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What Diseases Affect Tree Bark

If you notice something odd about your trees, the culprit may be a bark disease. The signs of this type of disease will usually be sparse foliage, dead branches, and unsightly marks, patches, or sores. Just because your tree has a bark disease, however, doesn’t mean that the tree is beyond saving. But before you know how to deal with the tree bark disease, you have to know how to identify it. Read on below to find out more about what tree bark diseases to look out for.

Canker Diseases

Canker diseases are caused when a fungal or bacterial pathogen enters the tree. The tree’s vascular system gets blocked, making it hard to get the necessary water and nutrients. This will lead to individual branches dying.

Trees that are already stressed or damaged are especially vulnerable to tree bark diseases. The fungal or bacterial pathogen will usually enter through a wound. This can be due to the environment it’s in or an injury to the tree. To avoid this damage in the first place, make sure trees are planted in areas that will be suitable and give the trees the growing conditions they need.

Thousand Cankers Disease

This category covers a variety of tree bark diseases. For instance, this includes thousand cankers disease. As you may have guessed from the name, one of the signs and symptoms of this disease is the appearance of many small cankers. There may be an amber stain surrounding the cankers. In some cases, the bark also appears cracked. The disease is caused by bark beetles creating the space beneath the bark that enables fungus to enter. In some cases, a tree may have already been infested for some time before any symptoms start to become noticeable.

Cytospora Canker Disease

There’s also Cytospora canker disease, which appears on pine, poplar, spruce, and willow trees. It’s caused by fungi that particularly attack stressed trees. It’s especially bad for trees that already have root damage. Trees that experienced drought, frost, sunscald, or some kind of injury are also more likely to get the disease. Proper watering can help prevent this disease. Another prevention measure is to prune only during dry weather, as that’s when trees are better able to defend against fungi.

The first symptoms of Cytospora canker disease are usually browning needles and dying branches. The most common symptom is usually rapidly dying bark. In some cases, the affected bark may not noticeably change color, as with other tree bark diseases. If you remove the first thin outer layer of bark, you’ll see that the inner bark has changed color, usually turning black. The bark can also split around the canker. The exact appearance of the bark will vary depending on the tree. On spruce trees, for instance, you may notice patches of resin on the bark that is white, amber, or purplish white. On aspens, you’ll see small black bumps.

Bleeding Canker

Meanwhile, a bleeding canker affects maple trees and makes the bark appear wet. It causes reddish oozing, hence the name. The dead wood under the canker will also appear red. Bleeding canker signs can also include bark coming away from the lower tree trunk.

Dutch Elm Disease

Dutch elm disease is an invasive fungal infection that affects American elm trees and other elm species. It can be caused by elm bark beetles, which eat away healthy tree sap. Insecticides may be able to keep these beetles away.

This tree bark disease really affects the tree’s vascular system, clogging the vascular tissue, which makes it difficult for the crown of the tree to get enough water. That causes the crown to wilt. It affects individual branches and will cause leaves to turn yellow and curl up. This is typically the first sign of infection. Later, the leaves will turn brown and fall off. If nothing is done about this disease for some time, it can kill the whole tree.

Beech Bark Disease

This tree bark disease is an infection that appears reddish-brown and like a wound. It’s caused by a combination of the European beech scale insects’ feeding habits and at least two different species of Nectria fungus. The infection will make the foliage look sparse and yellow, and the crown will look much thinner. Beech bark disease also weakens the tree, making it much more susceptible to other types of tree diseases.

Black Knot

This tree bark fungal disease causes ugly black swellings to appear. The swellings won’t turn black until later, about a year or so after the tree first gets infected. When they first appear, they’re green or greenish-brown. It’s typically found on fruit tree bark, such as cherry, plum, or apricot trees. This isn’t just an ugly or unsightly growth. It can also cause the tree to die if not taken care of. Regular pruning, especially when the trees are dormant, can help to keep this fungus away. If you’re doing the pruning yourself, make sure your equipment is properly cleaned and disinfected every time you use it.

Black Rot

This is a tree bark disease that affects hardwood fruit trees, particularly plum and apple trees. It gets into the tree via wounds that allow the fungus to enter. These wounds can be caused by insects, irregular pruning, or damage that occurs naturally. At first, the bark will start to appear reddish-brown. If left untreated, the bark will turn black and shrink, which also causes the bark to peel back. The infection can weaken trees significantly.

If you think your tree has one of these bark diseases but aren’t sure or want an expert option, contact us at Mr. Tree. Our service experts will always have the best insight on how to take care of your trees. If your tree does need to be cut down, for instance, that’s a job that should be left to professionals. At Mr. Tree, we have the experience and expertise to handle any tree problem. You can find more information on our website.