Oak Wilt is a horrible tree disease that plagues Central Texas. I wanted to relay some Austin-specific information to help Austinites navigate the Oak Wilt Pandemic.
I do not want to reinvent the wheel, so I will link to websites and interviews that go over the basic information around Oak Wilt down below. I thought it would be interesting and helpful to write an article specifically about Oak Wilt in Austin. My team and I have 25 years combined of diagnosing and treating Oak Wilt in Austin, and these are the most important things we have found for protecting your trees from this horrible disease.
Oak Wilt Basic Information – https://texasoakwilt.org/ This website will teach you a massive amount about the disease and how to detect it and options for treating.
https://www.youtube.com/watch?v=H_DW9gsPQCs This is a great interview by the Central Texas Gardener with a Central Texas Board Certified Master Arborist about Oak Wilt in Central Texas.
Where is Oak Wilt in Austin?
The City of Austin put together a heat map that will help you figure out if Oak Wilt is in your area. https://www.arcgis.com/apps/Minimalist/index.html?appid=77bd761640454639992165ca91a9a0c5
This map is extremely useful but is not perfect. Sometimes you have to zoom in and out to get it to show the heatmap, and sometimes the heatmap just fades entirely, but if you play with it enough you will see if there are spots to be concerned about in your area. It also does not relay the severity of the disease in an area. For example, there is just a small blip in Shady hollow, but we know that Oak Wilt has ravaged sections of Shady Hollow and is a significant threat there. It also completely excludes Steiner Ranch, which has been suffering a major Oak Wilt outbreak over the past 10 years.
I don’t see Oak Wilt in my neighborhood on the map, what should I do to prevent my neighborhood from getting Oak Wilt?
If there is no Oak Wilt near you, the main thing you need to do is NOT prune your trees between February 1st and July 1st. Pruning wounds can attract the nitidulid beetle, which is responsible for long distance transmission of the disease. Oak Wilt is like a fire, with these beetles being arsonists. Once the beetle infects your tree through a pruning wound, the disease will spread like a fire into the whole neighborhood through the tree’s root system.
I live in an Oak Wilt hot spot; how do I know if my tree has Oak Wilt?
While Red Oaks and other oaks are susceptible and do get Oak Wilt, the main victims are the Live Oaks due to how they are connected underground via their roots.
The best indicators that your home or neighborhood may have Oak Wilt are:
– Leaves start falling off of Live Oaks starting at the top and working its way down
– A wave of dead and dying Live Oak trees moving through the neighborhood
– Symptomatic leaves on the trees or on the ground (See the photos for what they look like)
You can also call an arborist and have them assess the Oak Wilt threat to your trees. I will many times launch my drone and inspect the surrounding area for Oak Wilt outbreaks that threaten my client’s trees.
What should I do to protect my trees?
The main way to protect your trees from Oak Wilt in an urban environment like Austin is with preventative injection of a fungicide. These injections provide about 95% protection to uninfected trees for 2 years. The effectiveness on already infected trees is very low, but can work if the disease is detected early enough. Trenching and other management techniques are rarely viable in a dense urban setting.
When should I Inject my Trees to protect against Oak Wilt?
The furthest I have seen Oak Wilt spread underground in one year is 150 feet. I recommend preventatively injecting all Live Oak trees that you want to protect within 150 feet of any infected tree.
We get the best results when we perform the injections in Late April and May, but the injections can be conducted most of the year.
I think my tree is infected, what should I do?
Call an arborist or three to inspect the tree and make recommendations. Arborists will typically give free consultations and estimates, so it is good to get three opinions to make sure the information is consistent and that you are receiving fair pricing.
Infected trees can be saved by injections as long as the infection is detected early enough. If you live in an Oak Wilt hot spot, it is crucial to be vigilant and monitor your Live Oaks.
My property has Oak Wilt, what do I do?
Have an arborist or 3 thoroughly assess the property and come up with a plan. Ideally you want to inject the Live Oak trees that you want to keep and remove the low value trees and the trees that are too far gone with infection. Herbicide the stumps of the infected trees to prevent the root systems from harboring the disease. Oak Wilt injections are not simple or easy, but they are also not rocket surgery. You can DIY Oak Wilt Injections with some investment and time.
TLDR:
Here’s a cool map that can help you figure out if you need to be worried about Oak Wilt in Austin, https://www.arcgis.com/apps/Minimalist/index.htmlappid=77bd761640454639992165ca91a9a0c5
Author: Andrew Anstrom
Board Certified Master Arborist
