Reducing Ultradwarf Bermudagrass Putting Green Winter Injury with Covers and Wetting Agents.

Reducing Ultradwarf Bermudagrass Putting Green Winter Injury with Covers and Wetting Agents.

E. J. De Boer, M.D. Richardson, J.H. McCalla, and D.E. Karcher

As ultradwarf bermudagrass (Cynodon dactylon x C. transvaalensis) putting green use in the United States moves further north, there is increased risk of sustaining winter injury from desiccation and low temperature exposure. Protective covers are an essential tool for reducing winter injury of ultradwarf greens. Installation and removal of these covers to allow for golf during periods of favorable weather is costly and labor intensive. This research aims to define a predicted low temperature threshold when covering an ultradwarf putting green becomes necessary and to quantify the effects of a late-fall wetting agent application on winter survival and green-up during the following spring. Research was conducted on a sand-based putting green with replicated plots of ‘Champion’, ‘MiniVerde’, and ‘Tifeagle’ bermudagrass. Covering treatments were placed on the green at forecasted low temperature thresholds of -9.4, -7.8, -5.6 and -4.0 °C and were compared to an uncovered control. A single late-fall wetting agent application was applied as a split plot to each cultivar x cover treatment. Plots receiving cover treatments achieved significantly faster spring green-up than the control but were not significantly different from each other. ‘Mini-Verde’ and ‘Tifeagle’ achieved significantly faster spring green-up compared to ‘Champion’. Plots receiving a wetting agent application achieved significantly faster spring green-up in 2016 compared to the control, but the wetting agent effects were not significant in 2017. These data suggest the possibility of reducing the predicted low temperature threshold for covering greens without a significant increase in winter injury severity. This temperature reduction can reduce golf course labor costs and increase revenue with more days open for play.