MANEJO PARA DESINFESTAÇÃO DE CAPIM-AMARGOSO (Digitaria insularis) EM MILHO SAFRINHA COM USO DE HERBICIDAS PRÉ-EMERGENTES

Abstract

Sourgrass (Digitaria insularis) is a highly aggressive perennial plant that has the ability to emerge and develop throughout the year. The existence of glyfosate resistant biotypes make it difficult to manage and control this species in the crop and safrinha maize (Zea mays) due to its physiology and limitation of chemical control based on ACCase (Acetyl CoA carboxylase) inhibitors in post-emergence of the culture. The present work was conducted in a commercial production area under resistant and perennial natural infestation conditions. The experimental design was randomized blocks with four replications. Pre and post-emergent herbicides of recognized agronomic efficiency in difficult-to-control corn crop plants (Atrazine, Glyphosate, S-Metolachlor and Trifluralin) were applied shortly after conventional tillage due to the size and rooting of bitter grass. The symptoms of intoxication and the control efficacy from the natural seed bank of the area were evaluated. The herbicides S-Metolachlor, Trifluralina in pre-emergence applied did not differ from each other presenting excellent control for sourgrass. The herbicide S-Metolachlor, despite recognized graminicide action, not recommended for the control of sourgrass in corn crop.