On November 12, 2001 Robert Edmonson of the Texas Forest Service, Johnson City office, made a one hour presentation to the Tierra Linda Garden Club. Robert has a degree in Forestry from Texas Tech and has been helping residents in Tierra Linda since 1993. Robert can be contacted in his office at 1-830-868-7949.
The following is essentially a transcript of Robert Edmonson’s presentation, including the questions asked by our homeowners. (11/04 This article has been reviewed and is still current in content.) OAK WILT Oak wilt is caused by a fungus. Oak wilt affects both urban and rural areas.
How do you recognize and diagnose oak wilt? Live Oaks:In live oaks, the symptoms are veinal necrosis (dead veins) which has a yellow fish-skeletal appearance on the elliptical green leaf, or the reverse, with a green fish skeletal appearance on a yellow leaf. These leaves fall from the tree. There can also be oak wilt cases where the end of the leaf dies or where the margin of the leaf dies. These latter symptoms could also be due to other causes, such as salt damage, herbicide damage, or freeze damage. Veinal necrosis on live oak leaves is however very diagnostic of oak wilt. A healthy tree can suddenly begin dropping leaves, and dropping more leaves, until the leaf canopy becomes very thin. Eventually the entire canopy is gone. This process can take as little as 3 to 6 months from initial infection to death.