Dollar spot is caused by a fungus. Infected areas of turf are straw-colored, matted and the size of silver dollars. Dollar spot can also infect turf along the tracks made by lawn mowers and lawns mowed higher than two inches. These infected patches are usually larger and more irregular.
What to look for:
Fine, “cobwebby” fungal threads (mycelium) are evident in infected areas in the morning, when dew is present. Individual leaf blades have an hourglass-shaped lesion, or spot, which is straw-colored with a reddish-brown margin.
- Hosts: Dollar spot is commonly found on lawns with excessive thatch and low moisture in the soil.
- Biology and Symptoms: This fungus is active from late spring through early fall. High humidity and air temperatures of 65° to 80°F encourage the growth of dollar spot.
Management and Treatment Options:
A fungicide application program may be necessary when dollar spot is prevalent. Good cultural practices will also reduce the potential for dollar spot to infect your lawn. These include removing excess thatch, maintaining adequate fertility and soil moisture, and seeding or sodding with disease-resistant cultivars. Also, do not mow when the turf is wet.