Oak Wilt: What To Look Out For!

Be on the lookout for oak wilt! Oak wilt is a fungal disease that rapidly kills oak trees, and is active in Kent County. The first case of oak wilt in Grand Rapids in over 10 years was just confirmed in Cambridge Park when our City Forester was assessing another tree. This case was detected very early and the city’s forestry crew was able to act immediately to stop the spread. This involves removing the infected tree (and burying the infected wood for over a year to kill the spores), trenching around the area, and treating the oaks inside the trenched area. The disease can spread through the roots to other nearby oaks if not properly trenched. 

The city’s forestry department will continue to monitor the area and is optimistic that the spread has stopped. However, it’s a good idea for neighbors to monitor their trees, especially ones on private property. 

Things to look for in your oak trees:

  • Sudden browning of leaves—looks like a coffee stain that moves through the leaf
  • An orange fungus inside the bark (often said to smell like Juicy Fruit gum)
Photo by Monique Sakalidis, MSU.

This disease can be extremely hard to determine since the most obvious symptoms are similar to the effects of drought stress, which many of our trees are showing this year. 

How you can prevent oak wilt:

  • Do not move firewood or sticks between counties
  • Do not prune oak trees from April until October (be sure you know what trees you have—some oaks have oval leaves!)
  • If your oak tree sustains damage during the No-Pruning months, prune the damaged limb and apply latex paint immediately (the only time paint should be applied to a cut on a tree)

If you think you have oak wilt, contact a certified arborist immediately so they can diagnose quickly! There is no cure for the infected tree, but by acting quickly, you can save surrounding trees. We are thankful for the city’s team for acting so quickly to save our urban forest!