HERBICIDAS ACCASE NO CONTROLE DE CAPIM-CORACANA, CAPIM-AMARGOSO E CAPIM-PÉ-DE-GALINHA E EFEITO RESIDUAL NA CULTURA DO MILHO

Abstract

Agricultural production is constantly growing and weed management in production systems is extremely important. This management is complex, as herbicide-resistant weeds are emerging every day and more plant species are being used to produce plant cover in crops, that also need to be managed. The objective of this work was to evaluate the ACCase herbicides to control Eleusine coracana, E. indica and Digitaria insularis, and identify residual effects in Corn crop. Three experiments were carried out, the first consisting of 15 treatments in a randomized block design (RBD) with four replications, testing clethodim, haloxyfop, quizalofop, glyphosate dosages, association of glyphosate with mineral oil dosages, urea, ammonium sulfate, and ACCase in autumn desiccation of finger millet sown after soybean cultivation. The treatments were applied 93 days after sowing of finger millet and weekly visual control evaluations were carried out up to 35 days after application. The second work was carried out on goosegrass and sourgrass, in a naturally infested area, where the herbicides clethodim, haloxyfop and quizalofop each alone and in mixture with 2,4-D were evaluated. Seven treatments were carried out in RBD with four replications, which were evaluated weekly for visual control up to 35 days after application. The third trial was carried out in a corn crop, with seven treatments, consisting of a control treatment and the application of clethodim, haloxyfop and quizalofop at 7 and 14 days before corn sowing. This work was carried out in the corn hybrids AS 1868 PRO3, FS 610 PWU and P 3707 VYH, evaluating the phytotoxicity of the crop up to 21 days after sowing, plant height in V4 stage, final plant height, ear insertion, stem diameter, ear diameter, ear length, number of rows of grains per ear, number of grains per row, thousand-grain weight and productivity. All variables analyzed were submitted to analysis of variance and the means compared by the Scott-Knott mean test, 5% significance. Glyphosate showed 100% control over finger millet, ACCase herbicides showed control efficiency below 60% over Eleusine sp.; ACCase herbicides showed close to 80% control over sourgrass, but lost efficiency when mixed to 2,4-D. The ACCase herbicides showed a residual effect on the hybrid P 3707 VYH when applied 7 days before sowing. ACCase herbicides have a low effect on Eleusine grasses and good control on Digitaria insularis when applied without 2,4-D. These herbicides, when applied close to corn sowing, compromise the productivity of some corn hybrids.