Manejo de plantas daninhas em milho "RR" com herbicidas aplicados associados ao glyphosate

Abstract

The objective of this work was to evaluate the effectiveness, selectivity and grain yield components of RR maize as a function of herbicide application in isolation or in combination with glyphosate. The experimental design was a randomized block design, with four replications. The herbicides used were: atrazine, atrazine + simazine, atrazine + oil, atrazine + s-metolachlor, nicosulfuron + mesotrione, glyphosate applied pre- and postemergence, some isolates and others in tank mix, plus two controls one weeded and infested. Phytotoxicity on 2A521 PW maize hybrids and control of papaya, forage turnip and sunflower were evaluated at 7, 14 and 21 days after application of treatments (DAT). Grain yield components were determined in the corn harvesting: spike insertion height, number of rows per spike, number of grains per row, mass of one thousand grains and productivity. All herbicidal treatments caused phytotoxicity below 6%. At 7, 14 and 21 DAT all the herbicides present weed control, mainly of the sunflower that was of 100% to the 21 DAT. Only in the infested control did the corn grain yield decrease. It is concluded that the control of weeds on the corn crop is very important for high yields.