Revista Brasileira De Herbicidas 2016; 15(2): 157-164
Perennial sourgrass control in full flowering growth stage
The sourgrass is a difficult plant to control, because the vegetative survival characteristics and mainly because the glyphosate resistance. The aim of this study was to evaluate the efficacy of grass herbicides to control the perennial sourgrass in full flowering growth stage. It were installed two field experiments, in the first experiment, it was tested 4 graminicides in a single application and rate the percentage of control at 14 and 28 DAA. In the second experiment, it was applied 17 treatments (application A) and after 35 days it was sprayed the sequential application using clethodim + glyphosate (Application B), in this experiment it was evaluated the percentage of control at 14, 28 and 35 days of the first (A) and the second application (B), as well the dry biomass. In the first experiment, none treatment provided acceptable control using the single application. In the second experiment, the results showed that the first application also were not effective to control the sourgrass, however 35 days after the sequential application (B), the treatment using haloxyfop-methyl at 100 g a.i ha-1 associated with herbicide clethodim were efficient to control perennial sourgrass and consequently decreased their dry weight. The results showed that only one application of graminicides was not effective to control perennial sourgrass at full flowering, being necessary a sequential application (A + B) to efficiently provide the complete control at this growth stage.
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