Impact of Irrigation Regime and Host Cultivar on Dollar Spot of Creeping Bentgrass.

IMPACT OF IRRIGATION REGIME AND HOST CULTIVAR ON DOLLAR SPOT OF CREEPING BENTGRASS

Nancy Dykema, Joseph Vargas, Jr., William Kirk, and Kevin Frank

            Dollar spot (DS), caused by Sclerotinia homoeocarpa, is an important disease of turfgrass. Irrigation practices and host resistance can impact disease incidence and aesthetics on fairway turfgrass. This study was conducted to determine the impact of irrigation regime, based on timing and frequency, and creeping bentgrass cultivar on DS incidence. Irrigation was applied at either 2200 h daily or twice weekly, or 0500 h daily on fairway plots established to each of three creeping bentgrass cultivars, ‘Declaration', ‘SRP-1WM', and ‘L-93'. ‘Declaration' and ‘SRP-1WM' were considered resistant to DS and ‘L-93' was considered susceptible. Plots watered at 2200 h daily exhibited significantly less disease than those irrigated at 2200 h twice weekly, regardless of creeping bentgrass cultivar. ‘SRP-1WM' developed the least amount of DS each year among all cultivars. In 2011 and 2013, the ‘SRP-1WM' plots receiving daily irrigation (AM or PM) did not significantly differ and exhibited less DS than those irrigated at 2200 h twice weekly for the same cultivar.