Red Oaks and Oak Wilt Disease in Texas

Date August 05, 2021

Author TreeNewal Staff

Oak Wilt disease is one of the deadliest tree diseases in North America, and it is wreaking havoc on our Texas trees, especially our Red Oak trees of Texas. Although Oak Wilt attacks all Oak trees, Red Oak trees are more susceptible and are killed faster than other Oak trees. Read on for more information about Red Oaks and the role they play in the Oak Wilt cycle.

What is Red Oak Wilt?

Oak Wilt is a vascular wilt pathogen that attacks Oak trees. It’s caused by the fungus Bretziella fagacearum, and once the fungus infects a tree, it invades and cripples the tree’s water-conducting systems, killing the tree in a matter of weeks. It most commonly affects Red Oak and Live Oak trees in our area, but it can infect any Oak tree.

Where is Oak Wilt in Texas?

You might have seen signs along the highways or articles on the internet warning property owners not to prune their Oak trees from February to June and wondered what all the fuss is about. It’s all about preventing the spread of Oak Wilt, which is devastating our Oak trees in Texas. It is in more than 76 counties and nearly every city in Central Texas, including our own neighborhoods in Dallas-Fort Worth.

What is an Oak Wilt center?

Oak Wilt can spread in two ways. One way is by Nitidulid Beetles, which are attracted to the sweet-smelling fungal spores that Oak Wilt produces under the bark of infected Red Oak trees. They spread the disease long distances by carrying the spores to open wounds on uninfected oak trees. Oak Wilt can spread through root-to-root contact, which makes nearby Oak trees especially susceptible to infection. When several Oak trees within an area have contracted Oak Wilt, that’s called an Oak Wilt center. In Oak Wilt centers, the majority of trees are lost through root spread between adjoining trees. The best way to stop the expansion of an Oak Wilt center is to dig a trench to create a buffer between the trees that are infected with Oak Wilt and healthy trees. However, that isn’t easy to do in residential areas.

Are Red Oaks more at risk of infection?

Oak Wilt can infect any Oak tree no matter its age or health, but Red Oaks are especially susceptible to infection. They never survive Oak Wilt and usually die within four to six weeks after showing symptoms. Certain Red Oaks, such as Shumard, Spanish, and Blackjack Oaks, are the most at risk. Red Oaks plays a particular role in spreading Oak Wilt because only infected Red Oaks develop Oak Wilt fungal mats. Fungal mats don’t form on Live Oaks and White Oaks. Although it’s unlikely that you’ll see these fungal mats because they grow under the bark, a certified arborist or other tree care expert knowledgeable about Oak Wilt should be able to identify the narrow cracks it makes in the bark. They can also expose the mats by cutting the bark away. The fungal mats have a distinct sweet smell that makes them more easily identifiable. Still, an official diagnosis can also be confirmed by sending a sample to a laboratory, such as the Texas Plant Disease Diagnostic Lab.

What are the signs of Oak Wilt?

Once the fungus reaches the vascular tissue, the tree tries to protect itself from the further spread by plugging cells and causing branches to wilt. This will likely be when you first notice the signs of Oak Wilt in late spring or early summer. It’s important to note that the leaf symptoms on Red Oak trees can look very similar to other possible ailments or diseases. At the same time, leaf symptoms on Live Oaks are more distinct to Oak Wilt. In both types, you’ll notice yellowing and then browning leaves at the top of your trees. The individual leaves will begin to brown at the margin toward the end of the leaf and then progress down the margin to the stem. As the leaves brown, they will fall from the tree and litter the ground. Because other Oak tree diseases cause similar symptoms, the best thing you can do if you notice any of these signs is contact a certified arborist as soon as possible to assess your tree.

How can we prevent the spread of Oak Wilt?

As far as Red Oak Wilt treatment goes, there’s unfortunately little to nothing that can be done to save your Red Oaks once they’ve contracted Oak Wilt. The best method is Red Oak Wilt prevention. Knowing when to prune Red Oak Trees is one of the most important things you can do to avoid the spread of Texas Red Oak Wilt during Red Oak Wilt season. Whenever possible, you should avoid pruning Red Oak trees from February through June in North Texas because this is when fungal mats are actively producing spores, and it’s also when the sap-feeding beetles are most active. Plant sap that forms on the surface of cuts and wounds attracts sap-feeding beetles. While they’re feeding, the spores attach to the beetles’ bodies, which they then carry to healthy trees. By not trimming Red Oak trees during this time, you can help prevent attracting these beetles to your trees. The second thing you can do to prevent the spread of Oak Wilt is to contact a certified arborist as soon as possible if you think Oak Wilt has attacked your Oak tree. A professional tree care company like TreeNewal can remove and dispose of your trees quickly and carefully to prevent further spread to nearby trees.

TreeNewal can help with all your Red Oak tree needs.

If you have questions about pruning your Red Oak trees or think your tree might be sick or dying from Oak Wilt, work with a professional tree care company like TreeNewal with ISA Certified Arborists with official Oak Wilt Qualifications. These qualifications mean our arborists have specialized training in identifying, preventing and treating Oak Wilt disease. TreeNewal is a certified arborist tree service with the tools and knowledge to perform the safe branch and tree removal techniques, including disposing of diseased materials and performing other preventative measures to stop further spread of Oak Wilt. TreeNewal offers a full range of expert tree care services, including safe Red Oak tree trimming and pruning, expert management for various pests and diseases, and professional tree removal. Our Dallas-Fort Worth tree doctors care deeply about protecting your trees from diseases, pests, fungus, and any other ailments. For more information about our tree care services, go to our website at To set up an appointment, call us at tel:(817) 592-6846.

To learn more about Red Oaks and Oak Wilt Disease in Texas, TX, call our Argyle and Southlake-based teams

at tel:(817) 592-6846 or send us a message.

We’re a little different than the average tree services company.

Learn more about TreeNewal’s ISA Certified Arborists!

Our Dallas/Fort Worth-based tree doctors can explain how sustainable tree care services add more value to your bottom line.

Healthy trees, healthy lives.