Assessing the Effects of Trinexapac-Ethyl on Trafficked Fine Fescue Fairways.

Low-input fine fescue species should be able to withstand typical stresses while producing acceptable turf and playing quality, all with fewer inputs of pesticides, water, and fertilizer. Research is limited on how fine fescues fairways should be managed to enhance lateral growth rate and increase divot recovery under high-play, high-traffic conditions. The objective of this experiment was to determine the impact of a plant growth regulator on recovery from divots and traffic in fine fescue fairways. A single cultivar was selected for each of the five fine fescue species—‘Treazure II’ Chewings fescue (Festuca rubra ssp. fallax), ‘Beacon’ hard fescue (Festuca trachyphylla), ‘Navigator II’ strong creeping red fescue (Festuca rubra ssp. rubra), ‘Shoreline’ slender creeping red fescue (Festuca rubra ssp. litoralis), and ‘Quatro’ sheep fescue (Festuca ovina). Twenty-five mixtures of these five grasses were developed and plots were seeded at 2 PLS cm^-2 in summer 2012 as a split-strip plot design with three replications. Following the application of 12-24-18 applied at 49.0 kg P₂O₅ ha^-1 during establishment, plots were fertilized at 98.0 kg ha^-1 N (18-0-18) per year and received no pesticides or supplemental irrigation. The main plot was with or without a plant growth regulator, the sub plot was with or without traffic, and the sub-sub plot was the fine fescue mixture. The plant growth regulator trinexapac-ethyl (Primo MAXX) was applied every 200 growing-degree days at 48 g ai ha^-1 from 1 June to 15 Oct. of 2013 and 2014. Plots received traffic treatments at six passes per week (2 passes on each of 3 days) using a golf cart traffic simulator from 1 July to 31 Aug. of 2013 and 2014. On 1 Aug. 2013, divots of uniform size and depth were removed from each sub-sub-plot with a divot harvester. Data collected included turf-quality ratings, digital images of percent green cover, weed counts, surface firmness, and measurements of divot recovery rate. Statistical analysis was performed using a linear mixed-effects model in R. Top-performing mixtures contained significant proportions of hard fescue and slender creeping red fescue. Trinexapac-ethyl had no effect on traffic or divot recovery in fine fescue fairway mixtures.