ABSTRACTA COMBINATION OF LIGHTWEIGHT ROLLING AND SAND TOPDRESSING TO DECREASE FUNGICIDE INPUTS AND ENHANCE GOLF COURSE FAIRWAY TURF QUALITYByThomas O. Green Dollar spot (Sclerotinia homoeocarpa F.T. Bennett) is a pervasive turfgrass disease in the upper Midwest affecting turfgrass quality, decreasing golf course playability, and resulting in millions of dollars spent on frequent fungicide applications. Michigan State University scientists observed reduced dollar spot infection in putting greens that were rolled several times weekly. Others observed less incidence of disease in sand-topdressed putting greens. We hypothesized that dollar spot infection in fairways would be decreased by sand topdressing and by rolling thereby reducing the need for frequent fungicide treatments. Two research projects were devised to address the practicality of this disease management strategy. The first project objective was to examine dollar spot severity responses in an Agrostis stolonifera L. and Poa annua L. fairway to varying frequencies of lightweight rolling and to sand topdressing with no fungicide application. Sand topdressing reduced infection by 50%. Cumulative effects of rolling were investigated with the one, three, and five time weekly rolling treatments. The three and five time rolling treatment had significantly less disease compared to the control during the period of dollar spot activity. The second project assessed the effects of different fungicide application rates combined with sand topdressing and lightweight rolling on dollar spot disease in fairway turf. All the fungicide application rates, applied monthly, improved turfgrass quality and normalized difference vegetation index (NDVI) responses compared to the control. Moreover, as rolling frequency increased from 0 to 3x weekly on the no fungicide plots, sand topdressing improved turf quality and reduced dollar spot incidence.
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