ORIGINAL ABSTRACT

It is proposed that the herbicide terbuthylazine is more effective than atrazine in controlling weeds in maize. This study aimed to evaluate the efficacy of terbuthylazine and atrazine in a mixture with glyphosate in glyphosate-tolerant maize for post-emergence application. The experiment was conducted over three trials using randomized blocks with 4 repetitions and 10 treatments, composed by terbuthylazine rates + glyphosate, atrazine rates + glyphosate, [atrazine + mesotrione] + glyphosate, atrazine + tembotrione, isolated glyphosate, and nontreated control. Trial 1 were infested with Bidens subalternans DC. and Commelina benghalensis L; trial 2 with Urochloa plantaginea (Link) R. D. Webster, Ipomoea spp., volunteer soybean, B. subalternans, and grasses; and trial 3 infestation with C. benghalensis, U. plantaginea, Ipomoea spp., volunteer soybean, B. subalternans, Amaranthus hybridus L., and grasses. Weed control, crop injury, and yield were evaluated. Terbuthylazine + glyphosate showed an efficacy equivalent to that of atrazine or [atrazine + mesotrione] + glyphosate in the control of broadleaves and C. benghalensis. In contrast, the efficacy of terbuthylazine was similar or greater than that observed for atrazine in controlling grasses, depending on the location. Terbuthylazine is an important partner of glyphosate in controlling weeds in maize and is an alternative to atrazine.