‘Mini-Verde' Bermudagrass Putting Green Responses to Variable Rates of Foliar N and Trinexapac-Ethyl.

            As a relatively new ultradwarf bermudagrass cultivar,’Mini-Verde’ (Cynodon dactylon (L.) Pers. X C. transvaalensis Burtt-Davy) used as putting greens in the transition and the southern states, there is a lack of information on foliar N treatments and variable of plant growth regulator rates during the growing season for the interaction with dollar spot potential maintained as putting greens.  Therefore, a two- year, two-site putting green study was conducted in 2010 and 2011 in Marietta and Clemson, SC, respectively with putting green constructed as USGA greens with 85:15 sand and peat-moss mixture. The study included 98, 196, 294, and 392 kg N ha^-1 yr^-1  with a 7 to 10 day intervals and trinexapac-ethyl (TE) applications were started early July each year and were carried on till end of August with a total of 7 applications each year at rates of 0.006, 0.012, and 0.024 a.i. L ha^-1.  The foliar fertilizations were initiated in June each year and finished in September with only July and August applications with TE. The foliar fertilizers were Progress Turf 10-3-5 and 5-0-7 foliar fertilizers at a ratio of 1:2 for each application.  The foliar fertilizer carry volume was 957 L ha^-1 with tank mixed of the foliar fertilizers and TE.  All the applications were conducted in early evenings to minimize volatilization and potential fertilizer burns with a minimum of three hours without irrigations and rainfalls. During the study, no fungicides had been applied to the plots with plots mowed at 3.2 mm daily with one core cultivation in May or June in 2010 and 2011. The turf quality, root weight, thatch mass, dollar spot infection rate, ball rolling, and clipping yields have been collected and analyzed for the study. Treatments received 196 kg N ha^-1 yr^-1 or above demonstrated acceptable turf quality and all treatments received 294 kg N ha^-1 yr^-1 demonstrated less dollar spot infections.  Treatments received 98 kg N ha^-1 yr^-1 had highest dollar spot potential with unacceptable turf quality.