Selectivity of nicosulfuron formulations for corn hybrids in function of nitrogen fertilization period

Abstract

Aimed in the present work to evaluate the interaction effect between periods of nitrogen coverage fertilization and different formulations of nicosulfuron herbicide over the selectivity to 2B-710 and 30K73 corn hybrids. Two experiments were conducted, simultaneously, with corn seedlings in V3 and V6 stages using treatments disposed in a factorial scheme 2x4+1, where the first factor was composed by two nicosulfuron formulations (18.8 g ha-1) (SansonTM and AccentTM) in mixture with atrazine (1250 g ha-1) and the second factor constituted by four periods of nitrogen coverage fertilization (67.5 kg N ha-1), represented by 0, 3, 6 and 9 days after herbicide application (DAAH); and an additional check without herbicide application. 2B-710 and 30K73 corn hybrids showed variable selectivity in relation to nicosulfuron herbicide application, with the major effects and symptoms of phytotoxicity occurring when nitrogen fertilization was performed in coverage in the same day of SansonTM formulation applying for V3 stage and three days from applying AccentTM to V6 stage.