Effects of plateau on tall fescue

Spring growth of tall fescue (Festuca arundinacea Schreb.) can be managed by using plant growth regulators. Plateau((R)) is an imidazolinone that could regulate tall fescue growth at low rates. Plateau was applied to tall fescue on April 7 at rates of 1.0, 1.5, 2.0, and 3.0 oz/acre a.i with an adjuvant of either Sun-It II(R) or a nonionic surfactant (NIS). Pursuit (1 oz/acre) and Embark (4 oz/acre) with MS were included along with an untreated control. Spring forage yield was reduced relative to the control by all regulators, but reductions were greater from Plateau than from Embark. Seedhead density was reduced 82% by the Embark treatment, 96% by Pursuit, and more than 99% by Plateau treatments. Foliage color was similar to that of the control where Embark and Pursuit were used but was reduced at the 2- and 3-oz/acre rates of Plateau. Stunting was also greater from treatments of Plateau compared to Embark and Pursuit treatments. Stand ratings near the end of summer were reduced in comparison to the control by Plateau rates of 1.5 oz/acre or more, but not by treatments with Pursuit or Embark. Plateau could be an effective tool to regulate the amount of fescue growth for purposes such as enabling legume establishment.