Dollar spot (Sclerotinia homoeocarpa) is a common and persistent disease of bentgrass fairways. Fairway turf typically comprises 30 to 40 acres on golf courses. Fungicide applications to control dollar spot can be expensive and have environmental consequences. Rutgers University is evaluating dollar spot disease progress and severity on bentgrasses. The scientists also are looking at two weather-based models for predicting dollar spot epidemics. The effectiveness of fungicide timing is another goal of the research.
The first study included six bentgrass cultivars with varying resistance to dollar spot. Researchers evaluated dollar spot occurrence every two to five days. They compared observations to a growing degree-day and a weather regression model (Figure 1). For susceptible varieties, the models worked well in the first year (2015) but overpredicted in the second year (2016).