AUSTIN, Texas — The big, beautiful live oaks that line your street and shade your home aren’t indefensible. There’s a silent killer that at this very moment could be creeping down your block, one yard at a time.

Considered an epidemic throughout Central Texas, oak wilt is one of the most destructive tree diseases in the United States. The infectious disease spreads in the spring, killing all trees that share its name, with red oaks and live oaks most susceptible.

“A live oak is a great survivor against everything that gets thrown at it from wind damage to drought to insects and other diseases, but it’s a poor survivor with oak wilt,” said Texas A&M Forest Service Regional Forest Health Coordinator Jim Houser in Austin.

Oak mortality has been noted since the 1930s, but oak wilt wasn’t confirmed as the cause until the late 1970s. It has since been found in 76 counties — principally in Central Texas though it’s crept as far as Amarillo and Houston.

An infected oak can spread the disease to surrounding oaks via their interconnected root systems. When that happens, the only way to stop further spread is by digging trenches to break the root connections.

Oak wilt also can be spread from February through June via sap-feeding beetles, which eat spore mats produced by infected red oaks. The disease is spread when those insects fly off to feed on a healthy red oak or live oak with a fresh wound.

Diseased live oaks do not produce the same spores but they can become infected by them.

“We’re talking about trees that have been in the landscape for a century or more. We don’t replace those trees overnight,” Houser said, adding that the death of such majestic trees can lead to drops in property values. “Preventing oak wilt is the key.”

A wound is created any time bark is removed and wood is exposed. That can happen with the simplest of tasks — planting flowers, pruning or even pushing a lawn mower over a bare tree root.

That bare wood produces sap, which attracts the sap-feeding beetles, Houser said, stressing the importance of avoiding wounds in the spring, painting tree wounds year round and destroying diseased red oaks that may harbor spore mats on which sap-feeding beetles may feed and spread the disease.

“You don’t want to have to manage oak wilt. That means you have it. You want to prevent it from happening,” said Houser, explaining that there was no cure for the disease. “An ounce of prevention is worth it to avoid starting oak wilt disease and killing your trees.”

For more information about oak wilt and maps detailing which counties are affected, visit www.texasoakwilt.org, Texas A&M Forest Service www.tfsweb.tamu.edu have a tree tested for oak wilt through  the Texas A&M Plant Disease Diagnostic Clinic & Laboratory at www.plantclinic.tamu.edu. You may also contact your local municipal forester.

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Photos of Oak Wilt and its symptoms available at https://www.flickr.com/photos/texasforestservice/albums/72157693997774934

Contact
Jim Houser, Regional Forest Health Coordinator in Austin
512-339-4589, jhouser@tfs.tamu.edu

Communications Office in College Station
979-458-6606 office, newsmedia@tfs.tamu.edu