Trees and shrubs are often vulnerable to disease and infection. Left untreated, some of these conditions can kill or seriously damage your foliage, so it's important to make sure you understand how to deal with the risks the trees on your property face. In some parts of the United States, hypoxylon canker is a serious condition that you may find on many species of tree. Learn more about the causes and symptoms of hypoxylon canker, and what property owners need to do to prevent this condition.
What is hypoxylon canker?
Hypoxylon canker is a common fungal infection that attacks several species of North American tree. The fungi that cause this disease are opportunistic because they don't infect healthy trees. As such, you will only find the symptoms of hypoxylon canker on weakened or dying trees.
The disease affects several species of hardwood and oak trees. According to the Missouri Botanical Garden, black oaks are more susceptible than white oaks. As such, you're more likely to find this problem in red, black, scarlet and willow oak trees. In some cases, you may also find the fungus living as a saphrophyte, which means it can grow on dead wood. Common affected species include basswood, beech, hickory and sycamore trees.
How the disease affects trees
Hypoxylon canker often affects trees that are susceptible to environmental stress. An infection will occur when spores from the fungus come into contact with stressed or injured tree tissue, normally during the late summer or fall. Rain, wind, insects and rodents often spread these spores, allowing the fungus to develop on bark and wood tissue.
The signs of hypoxylon canker are relatively easy to spot. You may notice the following symptoms:
- Leaves may initially turn yellow and wilt
- Patches of bark may peel away, to expose a silvery layer of fungus with scattered black spots
- You may see sunken, depressed areas all over the bark of the tree
- Tree limbs may die entirely
Areas of fungal infection can vary from a few inches to several feet in length.
Dealing with the disease on limbs and branches
The parasite that causes hypoxylon canker is relatively weak, and a healthy tree will normally defend itself against infection. Weak or dead limbs may quickly show the signs of infection, but the disease will not normally spread to other, healthy parts of the tree. The tree will often shed any dead limbs, but you can also ask an arborist to cut away and remove these unwanted branches.
Dealing with the disease on the main trunk of the tree
Unfortunately, if a tree is showing signs of hypoxylon canker on the main trunk, it is unlikely that the tree will survive. The trunk is the tree's main transport system for moisture and nutrients, so a fungal infection indicates that this system is beyond repair. What's more, if more than 15 percent of the crown shows the infection, experts recommend that you cut the tree to ground level and burn it.
The fungus can remain active in dead wood, so you shouldn't chip the debris and use it for mulch. That aside, the disease does not spread from tree to tree. The fungus often lives in the outer bark of trees, without causing any problems. Only trees that are already dying will suffer an infection.
Preventing hypoxylon canker infection
Homeowners and gardeners can take several measures to avoid a hypoxylon canker infection. Regular and ongoing deep root fertilization can protect a tree's health. Prune back weak, dying or dead limbs, and get rid of the unwanted wood as quickly as possible. It's also important to avoid injury to the trunks and limbs of your trees. A fungal infection becomes more likely as soon as your trees suffer any stress.
It's worth consulting an arborist before making changes that may affect shade trees. Mature trees are less resilient, so even minor changes to the landscape or irrigation can cause problems. You should also try not to interfere with the soil in a tree's root zone. Soil changes can break down the bark tissue, increasing the risk of infection.
Hypoxylon canker is a common fungal infection that affects a range of trees across the United States. Once an infection sets in, you cannot cure your trees of this disease, but you can work with your arborist to prevent any serious problems occurring. To learn more, be sure to visit http://www.completelandscaping.com.