As a tree owner, your worst nightmare might go a little something like this:
You walk out into your garden. It’s the first thing in the morning, on the first day of spring. You look up into the boughs of your gorgeous elm tree, ready to take a deep breath of fresh, spring air.
And then you see it: the upper branches of your once majestic elm have begun to wither and turn yellow.
What could it be? As it turns out, one of the most damaging elm diseases in the United States.
Join us, today, as we take a closer look at Dutch Elm Disease, its effects, signs, and how to manage it.
Dutch Elm Disease (or DED) is a fungal infection that attacks and damages elm trees mainly in Minnesota, but in Florida and Texas too (to a lesser degree).
Brought about by the sac fungi (or Ascomycota), DED is spread by bark beetles. These are native to many elm trees and have devastated large swathes of elm trees in the past. It affects all native elm species. There are some species, mostly Asiatic and Russian variants, that are more resistant to the disease. These may be more likely to survive an infection, but any elm tree is susceptible to DED.
Dutch Elm Disease was first identified in 1921 by two Dutch phytopathologists, Bea Schwarz and Christine Busiman. It’s an insidious condition, in that it essentially tricks the tree into killing itself. The disease makes its initial infection, and the elm tree responds by using gum and tyloses to plug up its own xylem tissue. If you’re not sure what that means, it’s like when police in a high-speed chase set up a roadblock on a highway to head a criminal off before he can get any further.
The problem is that roadblock also keeps the police from going any further, meaning the city beyond doesn’t get the police protection it needs. Only, with a tree, it’s not police protection – it’s nutrients.
Look for upper branches in the summer months where the leaves are starting to wither and become yellow, before their time. This discoloration will eventually spread to the rest of the tree.
In the late stages of the disease, the roots die from lack of nutrients.
As devastating as Dutch Elm Disease can be in any garden, there are steps you can take to help mitigate the negative effects and save your tree.
Cultural: one approach to DED management is to avoid monocultures in your yard. Remove dead branches and leaves, as well as excess cut wood. Burn or chip removed wood and leaves to protect against it forming a home for beetles.
Chemical: insecticides are a viable option for treating DED, but not in the standard delivery. The more effective way to use these is to inject them into the tree itself and to use them as a preventative measure instead of as a response to an infection. Even with these, chemicals are certainly not the most effective treatment option out there.
Breeding: Disease-resistant elm trees have been bred in response to the spread of DED, and are one of the best long-term solutions to this disease. Cross breeding European and US trees with Asian elms has improved native trees’ ability to withstand a Dutch Elm infection.
Dutch Elm Disease, left unchecked, can be a devastating condition in any elm-friendly yard. Even in Florida, where the disease is less prevalent, you still need to be prepared.
Interested in expert yard and tree services? Get in touch with us, today, or check out some of our other great blogs, and start taking your yard back.