Dealing With Dollar Spot
Dollar spot (Sclerotinia homoeocarpa) is a turfgrass disease commonly seen on bluegrasses, perennial ryegrass, bermudagrass, and creeping bentgrass.
Management
When mowed at lower height, fescues can also sport this disease. You may see these bleached spots pop up on the putting greens of your local golf course or maybe in your own lawn during the spring and fall. Dollar spot is caused by the S. homoeocarpa pathogen that infects the leaves of living turfgrass when night temperatures are above 50oF and day temperatures stay below 89oF. Low nitrogen fertility, humidity, and excessive wetness (dewy mornings) all also promote the pathogen. Once conditions are right and the pathogen is present, disease will present itself, leaving you to deal with the repercussions.
Dollar spot is a nuisance as it disrupts the playability of the turfgrass on a golf course, bowling green, tennis court, or any other low-mown turf. As the height of cut of the turf increases, so does the infection area. These spots will appear to be a light tan in color, or maybe even look bleached. When the infection worsens, a fluffy mycelium will begin to develop, spreading the disease even further. When you see dollar spot, you may want to be wary of your grass activities because shoes, maintenance equipment, animals, and wind can help disperse the disease. It is best to clean your equipment off after each use, and to rinse the bottoms of your golf shoes before accidentally tracking it through your backyard putting green.
Dollar spot can be reduced using cultural control methods like reduced irrigation, dew and thatch removal, maintaining a healthy fertility, and aerating the soil. The pathogen is still present and will affect the grass if these cultural practices are implemented, therefore most turfgrass managers maintain a fungicide spray schedule to mitigate the disease during seasons of high disease pressure. However, overuse can lead to fungicide-tolerance so to reduce the risk mix a systemic fungicide with a contact, or rotate fungicide classes.
Dollar Spot Resistant Products
At Barenbrug, we have a great number of products that are developed with this in mind and below are a number of them we recommend to help you succeed in areas with high dollar spot pressure.
Kentucky bluegrasses
- After Midnight
- Award
- NuGlade
- Beyond
- Impact
- Rugby II
- Everest
- Blue Chip
- Navy
- Turf Blue Pro
- Turf Blue HGT
Perennial ryegrasses
Fine fescues
Bentgrasses
Sources
Kerns, J. P. and Tredway, L. P. (2013). Advances in Turfgrass Pathology. ASA-CSSA-SSSA Turfgrass Monograph, 733- 776.
Walsh, B, Ikeda, S. S., and Boland, G. J. (1999). Biology and Management of Dollar Spot (Sclerotinia homoeocarpa); and Important Disease of Turfgrass. HortScience, 34(1): p. 13-21.