There’s an opportunistic fungus lurking, just waiting for the right moment to devour your trees.
From oaks, elms and pecan to hickory, sycamore and even yaupon holly, hypoxylon canker is already present in many healthy trees. But when a tree’s health deteriorates, the fungus can strike.
Conditions that can compromise the long-term health of trees include:
- Compacted soils.
- Root damage.
- Improper planting or pruning.
- Inadequate water (either too much or too little).
- Drastic changes in temperature.
In addition, trees can be affected by competition with other plants (including grass and other trees) for resources such as water, nutrients and sun.
In recent years hypoxylon canker has spread in Texas trees severely weakened by extreme cold, heat and drought. The first symptoms often include yellowing leaves or smaller-than-normal leaves.
Over time, the canopy foliage begins to thin and to compensate for the lack of foliage, a tree may develop epicormic shoots, or “water sprouts,” visible throughout the stem and branches. Eventually branches die and bark begins to fall off. That’s when canker itself may become visible underneath: white, gristly sapwood that begins to lose structural integrity.
In the end, the masses of exposed fungus blacken as if the tree has been burnt. The best recommendation for badly affected trees is to remove them to avoid spreading spores of infection to other trees.
Unfortunately, there is no cure for hypoxylon canker, but in some cases, if less than 15% of the canopy is affected, it may be possible to remove dead branches to prevent further spread. If you are concerned about this and other tree diseases, contact a licensed arborist.
The best recommendation, as always, is to provide your trees with the best conditions to make them strong, so they don’t fall victim to this and other opportunistic diseases.
