Research was designed to reduce herbicide use by replacing POST herbicides with readily available ocean water to control weeds in turfgrasses. Sensitivity to salt stress was evaluated for large crabgrass, goosegrass, mimosa-vine, alyceclover, and yellow nutsedge, as well as the turfgrasses such as seashore paspalum, bermudagrass, St. Augustinegrass, and centipedegrass. Three different salinity levels, (55, 37, and 19 dS/m) and two salt-stress durations (3 and 6 d) were tested. Mimosa-vine was fully controlled at 55 and 37 dS/m. Alyceclover showed maximum injury at 95% when treated at 55 dS/m for 6 d and 90% when treated for 3 d. Large crabgrass was controlled at 55 dS/m. Goosegrass injury was up to 90% at 55 dS/m, but injured plants recovered to 48% at 30 d. Yellow nutsedge showed a maximum of 38% injury but showed 0% injury at 30 d. Among tested turfgrasses, seashore paspalum showed tolerance to pure ocean water at 55 dS/m, with maximum injury at 18%. At the same level of stress, maximum injury for bermudagrass was 30%, for St. Augustinegrass 60%, and for centipedegrass 100%. Lower levels of salt stress resulted in less injury but were still excessive for St. Augustinegrass and centipedegrass. Ocean water was shown to be an effective method to control mimosa-vine, and large crabgrass in seashore paspalum and bermudagrass turfs.
Nomenclature: Alyceclover, Alysicarpus vaginalis (L.) DC. #3 ALZVA; bermudagrass, Cynodon dactylon (L.) Pers. # CYNDA; centipedegrass, Eremochloa ophiuroides (Munro) Hack. # ERLOP; goosegrass, Eleusine indica (L.) Gaertn. # ELEIN; large crabgrass, Digitaria sanguinalis (L.) Scop. # DIGSA; mimosa-vine, Mimosa strigillosa Torr. & Gray # MIMST; seashore paspalum, Paspalum vaginatum Swartz. # PASVA ‘Adalayd’; St. Augustinegrass, Stenotaphrum secundatum (Walt.) Ktze. STPSE ‘Raleigh’; yellow nutsedge, Cyperus esculentus L. # CYPES.
Additional index words: Alternative weed control, salt stress, turfgrass salt tolerance.
Abbreviation: POST, postemergence.