Publicação on-line; 28 ref.; 9 tables; Summary (En)

ABSTRACT
Background: Knowledge about the action of glyphosate alone and
associated with adjuvants in the effectiveness to control aquatic plants is
important in the decision-making on its use.
Objective: This study aimed to evaluate the effectiveness of glyphosate
and five adjuvants in the control of Myriophyllum aquaticum.
Methods: Glyphosate (Rodeo®) at doses of 1.5, 3.5, 5.5, and 7.5 L ha-1
was sprayed alone and associated with Aterbane® BR, Veget’oil®, Dash®
HC, Assist®, and Agral® (0.5% v v-1), in addition to the control, with a
spray solution volume of 200 L ha-1. The effectiveness of control was
evaluated using the scores of a visual scale at 3, 7, 15, 21, 30, 45, and
60 days after application (DAA), regrowth, and dry matter accumulation
at 60 DAA.
Results: The best effectiveness of control of the glyphosate alone was
85% at the dose of 7.5 L ha-1, increasing to 100% when associated with
Aterbane® and Veget’oil®. The control reached 100% for all glyphosate
doses associated with Dash®. Moreover, glyphosate at the dose of
7.5 L ha-1 associated with Assist® provided a 98% control, while
glyphosate doses of 3.5, 5.5, and 7.5 L ha-1 associated with Agral®
provided a 100% control. Glyphosate at doses of 5.5 and 7.5 L ha-1
associated with Dash® and Agral® was more effective in reducing the
regrowth and dry biomass (100%). Thus, glyphosate + Dash® and Agral®
promoted the highest control (above 95%), the lowest regrowth, and the
highest reduction in the dry biomass of M. aquaticum.
Conclusions: The addition of Aterbane® BR, Dash®, and Agral® to
glyphosate improved the effectiveness of control of M. aquaticum and
contributed to reducing the applied herbicide dose.

Keywords:
chemical management
parrot feather watermilfoil
aquatic plants