Brown Grass Blades

Healthy grass depends on good cultural management and timely disease identification and preventative measures. The North Dakota State University Extension lists fungi as the most frequent cause of declining grass. A common fungal infection causes grass blades to start turning brown.

Identification

Dollar spot disease on grass is caused by Moellerodiscus sp., Lanzia sp., and Sclerotinia sp. Fungal growth is more prevalent during spring and fall temperatures of 60 to 80 degrees F., and is favored by the presence of excessive moisture and thatch in lawns.

Damage

The disease is characterized by brown to straw-colored 1- to 2-inch spots on lawns; the spots often take on a bleached look. As the fungus spreads, the discolored spots get larger and more irregular in size, merging together to form patches. Brown grass blades display red bands running crosswise. Very fine, white, cobweb-like threads are visible on the lawn during early morning.

Control

Keeping grass in vigorous health is among the best management practices to reduce infection. De-thatch grass regularly, and avoid overfertilization; apply a top dressing of compost, and raise the mowing height.

References

• North Dakota State University Extension: Lawn Diseases
• University of California Extension: Dollar Spot