Seashore Paspalum Seedhead Control and Growth Regulation with Flazasulfuron and Trinexapac-Ethyl.

Seashore paspalum [Paspalum vaginatum (Sw.)] is used on golf courses in warm temperate regions but prolific growth and seedhead development may reduce turfgrass quality.  Field experiments were conducted to investigate efficacy of flazasulfuron and trinexapac-ethyl on seashore paspalum seedhead suppression, clipping reduction, and canopy height.  Clipping reductions and seedhead suppression from nontreated increased with flazasulfuron rate from 4.5 to 27 g ai/ha by two to four weeks after treatment.  Trinexapac-ethyl at 96 g ai/ha alone provided erratic levels of seedhead suppression but reduced clippings by ≈ 50 to 75% from nontreated by two to four weeks after treatment.  On several dates, trinexapac-ethyl enhanced clipping reductions and seedhead suppression from flazasulfuron.  Trinexapac-ethyl exacerbated seashore paspalum injury from high flazasulfuron rates on several dates but injury never exceeded 23%.  Seashore paspalum height was reduced by 50% from trinexapac-ethyl in unmowed areas after eighteen weeks.  Flazasulfuron at 18 or 27 g/ha with trinexapac-ethyl provided consistent seedhead suppression and clipping reductions ranging ≈ 70 to 95% of nontreated.  These tank-mixtures have promising implications for use in seashore paspalum golf course fairways.