CONTROLE QUÍMICO DE CAPIM BRANCO (Chloris elata)

Abstract

Chloris elata, commonly known tall windmill grass, is very problem weed in cultivated áreas where is used the chemical control with glyphosate herbicide. The objective of this work was to evaluate the efficacy of isolated or mixed herbicides, applied in post-emergence for the control of C. elata biotypes. The experiment was conducted in a randomized complete block design, with four replicates. The split-plot scheme (16 x 6) were used, considering the use of glyphosate alone or associated with acetyl coenzyme carboxylase inhibitor herbicides. Six seasons of control percentage evaluation of C. elata (7, 14, 21, 28, 35 and 42 days after application - DAA) were used. After the application of the herbicide treatments, the evaluation of the visual percentage of control and the dry mass and regrowgt of the plants were carried out. C. elata showed tolerance to glyphosate herbicide at the dose of 720 (g e.a. ha-1). The use of glufosinate ammonium herbicide in single or sequential application, resulted in mild phytotoxification and low reduction of dry mass of C. elata. Haloxifop-p-methyl applied at the dose of 62.35 g a.i. ha-1, presented moderate phytointoxication (50%) and a reduction in the dry mass production of C. elata. Glyphosate doses greater than 1,440 g ha-1, associated or not with the herbicides haloxyfop-p-methyl, clethodim, fluazifop-p-butyl, tepraloxydim, quizalofop-p-tephrolyl, phenoxaprop-p-ethyl + clethodim and haloxy-p-methyl + ammonium glufosinate and cletodim + ammonium glufosinate resulted in the control of this weed.