Yellowing Bahia Grass

Bahiagrass (Paspalum notatum Flugge) is a low-maintenance native grass of Brazil that grows well in less fertile and sandy soil. The coarse-textured grass is highly drought tolerant. A fungal disease causes yellowing grass.

Identification

Bahiagrass is susceptible to dollar spot disease caused by Moellerodiscus sp., Lanzia sp. or Sclerotinia homeocarpa. The fungal growth increases in temperatures of 60 to 80 degrees Fahrenheit and periods of high humidity. Drought-stressed grass with excessive thatch is more prone to the disease.

Damage

The disease starts with the appearance of 1- to 5-inch round, discolored areas on grass that go from yellow to brown as grass dies. Over time the spots grow larger and merge to create large, irregularly shaped areas. Grass blades appear water-soaked first and have a red band across the blade. White, thread-like fungal bodies are visible on grass in the morning.

Control

Keep grass in good health with adequate water and fertilizer and top-dress with compost. Apply nitrogen-rich fertilizer as nitrogen deficiency often leads to disease development. Dethatch grass regularly and increase mowing height. Recommended chemicals include chlorothalonil, fenarimol or iprodione.

References

• University of Florida Extension: Bahiagrass for Florida Lawns
• University of California Extension: Dollar Spot