Oak wilt (Bretziella fagacearum)
The most destructive tree disease in Texas. Kills red oaks within months once symptoms appear; live oaks decline over 1-3 years and spread via interconnected root systems. Vector: sap-feeding beetles (Nitidulidae) attracted to fresh wounds during the February-June window. Treatment: propiconazole macro-infusion every 24 months for preventive treatment, annual for confirmed cases. Confirmed-infected red oaks should be removed and the wood treated. Trenching to sever root grafts is essential to stop neighborhood spread in live oak motts. Never prune oaks February through June without immediate wound sealing.
Bacterial leaf scorch (Xylella fastidiosa)
A slow killer of mature DFW oaks and elms. Bacteria colonize the xylem, restricting water flow. Symptoms: marginal leaf browning with a thin yellow halo, worst in late August through October, progressing each year. Treatment: annual oxytetracycline trunk injection, starting at first symptoms — the earlier the better. BLS is not curable, but treatment can extend functional life by 5-15+ years. Lab PCR test recommended for definitive diagnosis before starting treatment.
Iron chlorosis (micronutrient deficiency)
Not technically a disease but the most common tree-health complaint in DFW. Caused by our alkaline clay soils chemically locking up iron and manganese. Symptoms: yellow leaves with green veins, often starting on south-facing parts of the canopy. Most affected species: Shumard red oaks, sweetgums, pin oaks, magnolias. Treatment: trunk injection of chelated iron + manganese every 1-3 years depending on severity. Visible greening within 4-8 weeks.
Anthracnose (Apiognomonia spp., other foliar fungi)
Most common on sycamores and oaks in cool, wet springs. Symptoms: irregular brown blotches on leaves, sometimes following leaf veins, early leaf drop in severe cases. Treatment: typically not warranted (cosmetic and self-limiting). For high-value trees, fungicide application at bud break in spring may reduce next-year severity. Sanitation of fallen leaves helps.
Hypoxylon canker (Biscogniauxia atropunctata)
The opportunistic pathogen that finishes off drought-stressed and construction-stressed oaks in DFW. Symptoms: bark sloughing in patches revealing gray-black fungal mats, sudden canopy dieback. No effective treatment once established. Focus: stress reduction on neighboring trees to prevent next year's losses.
Phytophthora root rot (Phytophthora cinnamomi)
Soil-borne pathogen affecting roots, especially in poorly-drained or overwatered sites. Symptoms: gradual canopy decline, root system dieback visible if excavated. Treatment: phosphite root drench, soil drainage correction, mulching. Often requires soil moisture management changes (correct sprinkler over-watering, improve drainage).
Free diagnostic visit before any treatment
Treatment selection depends on accurate diagnosis. We don't treat a tree without first confirming what's wrong. Initial visit is always free; we'll tell you whether treatment is warranted.