Rolling and Dew Removal Effects on Dollar Spot Disease of Creeping Bentgrass.

Dollar spot (caused by Sclerotinia homoeocarpa) is the most common disease on golf course turfs in the United States. A field study evaluated the effect of lightweight rolling on dollar spot incidence of creeping bentgrass (Agrostis stolonifera L. ‘Independence’) maintained at 12.7 mm on a sandy loam in North Brunswick, NJ. A 2 x 2 factorial arranged in a randomized complete block design with four replications was used to evaluate the time [morning (AM) or afternoon (PM)] and frequency (3 or 6 d wk^-1) of lightweight rolling during the fall of 2015 and spring of 2016. The design included two additional treatments: morning removal of dew using an absorbent fabric and an untreated control. Plots rolled in the morning when dew was present had the greatest impact on the area under disease progress curve (AUDPC), reducing AUDPC by 52 and 33% compared to PM rolling during the fall and spring, respectively. The frequency of rolling had less of an effect on dollar spot incidence, but interacted with time of rolling. By late September 2015, rolling 6 d wk^-1 increased the effectiveness of AM rolling at reducing disease incidence compared to AM rolling 3d wk^-1, whereas rolling frequency did not affect disease with PM rolling. There was no effect of rolling frequency on disease during the spring regardless of the time of rolling. Removal of dew using an absorbent fabric reduced AUDPC by 74 and 53% during the fall and spring, respectively, compared to the untreated control, which was similar to the disease reduction from AM rolling 6 d wk^-1 during the fall of 2015. This research will be continued during the fall of 2016.