Oak Wilt

Oak Wilt Risk Status

Oak wilt is an aggressive disease that affects oak trees. It is one of the most serious tree diseases in the eastern United States. Caused by the fungi Ceratocystis fagacearum, oak wilt primarily attacks red and pin oaks and to a lesser extent white and burr oaks.


Symptoms of oak wilt first appear in red oaks as rapid wilting and browning of leaves from the leaf tip to the leaf base typically in the upper canopy. The wilting and subsequent leaf drop rapidly progresses throughout the canopy and within 2 to 6 weeks tree death occurs. Infected white oaks die slowly, a branch at a time, often surviving for many years. Leaf discoloration of affected white oaks resembles autumn colors.

The fungus invades the conductive system of the tree, preventing the water and nutrients from reaching the leaves, which results in wilting and eventual death.

How does is spread?

  • Insects, most common is the picnic or sap beetle. This beetle feeds on the sap of recently wounded oaks and if it feeds on an infected oak, it will transmit the disease to a healthy oak.
  • The second method of transmission is through grafted roots. The root systems of oak that are in close proximity to one another tend to fuse together. If one oak becomes infected, the disease can move rapidly within the grafted roots to a healthy tree.

Treatment Options:

  • Trunk injections can help prevent healthy oaks trees from contracting oak wilt. These treatments are most successful in controlling the spread to high valued oaks when used as a preventative treatment on oaks that are not root grafted.
  • Cutting or severing the root system by a professional can effectively isolate infected trees and help prevent the spread of oak wilt through a root graft transmission.
  • Removal of infected, dead oak trees will also help to prevent the fungal mats that spread the disease to healthy oaks.

Things you can do:

  • If you suspsect oak wilt, call an ISA Certified Aborist® to do an inspection of your oak trees.
  • Do not prune your oaks in the spring and summer months. Timing varies from year to year, so consult your ISA Certified Arborist® on when it is safe to prune your oaks.
  • Do not store firewood from oak wilt infected oaks, unles the bark has been removed and properly disposed of.


If you suspect oak wilt in your trees, contact us today at 651-451-8907 or fill out the form below.



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