Resistência de Eleusine indica (L.) Gaertner aos herbicidas inibidores da ACCase e EPSPs em municípios do Médio-Norte Mato-Grossense

Abstract

In 2003, the first Eleusine indica (L.) Gaertner (Goosegrass) resistance case was reported to herbicides in Brazil, to ACCase-inhibiting (Acetyl-CoA carboxylase) herbicides. Moreover, after the commercial release of the Roundup Ready® technology in 2005, cases of resistance of this species to glyphosate were registered. Thus, in view of the reports of escapes from treatments with ACCase-inhibiting and also EPSPs in agricultural areas, the objective of this work was to identify and report the resistance of E. indica biotypes collected in counties in the Middle-North region of the state of Mato Grosso to clethodim, haloxyfop-R-methyl and glyphosate herbicides. For this purpose, 26 biotypes collected in Ipiranga do Norte, Lucas do Rio Verde, Nova Ubiratã, Sorriso, Tapurah e Vera were evaluated. For each biotype, screening tests were carried out with the application of the recommended dose to control the species in soybean and cotton crops: clethodim (108 g ha-1), haloxyfop-R-methyl (60 ha-1) and glyphosate (1,440 g ha-1). Surviving biotypes from screenings were separated to conduct dose-response curve experiments. The experiments were composed of 11 doses of glyphosate and haloxyfop-R-methyl (0D, 1/32D, 1/16D, 1/8D, 1/4D, 1/2D, D, 2D, 4D, 8D and 16D) or 9 clethodim doses (0D, 1/32D, 1/16D, 1/8D, 1/4D, 1/2D, D, 2D and 4D), where D is the recommended dose. Of the 26 biotypes evaluated, 20 were suspected of resistance to at least one herbicide, one for clethodim, 19 for haloxyfop-R-methyl, and six for glyphosate. There is occurrence of a biotype with resistance multiple to the herbicide glyphosate and haloxyfopR-methyl, collected in the counties of Sorriso-MT. In addition to this, two other biotypes confirmed simple resistance to the herbicide haloxyfop-R-methyl, collected in Tapurah-MT. There has been no confirmed resistance to clethodim.