If you're signed up for Golfdom's e-newsletters, you already got the below e-blast from Dr. Karl Danneberger regarding Dollar Spot. If you're not signed up for our e-newsletters, you can sign up for them here.
With summer's arrival the potential for dollar spot severity increases with relatively warm, humid weather present through much of the northern and eastern United States. Dollar spot is a serious problem on annual bluegrass and creeping bentgrass turf through the fall; and increasingly on bermudagrass -- especially the ultradwarfs -- and seashore paspalum during late summer. The pathogen, Sclerotinia homoeocarpa, actively grows and infects when temperatures are between 60 and 86 F. White mycelium is often present in the mornings when dew is present. With morning fog becoming more frequent, this will only increase the severity and activity of dollar spot.
Cultural practices to reduce disease severity center on soil/leaf moisture and nitrogen fertility. Prolonged periods of wetness when temperatures are favorable are conducive for disease symptoms. To reduce disease severity try practices that help reduce leaf wetness, including dew removal through a light morning syringe or whipping or dragging the turf. This would be especially helpful on the days fairway mowing is not done. For greens, rolling after mowing has been reported to reduce the incidence of dollar spot. In addition, keeping the soil moisture on the dry side can help reduce dollar spot. Nitrogen levels should be maintained at an adequate level.
Karl Danneberger, Ph.D., Golfdom's science editor and a turfgrass professor from The Ohio State University, can be reached at firstname.lastname@example.org