Tree Health & Oak Wilt Management

Oak wilt is a lethal vascular disease caused by the fungus Bretziella fagacearum. It spreads two ways in Central Texas: underground through the interconnected root systems that link neighbouring live oaks, and above ground by sap-feeding nitidulid beetles that carry spores from fungal mats on dead red oaks to fresh wounds on healthy trees. Roughly 90% of local spread is through roots.

Avoid pruning oaks from February through June, the period when sap-feeding beetles are most active and most strongly attracted to fresh wounds. July through January is the safer window. If storm damage forces an emergency cut during spring, paint every wound immediately, within minutes rather than hours.

Sometimes, depending on species and stage. Live oaks showing early symptoms can respond to propiconazole injection, and some survive with reduced crowns. Red oaks rarely survive once symptoms appear and generally die within weeks to months. Injection is most valuable as protection for healthy high-value trees near a known infection centre, rather than as a rescue for a tree already in steep decline.

Three things, usually together. Macro-infusion injection puts propiconazole into the vascular system through the root flare, dosed on trunk diameter, and needs repeating roughly every 18 to 24 months while pressure continues. Trenching cuts a line four feet deep to sever the grafted roots carrying the fungus toward healthy trees. Infected red oak material is removed and disposed of properly so it cannot produce fungal mats. We map all three onto your property in a written plan after inspection.

Be careful with it. Red oak that died of oak wilt can produce spore-bearing fungal mats under the bark, and stacking that wood next to healthy trees is a genuine way to start a new infection centre. Do not move unseasoned red oak firewood between properties. If you already have some, keep it fully covered with clear plastic sealed at the ground until it is thoroughly seasoned.