Document Type : Original Article

Authors

• Gizelly Santos
• Henrique Fabrício Placido
• Luiz Augusto Inojosa Ferreira
• Jamil Constantin
• Rubem Silvério de Oliveira Jr.

State University of Maringá, Departament of Agronomy, Av. Colombo, 5790 - Vila Esperanca, Maringá - PR, CEP: 87020-270, Brazil.

Abstract

The objective of this work was to evaluate the selectivity of herbicides applied in post-emergence of mulato II grass, in different stages of forage development, in areas with in-row and broadcast seeding. In order to understand the influence of the time of application of the herbicides on the selectivity of mulato II grass, two experiments were designed: the first with application of treatments 15 days after emergence (DAE) and the second to 45 DAE. The experiments were installed in two areas, one with broadcast seeding and the other with in-row seeding. For all experiments, 5 herbicides were applied in two doses, in the double control system: [aminopyralide+fluroxipyr] 1.0 and 1.5 L ha^-1, [2,4D+picloran] 1.5 and 3.0 L ha^-1, [aminopyralide+2,4-D] 1.0 and 2.0 L ha^-1, [aminopyralide+metsulfuron] 0.075 and 0.150 kg ha^-1 and [aminocyclopyrachlor+metsulfuron] 0.075 and 0.150 kg ha^-1. For applications performed at 15 DAE only [aminocyclopyrachlor+metsulfuron] was not selective in both tested sowing systems. For applications performed at 45 DAE in-row seeding, the treatments [aminocyclopyrachlor+metsulfuron] in the two tested doses and [aminopyralide+metsulfuron] in the highest dose caused injuries to mulato II grass. For applications carried out at 45 DAE in a field sown by broadcast seeding, only [aminocyclopyrachlor+metsulfuron] caused injury to the culture. At all times of application, the herbicides [aminopyralide+fluroxipyr], [2,4-D+picloram] and [aminopyralide+2,4-D] in the two doses tested, proved to be selective for the fields sown by broadcast and in-row. In the second productive cycle, there was no negative effect of treatments in the four experiments.

Keywords

• Application stage
• Brachiaria
• Broadcast seeding
• Grazing simulation
• In-row seeding