The objectives of this work were to evaluate the efficiency of glyphosate and preformulated mixture paraquat + diuron as well as the effect of the interval between herbicide applications and soybean sowing on the control and re-growth impairment of the following weeds: Digitaria insularis, Synedrellopsis grisebach and Leptochloa filiformis. The experiment was carried out in a soybean area under no-till system and was arranged in a randomized block design, with 9 treatments and four replications. The following treatments were evaluated: glyphosate applied on sowing day; one day before sowing day; two days before sowing day; five days before sowing day; paraquat + diuron 20 days before sowing day and on sowing day; glyphosate 10 days before sowing day and paraquat + diuron on sowing day; glyphosate 15 days before sowing day and paraquat + diuron on sowing day; glyphosate 20 days before sowing day and paraquat + diuron on sowing day; and control (presence of weeds). Acceptable control and re-growth impairing of D. insularis and L. filiformis were obtained when glyphosate was applied five days before soybean sowing or when sequential applications of glyphosate and paraquat + diuron were applied. Sequential applications of paraquat + diuron were not efficient in controlling or impairing re-growth of the weeds D. insularis and L. filiformis. S. grisebachii showed to be tolerant to glyphosate.
Digitaria insularis; Synedrellopsis grisebachii; Leptochloa filiformis
