Effects of Various Plant Growth Regulators on the Traffic Tolerance of 'Riviera' Bermudagrass (Cynodon dactylon L.)

Data describing effects of plant growth regulator (PGR) applications on bermudagrass (Cynodon spp.) traffic tolerance are limited. A 2-year study was conducted evaluating effects of several PGRs on 'Riviera' bermudagrass (Cynodon dactylon L.) traffic tolerance. Treatments included 1) ethephon at 3.8 kg.ha(-1); 2) trinexapac-ethyl (TE) at 0.096 kg.ha(-1); 3) paclobutrazol at 0.28 kg.ha(-1); 4) flurprimidol at 0.0014 kg.ha(-1); 5) flurprimidol + TE at 0.0014 kg.ha(-1) + 0.096 kg.ha(-1), respectively; 6) ethephon + TE at 3.8 kg.ha(-1) + 0.096 kg.ha(-1), respectively; and 7) untreated control. All treatments were applied three times on a 21-d interval before trafficking. Plots were subjected to three simulated football games per week with the Cady Traffic Simulator. Traffic began 2 weeks after the last sequential application of each PGR. Turfgrass color, quality, and cover were quantified weekly using digital image analysis. Turfgrass cover measurements were used to assess traffic tolerance. Improvements in turfgrass color, quality, and cover were observed with applications of TE, ethephon + TE, and flurprimidol + TE. Turfgrass color, quality, and cover were enhanced for ethephon + TE and flurprimidol + TE compared with applications of ethephon and flurprimidol alone. Considering that no differences in turfgrass color, quality, or cover were detected among TE, ethephon + TE, and flurprimidol + TE at any time in the study, the responses observed suggest that TE may have a greater impact than other PGRs on 'Riviera' bermudagrass athletic field turf when applied before traffic stress. Chemical names used: rthephon (2-chloroethyl)-phosphonic acid; glurprimidol {alpha-(1-methylethyl)-alpha-[4-(trifluoro-methoxy) phenyl] 5-pyrimidine-methanol}; paclobutrazol, (+/-)-(R*,R*)-beta-[(4-chlorophenyl) methyl]-alpha-(1-1-dimethyl)-1H-1,2,4,-triazole-1-ethanol; trinexapac-ethyl [4-(cyclopropyl-[alpha]-hydroxymethylene)-3,5-dioxo-cyclohexane carboxylic acid ethyl ester].