Travis Gannon, Fred Yelverton, and Leon Warren
It’s approaching the time of year turfgrass managers will be seeding tall fescue. Summer 2010 has been an exceptionally tough year on tall fescue in many areas of the state due to above-average temperatures and drought conditions. Depending on weed pressure, an herbicide application may be warranted prior to seeding. Of particular note is crabgrass (Digitaria species) prior to fall-seeding. Crabgrass can form dense mats and may inhibit tall fescue from uniformly germinating if not treated. For crabgrass control prior to fall-seeded tall fescue, selective herbicide options in tall fescue include quinclorac (Drive, Drive XLR8, QualiPro quinclorac, etc) while nonselective herbicide options include glyphosate (Roundup Promax, Touchdown Pro, many generic formulations) or glyphosate plus diquat (Quikpro). Quinclorac treatments should include a methylated seed oil. Although quinclorac and glyphosate-containing products do not have a tall fescue seeding restriction, for maximum herbicide activity, cultural practices (scalping, core aerification, vertical mowing, etc.) should be delayed for three to five days after application. Many broadleaf products have a tall fescue seeding restriction. 2,4-D-containing products (Trimec, Triamine, Speedzone, etc.) have a 7 – 30 day seeding restriction for tall fescue. Controlling weed species prior to tall fescue seeding helps ensure uniform germination and successful establishment.