Diclosulam as a strategy for pre-emergence control of two <i>Borreria</i> species in different types of soils

Diclosulam is widely used for pre-emergent weed control in soybean crops, but information on its effectiveness against <i>Borreria</i> spp. (<i>Borreria</i> spp., syn. <i>Spermacoce</i>) is limited, especially considering physicochemical attributes of soils. This study evaluated diclosulam efficacy in the pre-emergence control of <i>Borreria spinosa</i> and <i>Borreria verticillata</i> in three soils. Two experiments were conducted using a 9 × 3 + 3 factorial design, with nine diclosulam doses (0.27 to 35 g a.i. ha^-1), with a treatment without herbicide and three different types of soils (Oxisol, Inceptisol, and Sandy Oxisol), with four replications. Injury level (%) was assessed at 21, 35, and 55 days after application (DAA), enabling control calculation rate (C₅₀ and C₉₀) and growth reduction doses (GR₅₀ and GR₉₀) were calculated, representing 50% and 90% of control and reduction shoot dry mass, respectively. Diclosulam effectively controlled <i>Borreria</i> spp. in all soils evaluated. Estimated doses for <i>B. spinosa</i> control, ranged from 6.36 to 23.43 g a.i. ha^-1 (C₉₀) and 0.06 to 4.80 g a.i. ha^-1 (GR₉₀). For <i>B. verticillata</i>, C₉₀ ranged from 0.72 to 30.86 g a.i. ha^-1 and GR₉₀ from 1.06 to 5.30 g a.i. ha^-1. Both species were sensitive to diclosulam, supporting its use for pre-emergence control of <i>Borreria spinosa</i> and <i>Borreria verticillata</i> in soils with different physicochemical attributes.