Penoxsulam and Pronamid Applications for Perennial Ryegrass Removal in Overseeded Bermudagrass Turf in a Semi-Arid Environment.

Penoxsulam was applied with and without pronamid to overseeded bermudagrass for evaluation as turfgrass transition aids in the spring of 2013. Treatments were applied “early” on May 5^th, and “late” on June 4^th.  Penoxsulam was always applied at the rate of 2.83 kg ai/h, while pronamid was applied as a tank mix component at  12.20, 24.4, or 36.6 kg ai/h.  Pronamid was also applied alone at 48.8 kg ai/h on both dates.  In addition penoxsulam was applied alone as a repeat application (early and late) as well.  On June 26^th, 2013, as a repeat application (early and late applied) penoxsulam treated turf had 69% plot bermudagrass cover, compared to 33% (applied early) and 54% (late only). The UTC had only 34% bermudagrass  on that date.  The quickest return to bermudagrass on calendar date from the early applied schedule occurred on July 13th for penoxsulam applied as the tank mix with pronamid (36.6 kg ai/h) or from pronamid applied alone at 48.8 kg/ai/h.  These two treatments had 68% and 74% bermudagrass plot cover respectively on June 13th (43 DAA/1: 9 DAA/2). Penoxsulam plus pronamid ( applied at 12.20 kg ai/h) produced the best quality turf  along with enhanced  transition  when applied early or late, having 3 to 10 times more bermudagrass  than the UTC when applied early,  and 2 to 4 times more bermudagrass when applied late.  This tank mix finalized with 94% and 85% bermudagrass cover, while the UTC had 64% bermudagrass on July 9^th.  Pronamid caused necrosis at higher tank mix rates and when applied alone at  48.8 kg ai/h,  which decreased turfgrass quality at the expense of  a more rapid bermudagrass return.