Close Look at Dollar Spot on Bentgrass

Dollar spot is a chronic disease of creeping bentgrass (Agrostis stolonifera) and wintergrass (Poa annua L.) turf. The pathogen, Sclerotinia homoeocarpa, actively grows and infects when temperatures are between 15 and 30 C. White mycelium is often present in the mornings when dew is present. Cultural practices for reducing the conditions favourable for this disease include reducing the leaf wetting period.

Prolonged periods of wetness when temperatures are favorable are conducive for disease symptoms. Practices to reduce the wetting period include dew removal through a light morning syringe or whipping or dragging the turf. In addition, irrigate when the likelihood of prolonged wetting is reduced.

The photographs show common symptoms of dollar spot including overall symptoms, leaf lesions, and type of mycelium present on creeping bentgrass.