Brown Patch in Bermudagrass: Symptoms, Management, and Control

Brown patch (Rhizoctonia solani) is a common summer disease of bermudagrass, especially under high nitrogen, warm nights (>68°F), and hot days (>80°F).

Symptoms

• Small circular dead patches that enlarge and merge (>3 ft).
• "Doughnut" pattern: tan ring with green center.
• Individual blades brown to the crown; crown remains green.
• White fungal web at patch edge on humid mornings.

Cultural Management (First Line of Defense)

• Fertilize moderately in summer—only enough for color.
• Water deeply (5–7 inches) only when soil is dry; irrigate 10 PM–10 AM.
• Avoid evening watering; wet leaves 14+ hours fuel the fungus.

Fungicide Options

Chlorothalonil (Daconil), Bayleton (Fung-Away), or myclobutanil (Immunox) can suppress the disease. Apply every 14 days. Cost: ~$20/1,000 sq ft per application ($100/5,000 sq ft every two weeks). Cultural changes are cheaper and longer-lasting.

Expert Q&A

Q: Can I put something in the soil to eliminate brown patch?

A: No. Spores are ubiquitous. Outbreaks occur when grass is stressed (drought, over-fert, over-water). Control the environment: deep weekly watering, no fertilizer after May.

Q: Big yellow spots expanding daily—is it brown patch?

A: Could be. Confirm "doughnut" pattern and green crowns. Rule out soggy spots, compaction, fuel spills. Change irrigation to one deep soak/week. If sure, spray chlorothalonil, Bayleton, or Immunox.

Q: Recurring fungus despite Daconil; fertilized 32-12-10 six weeks ago; soil test OK.

A: Switch to Bayleton (more systemic). Cut fertilizer to three apps/year (May, late June, late Aug). Water deeply once weekly, never after noon. Good management + judicious fungicide will gradually correct it.

Disease vs. Environment

Many brown patches are environmental: poor drainage, un-tilled soil under new sod, compacted traffic areas. Fix these first.

Diagnosis

Submit a 4×4-inch plug (half dead/half live, with roots) to your county Extension office for lab ID (~10 days).