Dollarspot Common Disease on Alabama Lawns

            Dollarspot is the most common disease on home lawns in Alabama.  Bermudagrass and Zoysiagrass lawns are the main targets of this disease but serious outbreaks can also occur on centipedegrass lawns, says Dr. Austin Hagan,  a plant pathologist with the Alabama Cooperative Extension System.

            The disease usually appears when days are still hot but nights are cool.  Dollarspot strikes in late summer or early fall after heavy rains have broken a week or more of hot, dry

weather.  If the weather is right, it may show up anytime from early spring until first frost.

            On closely mowed lawngrasses, dollarspot usually appears as circular, tan spots about one to two inches in diameter. 

“Left uncontrolled, these spots will grow together, forming large areas of blighted turf,” Hagan says.   

The spots on centipedegrass are usually much larger.   After a heavy dew or night rain, the white cottony growth of the dollarspot fungus may be seen in the areas of damaged turf.

            Mowing too low or high, along with low nitrogen fertility, often increases the severity of dollarspot on both Bermudagrass and Zoysiagrass lawns.  This disease also tends to be more of a problem on all turfgrasses after several weeks of dry weather.

            Hagan says the best defense against dollorspot is growing good grass. 

“A well-maintained lawn should be mowed once to twice a week. Zoysiagrass and Bermudagrass lawns should be mowed ¾ to 1 inches. Keep centipedegrass lawns at a height of about1 ½ inches.  During lengthy periods of hot, dry weather, slightly raise the mowing height to avoid scalping the turf.”

            Bermudagrass and Zoysiagrass lawns should receive a total of 4 to 6 pounds of actual nitrogen per 100 square feet a year. For centipedegrass, 1 to 2 pounds of actual nitrogen per 1000 square feet a year is all that is needed to keep turf healthy.   

            Water your lawn once a week during hot, dry weather, Hagan adds.  During Alabama summers, a healthy turf normally needs about 1 ½  inches of water a week.  Try to avoid watering your lawn in the late afternoon or early evening.

Source:  Dr. Austin Hagan, Plant Pathologist, Alabama Cooperative Extension System, (334) 844-5503