Oak wilt (Ceratocystis fagacearum) is an incurable fungal tree disease which is fatal to many varieties of oaks indigenous to Austin and Central Texas, including live oak and red oak. Since 1988 more than 130 oak wilt centers have been detected in Travis County, including areas of Lost Creek!

The disease spreads through two methods:

1. transfer via hosts, most notably sap-feeding beetles, and
2. transfer via interconnected oak roots

Oak wilt is quick and devistating to many species of oak. The modus operandi of an oak wilt infestation occurs when the disease is introduced via the beetle to an uninfected tree, then quickly spreads to adjacent trees through a shared root system. Roots of oak trees -- on occasion even different species -- tend to join, connect, and fuse to each other. This behavior enhances the strength of oak trees to weather-related elements, but provides a quick and easy method of disease transferrence.

What Can I do?

First, you should protect your oaks from infestation via host transfer. When pruning, seal all wounds immediately -- within one minute -- of exposing sap wood. Beetles are more active at certain times of the year. If possible, prune oaks when beetles are not as active. Pruning sealant is still recommended regardless of season. Encourage your neighbors to do likewise.

Second, you need to be able to quickly identify the presence of oak wilt. Even if oak wilt first appears on a neighbor's tree, the infestation can quickly spread to all your oak trees. The earlier oak wilt is identified, the sooner post-infestation measures can be taken. Visit the links below to familiarize yourself with the tell-tale signs of oak wilt.

What if oak wilt appears in my back yard?

Treatment of oak wilt is costly and requires cooperation from many neighbors. Folks who treat oak wilt assume that all oaks that are not separated by a street or other underground barrier are connected via shared roots. Once one tree is infested, left untreated, all other connected oak trees will perish. The most popular method to stop the spread via shared roots is trenching. By digging deep trenches between trees, shared root systems are severed. Backfilling these trenches immediately prevents spread via host transfer.

Knowing which trees are infected is an inexact science. Most often, trees adjacent to the infected tree will be sacrificed to ensure the survival of trees beyond. Trenching is expensive and disruptive to landscapes, fences, walkways and other yard features. It requires the cooperation and financial input from all neighbors involved. The good news is that trenching is highly effective in preventing the spread of oak wilt.

If caught early, oak trees can be treated with a systemic fungicide. The most popular brand name being Alamo®. Fungicide treatment is best performed by oak wilt professionals who must inject the fungicide into tree veins. This treament does not cure the tree of oak wilt, and must be repeated every two years or so. Fungicide can also be used as a preventive measure against oak wilt.

Removal of diseased trees is of utmost importance. The goal is to provide no opportunity for the formation of fungal mats on a diseased tree.

When replanting, white oaks (white oak, burr oak, overcup oak) are recommended replacement selections because of their resistence to oak wilt. Consult an arborist, a master gardener, or a County Extension Agent for advice on replanting after oak wilt.