Expanding yellow or brown patches can suggest large patch, but appearance alone does not confirm a fungal disease. Check the leaf symptoms, lawn conditions, and recent maintenance history before deciding what to treat.
What does large patch affect?
UF/IFAS describes large patch as a disease associated with Rhizoctonia solani. Warm-season turfgrasses can be affected, especially St. Augustinegrass and zoysiagrass. Cool, wet conditions favor disease activity. UF/IFAS large patch reference
Leaf bases can become soft and dark, and affected leaves may separate easily from the stem. Roots are not the part attacked by this pathogen. These are assessment clues rather than a stand-alone home test: UF/IFAS also notes that herbicide injury can resemble the symptoms.
What should you document?
Use the lawn observation worksheet to record the grass type if known, date first noticed, shape, location, and whether the patch is changing. Take an overview photo and a close-up at the edge of affected grass.
Record irrigation run times, recent rainfall, standing water, mowing changes, and the names and dates of recent products. Keep the details even when you are unsure which ones matter; that uncertainty is useful to the person assessing the lawn.
What other explanations should be considered?
Uneven irrigation, insect activity, and recent chemical or mechanical injury can change lawn appearance. Compare the chinch bug guide if insects are present. Finding an insect does not automatically establish that it caused the patch.
Do not use a circular shape or a loose leaf as the sole reason to apply a fungicide. Ask which findings support the diagnosis and whether an in-person inspection or sample is needed.
Turn a photograph into an assessment record
A close-up may show a leaf symptom but give no indication of how the area relates to the rest of the lawn. An overview may show a circular pattern while hiding the condition of individual leaves. Keep both, with the date and a short location description.
Add a separate note for recent maintenance or product use. If you do not know the product name, say so and ask whoever performed the work for the service record. Do not guess a material or application date to fill the blank.
A useful assessment can then distinguish what was observed, what explanation is supported, and what remains uncertain. If more than one area is affected, ask whether the same explanation fits each location. This avoids turning a single photograph into a diagnosis for the whole property.
Common questions
What should a lawn recommendation explain?
A useful recommendation identifies the likely cause, remaining uncertainty, and the maintenance or treatment steps that follow from the evidence. Ask how irrigation and site conditions will be considered alongside any proposed application.
The lawn estimate page provides a starting point for service options. For an uncertain diagnosis, describe your observations and request an assessment instead of selecting a treatment solely from a photograph.
How can you track the outcome?
Repeat photos from the same position and record changes in the patch boundary and new growth. Keep the dates of any work performed. Ask what signs would warrant follow-up and which changes can be evaluated at the next assessment; avoid assuming an exact recovery deadline.
