Some problems that develop with trees compromise their beauty by causing bumps on leaves, yellowing of leaves or some leaves to fall off. These issues are usually the result of certain insects or mites that don’t tend to seriously harm trees. In contrast, if you have a tree with signs of oak wilt, fast action is important.

Tree service technicians can inject a specific fungicide into healthy oak trees on your land to prevent transmission of the deadly fungus. Unfortunately, injecting the sick tree may not be enough to save it. 

About Oak Wilt

Oak wilt is caused by a fungus known as Ceratocystis fagacearum. Some oak species are resistant to the fungus, while red oak is particularly vulnerable, according to the Natural Resources Conservation Service (NRCS). Live oak infections are especially problematic because the root systems of these trees readily spread the fungus to other live oaks.

The infection spreads when tree roots contact one another and graft together. It also may spread when fungus grows under the bark, attracting beetles. Those insects transmit the spores to other trees. In addition, a person who trims a tree without realizing it’s infected and then trims another tree can spread the fungus that way. 

Oak Wilt Symptoms

Symptoms of this fungal infection are somewhat variant in different oak species. Signs include:

  • entire leaves or the leaf veins turning tan, yellow or brown in parts of the canopy
  • leaves — even the fully green ones — falling off in large numbers
  • fungus mats under the bark causing cracking and unpleasant odors
  • beetles feeding on sap where the bark has cracked

Oak Wilt Treatment & Prevention

Eradicating this fungus in an infected tree is difficult. If you tackle the problem quickly, you may be able to stop the fungus from spreading to other oaks. It’s best to have tree service technicians do the work, as the process is complex and you want to know that it’s done right.

The technicians uncover roots around the base of healthy oak trees and inject a fungicide called propiconazole, as explained by the NRCS. This has a strong preventive effect against Ceratocystis fagacearum. However, sometimes the preventive measure doesn’t work because the tree already has the fungus but hasn’t yet shown symptoms.

Depending on the species of your tree that is affected by oak wilt, the technicians may attempt to save it. The tree injections don’t seem to be effective at killing the fungus in red oaks, but they may work in other oak species.

If any trees cannot be saved, you should have them removed so they don’t infect other oaks.