ADDITION OF PROTOX INHIBITORS HERBICIDES TO GLYPHOSATE IN THE DESICCATION OF Urochloa brizantha BRS “Piatã”

Plants of the genus Urochloa are adopted as cover crops, and desiccation is essential for implementing subsequent crops. Here, we evaluated the desiccation of Urochloa brizantha BRS “Piatã” using glyphosate associated with different protoporphyrinogen oxidase inhibitors (PROTOX). The treatments were arranged in a factorial scheme (2x5+1), consisting of two glyphosate doses of 900 and 1800 g a.e. ha-1 (D1 and D2), associated or not with carfentrazone-ethyl (20 g a.i. ha-1), flumioxazin (20 g a.i. ha-1), saflufenacil (35 g a.i. ha-1), and tiafenacil (70 g a.i. ha-1), in addition to the control treatment (without herbicides). The study was conducted in Alvorada do Sul (ALV) and Londrina (LDN), both in Paraná state, Brazil. Seven days after application (DAA), the chlorophyll index was measured. The percentage of tissue injury was assessed by the visual scale (0-100) at 7, 14, 21, and 28 DAA. At the end of the experiment, the fresh and dry shoot mass and the percentage of water (%H2O) in the tissue were measured. For the experiment in ALV, glyphosate D2 + flumioxazin reached 68.7% of injury. The percentage was reduced in all treatments in relation to the control, with D2 providing the greatest reduction. On the other hand, in LDN, no difference was observed between treatments with or without PROTOX-inhibitors. The percentage confirmed the result obtained by the visual scale, in which glyphosate at D2 resulted in an average of 90.5% control at 28 DAA, 9.5% greater than D1. In both experiments, the mixture of glyphosate and flumioxazin deserves to be highlighted as it accelerated the kinetics of plant mortality. D2 was more effective in controlling the plants (on average 8.5% greater than D1).