Efficacy and selectivity of acetochlor isolated and mixed with atrazine, in corn

Abstract

This experiment was intended to evaluate the selectivity to maize hybrid AG 30 I O and efficiency of acetochlor herbicide alone and tank mixture with atrazine applied in preemergence to control Cenchrus echinatus, Brachiaria plantaginea, Digitaria horizontalis, lndigofera hirsuta, Bidens pilosa and lpomea grandifolia . The experiment was conducted in laboticabal, SP, on red oxissol. Treatrnents inc1ued acetochlor 2.52,3.36 and 4.20 kg!ha, acetochlor/atrazine 3.76, 4.38 and 5.0 I kglha, and the commercial pattem atrazine/metolachlor at the rate of 3.50 kg!ha, besides controls with and without weeds. The herbicides were applied with costal sprayer, to constant pressure (2.8 kgf/cm-), with four nozzles XR 11002 with equivalent spray volume of200 Llha. The best results were obtained with metolachlor/atrazine 3.50 kg!ha and with two rates of acetochlor/ atrazine (4.38 and 5.0 I kg!ha) for the weed control. Despite the slight reduction at the beginning of growth on maize treated with acetochlor, they recovered quickly making the utilization of the acetochlor on the tested hybrid a possibility.