Managing Verticillium Wilt in Trees

Verticillium wilt is a fungal disease that can attack a variety of landscape trees, including both smaller trees, like lilacs and dogwoods, and larger trees, like oaks and maples. The disease often results in the death of the tree. Understanding the disease and how to prevent it can help you save your trees. The following guide can help.

How does verticillium wilt spread?

The fungus that causes the wilt lives within the soil. It invades the tree via the roots and then spreads through the tree's vascular system until the entire tree is infected.

Is there are a cure for verticillium wilt?

There is no cure for this disease. Standard fungicides will not affect the fungus once it has invaded the vascular system of the tree. If the verticillium fungus is found in the soil, there are effective fumigation treatments that can kill the fungus so that future plantings won't be affected.

What are the symptoms of verticillium wilt?

Symptoms can vary, depending on the age, health, and variety of tree, but the following are relatively common in most trees:

  • Foliage that appears scorched and begins to die off fairly quickly for no known reason. Younger or smaller trees often have dieback in large clumps, while larger trees may only have a branch or two that initially suffers from foliage dieback.

  • Elongated sections of dead bark may begin to appear on the trunk. The bark may begin to peel off or there may be a wound visible that is weeping sap.

  • Visible streaks in cut wood. This is most readily noticed when pruning. When looking at the cut end of the branch, you may see gray, green, or black streaking in the wood grain.

Can the fungus be controlled?

There is no hope for the tree once it has been infected. The best control is to have a tree service contractor remove the tree and it's roots promptly. This can help prevent the fungus from spreading to other nearby trees. Even if the tree still seems relatively healthy, the falling leaves from the tree will contain the fungus, thus spreading it back into the soil.

How can future plantings be protected?

Fumigating the soil is an option, although it is best suited for small areas. Watering frequently can also help, since the fungus cannot survive in wet soil without a host plant. You should also commit to only planting species that are naturally resistant to verticillium wilt, such as apple, walnut, or willow trees.

For more help, contact a professional like Arborcare Tree Service in your area.