Hypoxylon Canker Explained: Causes, Symptoms, and Prevention
Hypoxylon canker is a fungal disease that has been responsible for the death of many trees in East Texas in recent years. While this disease isn’t rare, it has become more prevalent in the last few years due to droughts that cause stress to trees –which leads to an increased risk of infection.
Since there is no known cure for hypoxylon canker, it is important to learn about the disease to help prevent your trees from becoming infected.
What is Hypoxylon canker?
Hypoxylon canker is a fungal disease that attacks weakened, stressed, or damaged trees. Damages caused by defoliation due to insects, drought, or nutrient deficiencies also increase the risk of infection. Hypoxylon canker ultimately produces cankers, which cause the death of the tree, in oak and many other hardwood trees.
This fungus is often present in many healthy trees and is found in the inner bark, it is only once it invades the sapwood that the disease presents a threat to a tree.
Since it is difficult for the fungus to grow where the moisture content is normal, hypoxylon canker usually attacks when a drought has been present. Drought also causes trees to become stressed. When a tree is stressed, the fungus is more likely to takes advantage of the weakened tree.
How is it Detected?
Hypoxylon canker is usually first noticed when the foliage starts to turn yellow, eventually drying out. This dieback will continue from one branch to the other, until the disease eventually reaches the trunk, and the tree dies. Depending on the environment and the stress on the tree, a tree can last for one year or more before it is eventually destroyed by the hypoxylon canker.
The fungus that causes hypoxylon canker is known to be present in many healthy trees, without causing damage. Trees can be healthy and survive for long periods of time without any problems. This is because it doesn’t infect the tree until it is weakened. When a tree is weakened, or stressed – the fungus will then invade the sapwood, eventually contributing to the death of the tree.
Tips for Prevention
There is no known cure for hypoxylon canker. The best defense against it is prevention: try to keep your trees free from stress, and healthy. Removing infected trees is pointless – because the fungus is already present in most trees in the inner bark – and isn’t spread through the air. A stressed or weakened tree allows a passage for the fungus to invade the sapwood, and infect the inside of a tree.
During drought, it’s important to supplement your trees with water. Avoid injury to the truck and limbs, and avoid filling in the bottom of the tree with fill soil, as this can increase the chances of hypoxylon canker.