SAN ANTONIO – In South Central Texas, oak trees aren’t just trees: they’re infrastructure, history and climate protection.
Between February and June, those trees face an increased risk from oak wilt, a fast-moving disease that can spread quickly and kill entire clusters of oaks. The disease that impacts oak trees across much of the region.
According to the Texas A&M Forest Service, the disease has been reported in more than 75 counties, with heavy impacts in the Hill Country.
Oak wilt cases have been identified in parts of Bexar County, including Helotes, Leon Valley, Shavano Park, Hollywood Park and Castle Hills.
How oak wilt impacts trees
“Oak wilt is a very devastating disease in Central Texas,” said Demian Gomez with the Texas A&M Forest Service. “It’s fungus that infects every single oak tree that it encounters.”
All oak species are affected, but some are more vulnerable than others:
Red oaks have nearly a 100% mortality rateLive oaks often die, especially when the disease spreads undergroundWhite oaks may be less susceptible but can become infectedHow oak wilt spreadsVia connected root systems, where nearby oak trees share underground connectionsVia sap beetles, which carry fungal spores from infected trees to healthy ones
These beetles are attracted to fresh wounds on oak trees, especially during spring and early summer.
“When you prune, that wound is going to release chemicals that basically attract these beetles,” Gomez said.
Experts recommend not pruning oak trees between February and June, when beetle activity and fungal spread are at their highest.
What to look for in infected treesBrown or dark veins on live oak leavesTip burn where the ends of leaves turn brownFungal mats under the bark in severe cases, especially in red oaks
Due to other issues such as drought or herbicide exposure can cause similar symptoms, experts said proper identification is important before taking action.
What to do if you suspect oak wilt
If pruning is unavoidable for safety reasons, experts recommend painting the wound immediately.
“Any type of paint or pruning seal works,” Gomez said. “It creates a barrier that keeps insects from introducing the fungus.”
Homeowners who suspect oak wilt are encouraged to visit texasoakwilt.org where they can connect with a local forester to help confirm the disease and discuss next steps.
How to manage oak wiltRemove infected red oaks to prevent fungal mat formationTrenching to break underground root connections and stop the disease from spreadingFungicide injections to protect salvageable treesHelp paying for treatment
Treating oak wilt can be costly, but federal cost-share funding is available to qualifying landowners.
The Oak Wilt Suppression ProjectHomeowners may receive up to $2,000 for red oak removalUp to $5,000 or 50% of costs for trenching
Experts said protecting oak trees isn’t just about the environment — it’s also about economics.
Losing mature oak trees can significantly impact property values and sometimes cost homeowners thousands of dollars.
By taking preventative steps now, experts said Central Texans can help protect their trees, their neighborhoods and the landscape that defines the region.
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