AUBURN, Ala. – Dollarspot is the most common disease people find in home lawns in Alabama. This fungal disease causes deep scars in a lawn. This damage can be serious and affects the look on well-maintained lawns. An Alabama Extension professional offers information and control options for this disease.
Dr. Austin Hagan, an Alabama Extension plant pathologist, said that dollarspot affects several types of grasses.
“Bermudagrass and Zoysiagrass lawns are the main targets of this disease,” Hagan said. “It may also be found on centipedegrass, bahiagrass and rarely on St. Augustinegrass.”
While possibly present anytime during growing season, the disease people mainly find in late summer and early fall. It spreads mainly by the moving of diseased grass clippings by people, water, wind and lawn mowers or other lawn care equipment.
The disease usually appears when days are still hot and nights are cool. If the weather is right, it may show up anytime from early spring until first frost. The disease flourishes when a heavy rain follows a week or more of hot, dry weather.
On closely mowed lawngrasses, dollarspot usually appears as circular, tan spots about 1 to 2 inches in diameter. Hagan said that if left uncontrolled, these spots will grow together, forming large areas of blighted turf.
The spots on centipedegrass are usually much larger. After a heavy dew or night rain, it is possible to find the white cottony growth of the dollarspot fungus 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.
Control of Dollarspot
Hagan says the best defense against dollarspot is good lawn management practices.
“A well-maintained lawn should be mowed once or twice a week. Zoysiagrass and Bermudagrass lawns should be mowed a height of ¾ to 1 inch,” Hagan said. “Keep centipedegrass lawns at a height of about 1½ inches. During lengthy periods of hot, dry weather, slightly raise the mowing height to avoid scalping the turf.”
Another part of good lawn management is making sure the lawn’s correct nitrogen levels are kept. Bermudagrass and Zoysiagrass lawns should receive 4 to 6 pounds of actual nitrogen per 100 square feet per year. For centipedegrass, one to 2 pounds of actual nitrogen per 1000 square feet per year is all that is needed to keep turf healthy.
Hagan said that people should water their lawn once a week during hot, dry weather.
“During Alabama summers, a healthy turf normally needs about 1½ inches of water a week,” Hagan said. “Try to avoid watering your lawn in the late afternoon or early evening.”
Hagan wrote a publication on controlling dollarspot in home laws. To download this publication, visit Alabama Extension online at http://www.aces.edu/pubs/docs/A/ANR-0493/ANR-0493.pdf. For more information, contact your county Extension office.
Featured image by shutterstock.com/karamysh.