Gray Leaf Spot

Grass Affected

Primarily St. Augustinegrass, ryegrass, and fescue but can affect most turfgrasses.

 

Diagnostic Description

  • Appears in leaves and sheaths as small round oval spots that are brown to ash-gray in color with dark purple to reddish-brown borders. Affected areas may have an unhealthy “scorched” look, and the spots may be covered with a gray, velvety mold. Severely affected leaves wither and die resulting in turf thinning.

 

Conditions Favoring Infestation and Typically Yearly Occurrence

Favored by warm, humid, rainy weather, excess nitrogen, triazine herbicides, and newly planted areas. Summer.