Response of Cotton (Gossypium hirsutum) to Dicamba

Abstract

Single over-the-top and directed applications of dicamba (3,6-dichloro-o-anisic acid) were made to cotton (Gossypium hirsutumL. ‘Deltapine 16′). Dicamba applied over-the-top of cotton caused foliage malformation for about 6 weeks. Dicamba (32 g/ha) applied to cotton foliage 3 to 15 weeks after emergence reduced average cotton yields. Applications of 16 to 64 g/ha of dicamba over-the-top of cotton before bloom had less effect on cotton foliage, yield, boll components, and fiber properties than application at bloom. Directed applications of dicamba to the soil or to the base of cotton and soil caused foliage malformation but did not affect cotton yield, boll components, and fiber properties.