The experiment was carried out in a Roundup Ready® commercial soybean field in the Pontal do Paranapanema region in Euclides da Cunha Paulista-SP, located 20º 43' 11'' S and 50º 10' 20'' W, 270 m altitude. The experimental phase was carried out from December 2006 to April 2007, under no-tillage system. The soil classification is sandy clay loam Argisol. This work aimed to evaluate the efficiency of Roundup Transorb® glyphosate formulation selectivity associated with the herbicides diclosulam, cloransulam-methyl, flumioxazina and S-metolachlor under two spray modalities (single, with glyphosate associated to the herbicides and sequential, with only glyphosate) in tropical Spiderwort (Commelina benghalensis) and little bell (Ipomoea triloba) management during soybean cultivation. The experiment was arranged in a randomized block design, with 12 treatments and 4 replications. Treatments were distributed in a factorial scheme + 2 controls (no control and clean field). The factorial scheme 2 x 5 comprises two herbicide sprays (single and sequential) and five herbicides (glyphosate, glyphosate + diclosulam, glyphosate + cloransulam-methyl, glyphosate + flumioxazin and glyphosate + S-metolachlor). Under the conditions and time the herbicides were used as well as spray dosage, the results showed that glyphosate sprayed in a single dose or sequentially, in combination with diclosulan and cloransulam-methyl in the first spray did not cause phyto-intoxication in the soybean plants. The flumioxazin and S-metolachlor combination promoted delay in the growing plants as well as in the complete formation of the culture due to the effect on plant height and branch length. Neither the herbicides tested nor the sequential spray influenced significantly soybean grain production. All treatments using single application or combined with sequential glyphosate spray promoted an excellent control of Commelina benghalensis and Ipomoea triloba.
herbicides; weed; non-tillage; soybeans
