Castro, Edicarlos Batista de creator Carbonari, Caio Antonio creator Velini, Edivaldo Domingues creator Macedo, Gabrielle de Castro creator Simões, Plínio Saulo creator text periodical abstract or summary bl. continuing eng ABSTRACT The objective of this article was to evaluate the effects of glyphosate on the initial development of eucalyptus (Eucalyptus urograndis) after its application on brachiaria (signal) grass plants (Brachiaria decumbens). The experiment was conducted in a greenhouse in a completely randomized design. Glyphosate, aminomethylphosphonic acid (AMPA) and shikimic acid concentrations were determined, along with an intoxication evaluation of the eucalyptus plant pointers and dry mass of the plants. Glyphosate was detected in eucalyptus plants after its application on B. decumbens plants, but the eucalyptus plants only presented low intoxication levels in the pointer’s leaves. No AMPA was detected in eucalyptus leaves, and only a dose of 1,440 g e.a. ha-1 of glyphosate reduced the total dry mass of eucalyptus plants. Glyphosate has the potential to cause intoxication in the crop when applied to adjacent plants. Keywords: absorption, Brachiaria decumbens, Eucalyptus urograndis, herbicide, interference. Publicação on-line; 27 ref.; 2 tables; 2 illus.; Summary (En) BRACHIARIA DECUMBENS EUCALIPTO HERBICIDA Rio de Janeiro-RJ Instituto de Florestas - UFRRJ 1994 2025-0452 1415-0980 / ISSN 2179-8087 0nline BR2026001187 v. 26(4) p. 1-7; (2019) https://www.scielo.br/j/floram/a/Rjd7GkjCqNMMqJS6cLVDqSN/?format=pdf&lang=en https://www.scielo.br/j/floram/a/Rjd7GkjCqNMMqJS6cLVDqSN/?format=pdf&lang=en BR-BrBNA 260416 20260416152611.0 eng