Elm trees are known for their straight, powerful trunks and their multi-branch crowns. When healthy, they can grow impressively tall and give you decades of shade and comfort. However, not all elm trees are healthy. Some eventually come down with a disease. Two of the most serious and deadly elm tree diseases are Dutch elm disease and phloem necrosis. Here is some advice for dealing with each of these deadly conditions.
Dutch Elm Disease
Dutch elm disease is a serious fungal disease caused by a pathogen called Ophiostoma novo-ulmi. It can be spread from tree to tree by elm bark beetles. The beetles carry the fungal spores on their bodies and introduce them to the elm tree while feeding on its bark.
The first sign of Dutch elm disease is yellowing on one or a few branches. Then, as the season draws on, more and more branches will turn yellow. If you peel back a little of the tree's bark, you may see black-brown streaks on the exposed wood.
Sadly, there is no cure for Dutch elm disease. Tree care experts usually recommend having infected trees removed. The sooner you do this, the better. You want to have the tree removed before the fungi make its wood too spongy and brittle. Removing it sooner also causes the elm bark beetles to disperse and hopefully spread the fungi to fewer neighboring trees.
Phloem necrosis is an elm disease caused by tiny parasites known as phytoplasmas. They invade the phloem of the tree, which is the tissue that's meant to carry nutrients throughout the tree. As the phloem becomes infected and dies, the elm tree starts to turn yellow. This happens suddenly. Some people report that they woke up one day and noticed their whole elm tree was yellow. For this reason, phloem necrosis is sometimes called elm yellows.
Elm yellows kill trees quickly, and it also spreads very rapidly from tree to tree. It is thought to be transmitted by leaf-hopping insects. The best way to reduce its spread is to have infected elm trees removed ASAP. You or your tree care company will want to burn the wood to kill any leaf hoppers and phytoplasmas that are present.
If your elm tree starts showing symptoms of either of these diseases, don't delay in contacting a tree care company. You can't often save trees that are infected with these diseases, but you can have the infected trees removed to protect other elms nearby.
Reach out to a local company that offers tree removal services to learn more.Share
7 July 2023
Elm, ash, walnut, maple, apple — these are all gorgeous trees, but they all have their own preferences in terms of care. Maple trees, for example, need to be pruned later in the season once their sap has begun flowing. Elm trees should be pruned in winter when insects aren't around in order to protect them from the emerald ash borer. A good tree care company will treat each of your trees as individuals, customizing care to their own specific needs. Still, it's important that you, as the tree owner, understand those needs, too. Read the articles on your website, and you'll soon have a pretty good grasps on the basics of tree care.