Oak Wilt Symptoms in Texas — What to Look For (With Descriptions)

**Live oaks: the veinal browning pattern.** The single most reliable early sign of oak wilt on a live oak is a distinctive leaf pattern called veinal necrosis. The veins of the leaf turn yellow, then brown, while the tissue between the veins stays green at first. As the disease progresses, the tips and edges of the leaves brown out while the base near the stem stays green. Look for this on multiple leaves across the canopy — not just one branch, which usually means physical damage. Live oaks with oak wilt typically lose 30–50% of their canopy within a few months and continue declining over 6 months to 2 years.

**Red oaks (Spanish, blackjack, shumard): rapid canopy collapse.** Red oaks show different symptoms. Leaves turn from green to a dull bronze or pale green, then brown, often within a single week. The tree may hold onto its dead leaves rather than dropping them cleanly. The deadliest sign on a red oak is a fungal mat — a pressure pad that forms under the bark, cracks it open, and smells like fermented fruit. If you see cracked bark with what looks like a gray or tan pad underneath, that tree needs to come down before the spores spread.

**What oak wilt is NOT.** Drought stress causes uniform browning from the tips inward, usually late in summer, and typically affects the whole canopy at once rather than starting in patches. Hypoxylon canker causes bark to slough off in sheets revealing a black or gray fungal mat, but the leaves usually die on individual limbs first, not in the veinal pattern. Iron chlorosis (common on Austin's alkaline soils) causes yellow leaves with green veins — the *opposite* pattern of oak wilt. Anthracnose causes irregular brown blotches, usually after a wet spring, and rarely kills the tree.

**When to call.** If you see the veinal browning pattern on a live oak, or rapid canopy browning on a red oak, don't wait. Take clear photos of several affected leaves and the whole tree, and reach out for a diagnosis the same week. Fungal mats on red oaks are an emergency — the tree should be removed and the wood chipped or hauled before the mat matures and releases spores. For live oaks caught early, propiconazole macro-infusion has a 60–70% success rate at halting the disease.

If you're unsure whether what you're seeing is oak wilt or something more benign, sending a few photos to a local crew for a free field look is the fastest way to get a real answer instead of guessing.