Weed Control J 2025; 24: e202500872

ISSUE Cover

Herbicide associations applied post-emergence to control smutgrass (Sporobolus indicus) in cultivated pasture

DOI: 10.7824/wcj.2025;24:00872

Abstract:

Background:

Among the weed species causing the most significant losses to livestock farming is smutgrass (Sporobolus indicus), due to the high aggressiveness this weed exhibits when coexisting with pastures.

Objective:

To evaluate the effectiveness of mesotrione isolated and in association with FSII inhibitors herbicides in the post-emergence control of smutgrass infesting pasture cultivated with Brachiaria humidicola.

Methods:

The experiment was conducted in the field using a randomized complete block design, evaluating nine treatments with four replications. The treatments consisted of post-emergence application of mesotrione alone and in combination with FSII inhibitors (atrazine and terbuthylazine), varying the proportions of herbicide doses, as well as commercially formulated mixtures or tank-mixed combinations. At the time of treatment application, smutgrass plants were in the reproductive stage (flowering), and the pasture was in full vegetative growth.

Results:

Regardless of the dose (125 or 150 g ha^-1), the use of mesotrione alone was not sufficient to control smutgrass. The combination of atrazine with mesotrione, either as a commercially formulated mixture or tank-mixed, improved the control of smutgrass. The performances of atrazine + mesotrione (commercially formulated mixture) and terbuthylazine + mesotrione (tank-mixed), regardless of the doses, were similar in controlling smutgrass, making them the best alternatives. All treatments caused low levels of phytotoxicity in Brachiaria humidicola.

Conclusions:

Associations between mesotrione and FSII inhibitors (herbicides atrazine or terbuthylazine) herbicides have potential to control smutgrass, being selective for pasture cultivated with B. humidicola.