Tank mixture of glyphosate and 2,4-D applied on RR® maize crop.

Herbicide tank-mixing is often carried out by farmers aiming to control weeds in crops. Thus, it is important to evaluate the effects of these mixtures regarding the selectivity of crops. The aim of this work is to assess the selectivity of increasing doses of herbicides (glyphosate and 2,4-D), applied alone or as a mixture, on maize crop. Two experiments were carried out in randomized blocks, with four replications, during two crop years. The evaluated variables were: phytotoxicity, plant height, stem diameter, ear length, number of rows per ear, number of grains per row, mass of 1,000 grains and grain yield. The herbicide, 2,4-D, when applied in mixture with glyphosate caused severe phytotoxicity symptoms on maize. Grain yield and growth characteristics were not affected by the herbicides applied alone or as a mixture. Increasing doses of 2,4-D caused severe phytotoxicity symptoms on hybrid Status VIP3. Increasing doses of glyphosate did not show phytotoxicity symptoms and are not directly correlated to any injury caused by 2,4-D in the SX 5885 VIP3 maize hybrid.