees native to the North American continent. American Elm(Ulmus Americana), Rock Elm (Ulmus Thomasii), Red Elm (Ulmus Rubra) and Slippery Elm (Ulmus Fulva) are the fungus's prime targets.


Dutch Elm Disease-Resistant Varieties
There are several varieties that have been developed in controlled environments that combine the qualities of the Elm's Asian cousins that have a natural resistance to the disease. Although they are still able to contract the condition, the tree has the ability to block the spread of the pathogen and thus limit the extent of the damage. These trees will still need proper limb pruning to remove affected branches.


Is there a Dutch Elm Disease Cure?
In the early 80s Canadians decided to divert from the traditional method of aggressive spraying of the Elm damaging beetles to attacking the fungus. By injecting enough fungicide into the trees venous systems any spores carried by beetles would be unable to propagate continuance of the Dutch Elm Disease life cycle.  Combining these methods with quick tree trimming and Dutch Elm Disease tree disposal techniques used by landscaping services, Dutch Elm Disease control has not only been a possibility but a success. With equally aggressive measures native Elm populations can be stabilized and even see population growth.


How Is Dutch Elm Disease Prevented?
No truer is the phrase “ an ounce of prevention is worth a pound of cure,” than in the case of Dutch Elm Disease treatment. In most cases where a tree does not have a high value (as would one in a city, or around a public building) the most cost-effective way to prevent the spread is to trim extensively. In the event of a dense population of Elms proper prevention could mandate tree disposal.


Dutch Elm Disease Removal and Disposal
Even though it's sad to see some of these giants succumb to the ravages of Dutch Elm Disease, we at Eagle Tree and Landscaping are a professionally certified to provide tree removal services, stump grinding or complete stump removal as the case may be.
Because Dutch Elm Diseased trees aren't fit for firewood, our landscaping services in North Bay can properly process and re-purpose the Dutch Elm Diseased wood chips. Because the disease can no longer spread in this form we practice responsible stewardship with our natural resources to extend their beauty even after their death.


Replacing Dutch Elm Diseased Trees
If you're just starting the process, or just finishing up with Dutch Elm Disease tree removal, consider letting us help you plan for the future with our tree planting services. We'll go over the options and help you decide on the best choices to fit your landscaping style and tastes.


We welcome any questions or concerns you may have on the topic of Dutch Elm Disease in Ontario and encourage you to get in touch with us today for a free estimate on landscaping, tree trimming, limb pruning, stump grinding or stump removal, even interlock deck building! As well we are more than happy to provide the best tree care services in the North Bay area. Call today at  705-472-1818.

Hal (owner of Eagle Tree Service) asked by the Nugget for a comment on Dutch Elm Disease.
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