Oak wilt is quickly spreading and killing some of the areas oldest oak trees

KBN recently met with Karen Rockoff, owner of Rockoff Tree Solutions. She is also a local Certified Arborist with the International Society of Arboriculture and a Master Certified Landscaper with Texas Nursery Landscape Association. She aims to share her knowledge about a deadly tree fungal disease called “Oak wilt,” which is being spread rapidly through the area. Rockoff also wants the public to be aware of how to treat and prevent the disease.


Oakwilt is a fungal disease affecting oak trees. Signs and symptoms vary but generally consist of leaf discoloration, browning, wilt, defoliation, and death.

Once a tree is infected with Oak wilt it normally kills a tree. In the Hill Country, Rockoff has found Oak wilt in Live Oaks and Red Oaks. She also tells KBN that she has found the fungal condition in Post Oaks and Lacy Oaks, which is very rare, but she has been finding it in Kerr and Medina County.

The disease can spread quickly from tree to tree in a couple of different ways.

Photo courtesy of Rebekah Strickland

One way Oak wilt is spread is through beetles. When a tree branch breaks, it emits a pheromone which attracts beetles. The beetle then comes to eat the sap from the tree, in turn, the beetle gets the disease on their bodies and carries it to the next tree they feed on.

Another way Oak wilt makes its way around town is through the root grafts. For example, at Louise Hays Park, the roots are grafted together so when one tree gets infected, it is only a matter of time before the trees surrounding it catch the disease.

Tree cutters are spreading it, too. Rockoff says, “We’ve had some cases around Kerrville where if the tree hasn’t been pruned properly or sprayed to kill that pheromone smell to the beetle,  they will get infected. This has happened at River Hills Mall. We diagnosed the tree last year, a few months after it was cut. When it was cut, it was the wrong time of year and they didn’t spray the wounds. Now it seems the root grafting is happening fast. Smaller trees are now showing some very early signs indicating oak wilt. Not all the trees are showing signs at the mall yet. They are not all in decline but they have been infected. ”

Photo courtesy of Rebekah Strickland

Also, residents around town are contributing to the spread by not practicing safety when cutting down oak trees on their property. If someone cuts down an oak tree, Rockoff explains, that it is important to chip, shred or burn the tree right away.

The residents are moving their firewood from neighbor to neighbor, as well as taking firewood out of the county. Residents need to cover their firewood and keep it on their property, says Rockoff.

“I am trying to get the word out there for people to be careful with their practices and just make sure they are aware of Oak wilt. Don’t hire anyone that doesn’t know about this disease or how to maintain their equipment or how to control (the disease),” Rockoff states.

Over the past 10 years, Karen has been monitoring several trees around town and has noticed a great decline in the health of the area’s tree.

Karen Rockoff says “we diagnosed (the trees at Louise Hays Park) with Oak wilt last year and we have just been watching the trees going into decline. They aren’t getting a lot of rain this time of year and they are declining even faster. We’re losing a lot of big mature trees, over 200 years old, to Oak wilt, all over town”

Currently, at Louise Hays Park, residents can notice the trees that are infected. Rockoff diagnosed these trees last year. The trees that are infected have lost total canopy. A tree on the property pointed out by Rockoff had a full canopy last year but was in decline, yellowing. The tree still had a lot of leaves. Right now, the tree only has a few limbs and is dying fast.

Photo courtesy of Rebekah Strickland

Voicing her concerns, Rockoff tells KBN, “It’s sitting in a public park with all that decay. Limbs can drop at any moment and hurt or kill somebody. Those trees need to be removed right away.”

“I want people to learn about Oak wilt and how to recognize it and how to care for their trees and realize it’s taking over the Hill Country. If they’re not aware we’re not going to have a lot of oaks left. The larger oaks, very mature oaks, seem to be dying at a fast rate”

She also wants property owners to be aware that they can buy a product called ChemJet, which is used to treat the disease. Rockoff tells us, “It’s not expensive and it’s not as scary as it used to be. We do it a new way that allows the property owner to take their trees back and maintain them. Most of these people think that Oak wilt can’t be treated or trees can’t be saved or it’s too expensive. That’s not true anymore.”

Rockoff continues to say, “ChemJet is a reloadable, reusable tree injection system that homeowners can do themselves. I think is really cool because I think we can save a lot more trees this way. However, if a property owner hires a company or contractor to use ChemJet on their oaks, this person needs to be licensed and insured in the state of Texas”

In conclusion, residents are advised to prune and cut their oaks during the correct time of year and to dispose of cut trees properly. If a homeowner suspects a tree of having Oak wilt, call a professional tree cutter immediately. If a tree on your property isn’t infected, it is recommended to care for the tree correctly to help prevent the tree from getting the disease.

Kerrville is full of old, beautiful trees and, as residents of the community, it is our responsibility to care for them properly.

For more information about Oak wilt, visit www.oakwilt.com or to gain more information about ChemJet, visit www.chemjet.com