Suppression of Seashore Paspalum in Bermudagrass with Herbicides Open Access

A mixture of seashore paspalum (Paspalum vaginatum Swartz) with bermudagrass (Cynodon spp.) results in an overall poor quality turf on golf course fairways. A field experiment was conducted at two locations during 1997 in Hawaii to determine if herbicides would control paspalum encroachment without causing undesirable injury to the bermudagrass. Three applications of Asulox (asulam) applied alone at a total rate of 4.4 kg/ha (4.0 lb/A) or with Image (imazaquin) suppressed paspalum ≥97% by 8 weeks after the initial treatment and ≥83% by 10 weeks. The suppression from three applications of Trimec Plus (MSMA + 2,4-D + mecoprop + dicamba) at a total rate of 11.1 kg/ha (9.6 lb/A) was ≥63% at 8 weeks and ≥70% by 10 weeks. Paspalum suppression from an initial application with Trimec Plus followed by two Asulox treatments was not advantageous, compared with three Asulox treatments. Three applications of Trimec Plus suppressed at least 70% paspalum by 10 weeks. The suppression was poor when treated with Ally (metsulfuron) and sequential applications with Surflan (oryzalin) and MSMA. Tifway bermudagrass (C. transvaalensis x C. dactylon) was severely injured when treated with all herbicides except Ally and Surflan plus MSMA. Maximum injury ranged from 40% when treated sequentially with Trimec Plus and Asulox, to 50% when treated with Asulox, 57% when treated with Asulox plus Image, and 91% when treated with Trimec Plus. By 10 weeks, bermudagrass had started to recover but the overall injury ranged from 28% to 40%.