INFLUENCE OF TRINEXAPAC-ETHYL ON COLD TOLERANCE AND NONSTRUCTURAL CARBOHYDRATES OF SHADED SUPINA BLUEGRASS

Turf in many stadiums suffers from shading imposed by the stadium infrastructure. The cold tolerance of shaded turf may be less than that of turf in full sun due to reduced nonstructural carbohydrates (NC) needed for winter respiration and spring regrowth. Turf injury or death from the combination of cold and shade results in decreased quality and delayed use for early spring athletic events. Plant growth regulators (PGRs) have been shown to increase turf quality and influence NC levels in shaded conditions; however their effect on the cold tolerance of shaded cool-season turf is not known. In a two-year field study, we found that sequential low-rate applications of trinexapac-ethyl (TE) increased winter survival rate of 80% shaded supina bluegrass (Poa supina Schrad.) in one of two years. Trinexapac-ethyl ameliorated NC losses during winter without significantly affecting regrowth.