Glyphosate efficacy, absorption and translocation for Eragrostis plana control

Abstract

Background: Glyphosate is the most effective herbicide to control the invasive and perennial Eragrostis plana in Southern Brazil. However, one application has not been sufficient to prevent the regrowth of plants. Objective: The aim of this research was to evaluate the efficacy of glyphosate sprayed alone or mixed with fluazifop-p-butyl or flumioxazin on E. plana control and to investigate14C-glyphosate absorption and translocation. Methods: Plants with 2-3 tillers were treated with glyphosate (700 g a.e. ha-1), fluazifop-p-butyl (47 g a.i. ha-1), flumioxazin (100 g a.i. ha-1), glyphosate + fluazifop-p-butyl (700 g a.e. ha-1 + 47g a.i. ha-1), glyphosate + flumioxazin (700 g a.e. ha-1 +100 g a.i. ha-1). Weed control was evaluated visually for 28 d after treatment (DAT) when plants were harvested for shoot dry biomass determination.14C-glyphosate absorption and translocation were measured at 24 and 72 h after treatment. Results: Glyphosate at 700 g a.e. ha-1 controlled E. plana plants at 2-3 tillers. The mixture with fluazifop-p-butyl or flumizin did not significantly increase the level of control (87 and 86% at 7 DAT, respectively) but increased14C-glyphosate translocation to the roots. Conclusions: Glyphosate is effective on E. plana. However, applied with fluazifop-p-butyl could improve the control of this weed, especially when perennial plants of E. plana dominate the field, preventing their fast regrowth.