Cultivar, Mowing Height, and Herbicide Effects On Bermudagrass, Cynodon dactylon, Suppression in Tall Fescue, Schedonorus phoenix.

Current research at the Western Kentucky University Farm is addressing the effects of mowing height and herbicide treatment in the suppression of bermudagrass, Cynodon dactylon [L.] Pers. var. dactylon x C. transvaalensis Burtt-Davy, in plots of tall fescue, Schedonorus phoenix (Scop.) Holub. The experimental design was a split plot design. ‘KY 31’ and ‘Bullseye’ tall fescue was seeded into an established stand of bermudagrass on 9/08/2011. Mowing Heights were 7.62 cm, 10.16 cm, and 12.70 cm. The size of each plot is 1.22 m x 1.83 m. Treatments consisting of Glyphosate (Roundup) at a rate of 1.169 L/ha were applied one day prior to fescue seeding. On 4/07 and 4/30/2012, herbicide treatments consisting of Mesotrione (Tenacity), Fenoxaprop (Acclaim Extra), and Fluazifop (Fusilade II) were applied at the rates of 0.584 L/ha, 1.46 L/ha, and 0.44 L/ha respectively, to selected plots. On 7/11/2012, significant differences in turf quality occurred between herbicide treatments, with Fluazifop treatment resulting in lower turf quality. However, Fluazifop resulted in greatest bermudagrass suppression. Fluazifop reduced bermudagrass cover by 37% in ‘KY 31’ and 32% in ‘Bullseye’. Treatments receiving Mesotrione alone resulted in no bermudagrass suppression. Initially, plots mowed at 12.70 cm resulted in significantly less bermudagrass cover, however by July there were no significant differences observed in bermudagrass cover among mowing heights within each cultivar. Significant differences in broadleaf weed cover were observed with Mesotrione treated plots resulting in greatest broadleaf weed control.  ‘KY 31’ tall fescue exhibited greatest turf quality at a mowing height of 12.70 cm. In contrast, ‘Bullseye’ exhibited greatest turf quality at the 7.62 mowing height. First year data suggests that mowing height and herbicide treatments affect turf quality and bermudagrass suppression. Further information is expected to be ascertained prior to the conclusion of this research.