The first observation: leaf color & pattern
Leaf symptoms are the most visible clue and they're highly diagnostic if you know the patterns. Yellow leaves with green veins (interveinal chlorosis): iron or manganese deficiency, almost always caused by alkaline DFW soil locking up these micronutrients. Marginal leaf browning with a yellow halo: bacterial leaf scorch (BLS), a vector-transmitted bacterial disease. Sudden mid-season wilting and bronzing on a single branch: oak wilt in red oaks, a fungal disease that can kill the tree within months. Diffuse uniform yellowing: often nitrogen deficiency or root issues. Spotted or blotched leaves: typically anthracnose or another foliar fungus.
The second observation: distribution
Where are the symptoms? Whole canopy uniformly affected suggests root or trunk problems (compaction, girdling, herbicide damage, root rot). Localized to specific branches suggests vascular pathogens (oak wilt) or branch-specific issues. Worst on the south or west side suggests drought stress. Worst on the north side suggests excess moisture or root rot. Starting at the top and working down suggests vascular blockage. Starting at the bottom and working up suggests root or trunk damage.
Trunk and bark inspection
We sound the trunk with a rubber mallet at 6-inch intervals — hollow tones indicate internal decay. We examine the bark for cracks, cankers, fruiting bodies (mushrooms or conks suggest active fungal decay), insect frass, exit holes, and oozing. We check the root flare exposure — a buried root flare is a slow killer and one of the most common diagnoses on younger Seagoville trees. We look for girdling roots that wrap around the trunk and strangle vascular tissue.
Soil & site evaluation
We probe the soil under the dripline to check compaction (the probe should slide in easily for 6+ inches if soil is healthy) and moisture. We look at recent landscape changes — grade changes, irrigation adjustments, herbicide applications, or new construction within the root zone. Many "sick tree" calls in Seagoville trace to something that happened months or years earlier (the house renovation, the new patio, the redirected drainage).
Lab confirmation when needed
For ambiguous cases or where the diagnosis must be definitive (oak wilt vs BLS, for example — they look similar but need different treatments), we submit samples to the Texas Plant Disease Diagnostic Laboratory at Texas A&M. Standard turnaround is 5–10 business days. We use lab work as the standard for oak wilt confirmation, bacterial pathogens, and any unfamiliar fungal disease.
What we recommend after diagnosis
Once we have a confirmed diagnosis, we present 1–3 options with honest trade-offs: the best-case scenario, a moderate-cost approach, and (sometimes) the decision to remove and replace if the tree is too far gone. About 30% of our sick-tree visits in Seagoville end with us telling the homeowner the issue is non-fatal and the tree will recover on its own. That's not the answer that maximizes our revenue — it's the answer that earns trust and referrals.
Free diagnostic visit in Seagoville
Every sick-tree call gets a free initial visit and verbal diagnosis. Written treatment plans are included. Lab work, when needed, is billed separately at lab cost ($35–$150 per sample). Call (817) 670-4404 to schedule.