You notice black leaves on one tree and peeling bark on another. Should either come down? Not on that information alone. Before buying a treatment or booking removal, find out what has changed and whether the tree itself is being harmed.
You can bring those concerns to the Northwest Houston team's plant-health services. If you're reading about common tree diseases in Northwest Houston, start with the differences below. Texas A&M's guidance explains why oak wilt, hypoxylon canker, sooty mold, and ball moss call for very different responses.
Oak Wilt
Oak wilt is caused by the fungus Bretziella fagacearum, which invades a tree's water-conducting tissue. Texas A&M Forest Service's February 2025 oak-wilt guidance describes veinal necrosis in live oaks: discoloration associated with the leaf veins. A leaf symptom can prompt investigation, but it does not confirm oak wilt by itself.
Which kind of oak is it? That matters. Red oaks are the most susceptible, live oaks fall between red and white oaks, and white oaks are less susceptible but not immune. Sap-feeding beetles can carry the fungus to wounds above ground, and connected roots can carry it between trees underground.
Texas A&M Forest Service recommends avoiding pruning or wounding oak trees from February through June, a high-risk period for spread. Fresh oak wounds should be painted immediately in any season, not just during that window. Leave dangerous branch work to properly qualified professionals rather than climbing to make a cut or reach a wound.
After a diagnosis, an oak-wilt specialist can explain whether root-graft barriers or fungicide treatment would help. Ask which trees an action would protect and what it cannot do. Treatment of an individual tree and management of underground spread are different parts of the problem.
Hypoxylon Canker
With hypoxylon canker, the distinction is between a fungus being present and actively damaging the tree. Texas A&M Forest Service's hypoxylon guidance explains that Biscogniauxia atropunctatum can live in the inner bark of a healthy tree without invading its sapwood. Drought, root injury, or another stress can allow it to become active and decay that wood.
Watch for a thinning crown, dying branches, and bark coming away from the trunk. Powdery tan or brown fungal material exposed beneath the bark can darken and later look silver-gray. Report what you see from a safe position, but don't use surface color to judge how much sound wood is left.
There is no known cure for hypoxylon canker. Protecting roots and maintaining vigor can help healthy trees withstand stress, but that is prevention, not a treatment that reverses active disease. An affected tree needs an evaluation of its condition and stability, including whether removal is necessary.
Don't climb a tree with suspected hypoxylon damage for a better view. Texas A&M Forest Service warns that a tree killed by this disease may not support a climber's weight. Keep people away from damaged wood and leave the access and removal method to qualified professionals.
Sooty Mold
Sooty mold is the black coating that can make leaves and branches look dirty. According to the Texas A&M AgriLife Extension Plant Disease Handbook, its food is honeydew: sugary secretions from insects such as aphids, scales, and whiteflies. The fungus grows on that material rather than invading living plant tissue.
Look beyond the black coating to the insect producing its food. A professional can identify that insect and decide whether control is warranted. Once the honeydew source is reduced, the old coating may take time to flake off or wash away in rain, so an immediate change in appearance isn't the only measure of progress.
Ball Moss
Ball moss uses a tree as a perch, not a food source. It is a nonparasitic epiphyte, and Texas A&M AgriLife Extension's March 2026 ball-moss resource explains that it doesn't harm its host. Finding it on a branch isn't a diagnosis of tree disease.
That reassurance applies to identified ball moss, not every gray growth visible from the ground. If appearance or heavy growth bothers you, ask about those concerns separately. A dead branch still needs attention for its own condition, even when the plant sitting on it is harmless.
Why Inspection Matters More Than a Photo Search
Use a photo search to find words for what you're seeing, not to settle a diagnosis. Leaf changes and dieback have more than one possible cause. An arborist may need specialist input or laboratory confirmation, particularly for suspected oak wilt, before recommending treatment.
Before booking tree trimming in Tomball, mention unexplained leaf loss or bark changes. The crew needs to know whether the request is for ordinary clearance or an unresolved health concern. Cutting is not automatically treatment, and oak-pruning timing deserves its own discussion.
A short history helps: when did you first notice the change, and was it one branch or the whole crown? Mention recent digging or other work near the roots. Share photographs and that history before collecting samples, since the professional or laboratory should specify what it needs and how to collect it.
Whether the appointment is for tree trimming in Cypress or tree trimming in Spring, describe the concern when you call. Ask whether the proposed visit covers that question or whether a separate evaluation should come first. It is better to settle the scope before a crew arrives expecting only clearance work.
What a Confirmed Diagnosis Actually Changes
A diagnosis should change the next step. For sooty mold, the question may be whether the honeydew-producing insects need management. For active hypoxylon canker, a promise to restore the tree with chemicals would conflict with the lack of a known cure. Suspected oak wilt calls for confirmation and a site-specific discussion with someone experienced in its management.
Before agreeing to work, ask, “What finding supports this recommendation?” Then ask what improvement or follow-up the professional expects. If the decision is pruning versus removal, the existing remove-or-trim assessment guide introduces that separate question about management and risk.
Common Tree Diseases FAQs
How do I know if my oak tree has oak wilt?
You cannot confirm oak wilt from leaf appearance alone. Vein discoloration in a live oak is worth reporting, but the evaluator needs the species and site history and may recommend laboratory confirmation. Bring photos to the discussion without treating a match to an online image as the answer.
Is hypoxylon canker contagious to other trees?
Hypoxylon does not spread through groups of trees in the same way as oak wilt. Its airborne spores can colonize inner bark without harming a healthy tree, then invade sapwood when the tree is weakened. Preventing avoidable stress helps healthy trees, but it does not cure a tree with active disease.
Is the gray moss on my tree branches harmful?
If it is ball moss, the growth is nonparasitic and isn't feeding on your tree. Have it identified before drawing that conclusion from its color. Ask a separate question about any dead or damaged branches underneath it, because removing a harmless growth won't address another cause of decline.
Can a diseased tree be saved, or does it have to come down?
The diagnosis and the tree's condition determine the options. Sooty mold may call for insect management, not removal. Active hypoxylon canker has no known cure, so the next discussion is about stability and safety. Ask what a proposed treatment can realistically accomplish before deciding whether to retain the tree.
When is the highest-risk time to prune oak trees in Texas?
Texas A&M Forest Service recommends avoiding oak pruning and wounding from February through June. Plan that timing with the contractor, but keep the wound precaution on the work plan in every season: fresh oak wounds should be painted immediately. A fall appointment does not remove that precaution.
Getting an Accurate Diagnosis First
A tree doesn't need a treatment just because something on it looks unusual. It does need the right attention when bark loss, dieback, or other changes point to a real problem. Start with identification, then make the care or safety decision that the findings support.
Bring your observations to Monster Tree Service of Northwest Houston and ask which evaluation fits the concern. Confirm what the visit includes, how diagnostic work is priced, and whether specialist input would be useful before settling a work plan.