Bermudagrass suppression and goosegrass control in seashore paspalum turf

Abstract: Seashore paspalum has gained increased popularity in Hawaii due to its salt tolerance and the use of non-potable water on golf courses. Bermudagrass and goosegrass are problem weeds infesting both fairways and greens on many seashore paspalum golf courses. Herbicide efficacy studies were conducted at the West Loch Golf Course (‘Salam’ seashore paspalum, greens cut) on the island of Oahu in Hawaii. The herbicides metribuzin, topramezone, mesotrione, and ethofumesate were evaluated in tank mixtures for bermudagrass and mature goosegrass control and seashore paspalum injury. Goosegrass was controlled with tank mixes that included topramezone (0.01 kg ha^-1) + metribuzin (0.10 kg ha^-1) with an acceptable level of seashore paspalum discoloration. Incorporating a post-spray dry down allowed for complete control of goosegrass with one spray application. Maximum bermudagrass injury was seen in treatments with mesotrione (0.07 kg ha^-1) and/or ethofumesate (1.12 kg ha^-1). Applications of mesotrione did not result in goosegrass control. Seashore paspalum turf bleaching from mesotrione and topramezone can be reduced with the addition of metribuzin and/or ethofumesate to the tank mix.