The objective of this study was to evaluate the selectivity of the sulfentrazone molecule in post emergence in the sunflower crop. The experiment was conducted in 2014 at Campo Novo do Parecis. The experimental design was a randomized complete block design with nine treatments and four replications. The treatments consisted of seven rates of sulfentrazone (100, 125, 150, 175, 200, 225 and 250 mL ha-1) and two controls, one with manual weeding and one without weeding. The application of the herbicide was done with CO2 pressurized costal sprayer and equipped with an application bar containing five tips of the Teejet XR 110 02vs model, with application volume of 200 L ha-1. It was evaluated the phytotoxicity (%), chapter height, stem diameter, mass of the chapter, mass of achenes per chapter, mass of the plot and mass of thousand achenes. There was a reduction in the chapter height at rates of 225 and 250 ml p.c ha-1, while in the other variables no significant differences were observed. Up to 14 days after application (DAS), injuries were observed, which disappeared in the assessment performed at 21 DAS. The yield of sunflower crop was not affected by the doses of sulfentrazone. Sulfentrazone doses were selective for sunflower cultivation.
