Hypoxylon Canker in Oaks: Part 1
April 2, 2013
Did you know that trees under stress are much more likely to fall victim to pests and diseases? Just like in people, a suppressed immune system leaves your trees open to infection or infestation. Just like in people, prevention is always preferred to treatment. Getting your trees healthy and vigorous is the best way to fend off health problem.
Today we’d like to introduce you to a disease that is becoming a bigger problem for our oak trees here in North Texas: Hypoxylon Canker. That’s a mouthful, we know! So we’ll be posting a series of short articles about this disease to cover its biology, stress factors, identification and treatment options.
Hypoxylon Canker is caused by a fungus called Biscogniauxia (Hypoxylon) atropunctatum. This fungus only attacks trees under stress, not healthy trees. Specifically, this fungus can infect any kind of oak tree. The canker appears as dead lesions on bark, limbs and branches of infected trees. These cankers develop under the bark as a black rot that eventually causes a white rot decay of the tree’s sapwood. This disease not only causes tree death, but it makes the tree structurally unsound; meaning it becomes a hazard tree that can be dangerous to your home and family.You may have read about the 100 year old red oak, infected with Hypoxylon canker, that we had to remove from Swiss Avenue.
Construction damage is one of the biggest stress factors that contribute to a tree succumbing to Hypoxylon canker. Construction of new homes, swimming pools, sidewalks, patios and more cause wounds to tree roots and damage the overall root system. This damage impairs the tree’s ability to take up water and nutrients. Soil compaction from heavy equipment or construction materials stored around the tree can suffocate roots. These conditions cause the tree to decline and become susceptible to the Hypoxylon Canker disease. Heat, drought, ice storms, hail damage, lightning, and flooding can also contribute to tree stress. Combine our extended drought with construction damage and you may have a lethal combination.
Next in the series we’ll talk more about signs and symptoms of the disease. In the meantime, if you have a construction project coming up please read more about how we can properly protect your trees.