How to identify and manage oak wilt in Texas
Measures can be taken to break root connections between live oaks or dense groups of red oaks to reduce or stop root transmission of the oak wilt fungus. The most common technique is to sever roots by trenching at least 4 ft deep with trenching machines, rock saws, or ripper bars. Trenches more than 4 ft deep may be needed to assure control in deeper soils. Although not required, commercially-available root barriers may be inserted in the trench to reduce the potential for trench breakouts. Correct placement of the trench is critical for successful protection of uninfected trees. There is a delay between colonization of the root systemby the fungus and appearance of symptoms in the crown. Therefore, all trees with symptoms should be carefully identified first. Then, the trench should be placed a minimum of 100 ft beyond these symptomatic trees, even though there may be “healthy” trees at high risk of infection inside the trench. Trees within the 100-ft barrier, including those without symptoms, may be uprooted or cut down and removed to improve the barrier to root transmission. Tree removal should be initiated after trenching, starting with healthy trees adjacent to the trench and gradually working inward to include symptomatic trees.