Gardening 101: Worried About Oak Wilt?

Oak wilt is fatal for all the species in the red oak group; those oaks with pointy-tipped leaves

Video Transcript

JEFF RAY: In today's Gardening 101, Oak trees are as much part of the Texas landscape as pickup trucks and cattle. But an incurable disease is spreading through the Oak tree population. And it could threaten the Oak tree in your yard.

Oak trees, if you don't have one in your yard, there's a good bet there's one on your street. But there has been a major problem with Oak trees slowly brewing.

RACHEL MCGREGOR: So the first case was in 1961 in Dallas County.

For the last 60 years, Oak Wilt has crept across North Texas and the Hill country. Currently, it is found in 37 counties, including most of our area.

RACHEL MCGREGOR: It's a vascular fungus. And it blocks up the outer part of the tree so nutrients and water can't flow up and down the tree.

JEFF RAY: It can kill a Red Oak and four to six weeks. It can kill a Live Oak and a couple of months as it spreads from tree to tree.

RACHEL MCGREGOR: They're all growing out of one massive root system. And that fungus just continues to travel through all those interconnected roots underground that we can't see.

JEFF RAY: It also spreads by a type of beetle that feeds off the exposed fungus. Any Oak tree can get it. Some species, like Red and Live Oaks, are more susceptible. You can spot Oak Wilt by the leaves of the trees starting to die off.

RACHEL MCGREGOR: So that's yellowing or reddening of the main veins in the leaf. So it's very distinctive once you know what the pattern looks like.

JEFF RAY: If you catch it early, a fungicide injected around the base of the tree can slow the disease. But there is no cure. Prevention is the best hope.

RACHEL MCGREGOR: February 1 to the end of June, don't prune your Oak trees. None of your Oak trees. Other trees, you're fine. But February 1 to the end of June, don't prune your Oak trees. And all other times of the year, always paint those wounds or pruning cuts on those Oak trees.

JEFF RAY: Any outdoor latex paint will do that seals away the fungus from the beetle that can spread it. The best answer to Oak Wilt, currently, is all of us teaming up together and doing the right thing.

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