A field trial was conducted to evaluate the chemical control of Convolvulaceae weeds in soybean fields under sugar-cane rotation. The sugar-cane was harvested without burning with a layer of straw on the soil surface. The herbicides evaluated were: diclosulam plus glyphosate (0.035 + 1.440 kg ha-1, tank mix) during pre-crop and weed dissection, diclosulam alone (0.035 kg ha-1) on soybean preemergence and fomesafen (0.250 kg ha-1) on soybean postemergence. In the field the plots were arranged in a completely randomized block design, and the treatments in a 2x5 factorial design, the factors consisting of two soybean cultivars (Coodetec 206 and Monsoy 6101) and five weed management measures (weedy, weed free, diclosulam, fomesafen and diclosulam + glyphosate). The results showed that the weed densities were not sufficient to reduce soybean productivity. Diclosulam and its mixture with glyphosate provided good control of the convolvulaceae species: Ipomoea grandifolia, Ipomoea quamoclit and Merremia cissoides. The cultivar Monsoy 6101 was considered the most suitable for sugarcane rotation due to its shorter cycle.
Glycine max; Ipomoea spp.; residual herbicide; weeds
