Seashore paspalum has high salinity tolerance, suggesting sodium chloride might have potential as a selective grassy weed herbicide. The objective of this research was to investigate sodium chloride rate and application timing for smooth crabgrass control and seashore paspalum and common bermudagrass injury. Five rates of sodium chloride (244, 488, 976, 1,952, or 3,904 kg ha⁻¹) were compared with quinclorac at 0.84 kg ai ha⁻¹ for controlling multileaf or multitiller smooth crabgrass. Sodium chloride at ≥ 976 kg ha⁻¹ provided excellent control (90 to 100%) of multitiller smooth crabgrass from 7 to 28 d after treatment, but ≥ 1,952 kg ha⁻¹ was required to achieve excellent control of multileaf populations. Furthermore, 976 kg ha⁻¹ of sodium chloride applied to multitiller smooth crabgrass caused minimal seashore paspalum injury (0 to 6%), comparable to quinclorac, but was more injurious when applied earlier in the spring for multileaf smooth crabgrass control. Common bermudagrass injury increased with sodium chloride rate and was > 20% from sodium chloride at 488 and 976 kg ha⁻¹ at both application timings. Overall, sodium chloride was most effective and safe on seashore paspalum when applied for smooth crabgrass control at the multitiller growth stage, whereas bermudagrass injury might be excessive at minimum rates required for control.

Nomenclature: Smooth crabgrass, Digitaria ischaemum (Schreb) Schreb. ex Muhl.; common bermudagrass, Cynodon dactylon L. (Pers.); seashore paspalum, Paspalum vaginatum (Sw.).