Diagnosing Brown Circles in New Bermudagrass Sod

Bermudagrass Decline or Leaf Spot?

An Arkansas homeowner installed bermudagrass sod in Dec 2006. By summer, brown circles (>24″) appear, with 30–50% brown blades near the house. Soil was contractor fill (low fertility). Weather: 80–90°F with heavy rain.

Likely Diseases

• Bipolaris cynodontus (Leaf Spot) – favored by wet, warm conditions.
• Gaeumannomyces graminis (Bermudagrass Decline) – attacks weakened sod; roots turn brown, lose feeder roots.

Diagnostic Steps

1. Check roots: brown, lacking feeder roots = decline.
2. Scout for leafhoppers or grubs (few = not primary cause).
3. Confirm excessive moisture history.

Management

• Improve drainage; avoid daily watering.
• Apply fungicide labeled for bermudagrass diseases if confirmed.
• Topdress with compost to build soil health.
• Mow at 1.5–2″ with sharp blade; leave clippings.

Sod on poor fill is inherently stressed; long‑term fix is soil building.