Use of Salt to Control Annual Bluegrass in Seashore Paspalum.

Annual bluegrass is a problematic winter annual weed of seashore paspalum turf with limited herbicides for control.  Salinity tolerance of seashore paspalum may allow practitioners to apply granular salt for annual bluegrass control but application timing may influence turf tolerance.   To test this hypothesis, field and growth chamber experiments were conducted to investigate salt applications for annual bluegrass control in seashore paspalum.  In field experiments, salt applications at 1460 kg/ha effectively controlled annual bluegrass when applied at dormancy, 50% greenup, and complete greenup but annual bluegrass reestablished in treated plots after four to six weeks.  In growth chamber experiments, seashore paspalum tolerance to salt from 244 to 3900 kg/ha increased with temperatures from 10, 20, and 30° C while salt provided comparable injury to annual bluegrass across temperatures.  Overall, granular salt applications appear to provide temporary annual bluegrass control but temperature may influence seashore papsalum tolerance to applications.