Golf Course Management

JUL 2013

Golf Course Management magazine is dedicated to advancing the golf course superintendent profession and helping GCSAA members achieve career success.

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research Programs for annual bluegrass control Untreated Trimmit 2 SC (paclobutrazol, Syngenta) ‡ Rate Program description† — Treatment — 8-16 ounces/acre (0.6-1.2 liters/hectare) Legacy 1.51 L (trinexapac-ethyl + flurprimidol, SePRO) 10 ounces/acre (0.7 liter/hectare) Cutless 1.3 SC (flurprimidol, SePRO) 24.6 ounces/acre (2.5 liters/hectare) Velocity 17.6 WDG (bispyribac-sodium, Valent) 0.7 ounce/acre (49 grams/hectare) Xonerate 70 WG (amicarbazone, Arysta LifeScience) 1 ounce/acre (70 grams/hectare) Four spring applications beginning mid-February with sequential applications 1 week apart. Methiozolin 2 EC (methiozolin, Moghu Research Center) 32 ounces/acre (2.3 liters/hectare) Initial application made in mid-October with sequential applications 1 week apart. Spring applications resumed mid-February; 3 fall, 3 spring applications. Methiozolin 2 EC 64 ounces/acre (4.6 liters/hectare) Initial application made in mid-October with a sequential fall application 4 weeks after initial. Additional spring application in mid-February. 0.5 + 0.5 ounce/acre (49 + 49 grams/hectare) Four spring applications alternating products 1 week apart; 2 Velocity and 2 Xonerate applications. 8-16 ounces/acre + 0.5 ounce/acre (0.6-1.2 liters/hectare + 49 grams/hectare) Trimmit program as described above with addition of 4 spring Xonerate applications beginning midFebruary with sequential applications 1 week apart. Velocity 17.6 WDG + Xonerate 70 WG Trimmit 2 SC + Xonerate 70 WG First application of Velocity and PGR in mid-October with sequential applications following 3 weeks apart. Applications ceased in mid-December and resumed mid-February; 4 fall, 4 spring applications. † Fall applications were initiated Oct. 6, 2010; Oct. 12, 2011; and Oct. 23, 2012. Spring applications were initiated Feb. 23, 2011; Feb. 13, 2012; and Feb. 27, 2013. First and second applications of Trimmit made at 8 and 12 ounces /acre, respectively, with all additional applications made at 16 ounces/acre. ‡ Table 1. Treatments, rates and descriptions of programs evaluated for annual bluegrass control in creeping bentgrass putting greens at the Walker Golf Course, Clemson, S.C., and Cross Creek Plantation, Seneca, S.C. including annual bluegrass density, seedhead suppression and creeping bentgrass turf quality. Additionally, data were obtained for creeping bentgrass phytotoxicity, plot density and bermudagrass green-up, but these data are not presented. Annual bluegrass density was visually estimated using a scale of 0% to 100%, where 0% = no annual bluegrass and 100% = complete annual bluegrass coverage. Annual bluegrass control values were calculated using visual estimates by determining the percent annual bluegrass density reduction for each plot. Seedhead suppression was calculated as a percentage of the untreated control and was evaluated using a scale of 0 to 9, where 0 = no annual bluegrass seedheads and 9 = bright white seedheads. Turfgrass quality was visually evaluated using a scale of 1 to 9, where 1 = brown, dead turfgrass, 9 = dark green, dense, uniform turf, and 7 was considered the minimum acceptable turf quality for a golf course green. Experimental design The experimental design for each study was 88 GCM July 2013 a randomized complete block with four replications. Plot sizes were 5 feet × 26 feet (1.5 meters × 8 meters) at Walker GC and 5 feet × 6.5 feet (1.5 meters × 2 meters) at Cross Creek Plantation. Annual bluegrass control, seedhead suppression and turf quality were statistically analyzed to evaluate the effect of site on treatments. Treatment performance was not statistically equivalent at both sites with respect to all ratings, therefore, results are presented and discussed separately for each site. Results Annual bluegrass control, seedhead suppression and turf quality data are presented from a fnal spring rating date after all treatments had been applied for two years at both sites. Although statistical analysis revealed treatments did not perform equally at both sites, four treatments provided clear separation from all other treatments with respect to annual bluegrass control and seedhead suppression.

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