Avaliação de tolerância ao herbicida Sequence do clone de eucalipto AEC 144

The cultivation of eucalyptus plays a fundamental role in the Brazilian economy, being widely used in the production of pulp, wood, and biomass. During the early stages of cultivation, competition with weeds can compromise seedling growth, requiring the use of herbicides. This study evaluated the impact of the herbicide Sequence (glyphosate + Smetolachlor) on the growth of the AEC 144 eucalyptus clone and the efficacy of foliar fertilization in mitigating phytotoxic effects. The experiment was conducted in the municipality of São João Evangelista-MG, under a completely randomized design with five herbicide doses (0, ¼, ½,¾, and 1x the recommended dose) and the presence or absence of foliar fertilization, totaling ten treatments. Biometric variables such as height, stem diameter, chlorophyll content (SPAD), and dry mass of roots and shoots were assessed at 60 and 120 days after herbicide application. The results showed that the herbicide significantly (p≤0.05) reduced plant height and stem diameter. The average height of treated plants was 35.1% lower than the control, and the greatest reduction in diameter (16.6%) occurred at the ½ dose. Root dry mass also decreased with increasing herbicide doses. Although no plants died, visible symptoms of intoxication were observed, and partial recovery occurred at 120 days. Foliar fertilization did not mitigate the herbicide’s effects. Chlorophyll content (SPAD) showed no significant variation among treatments. It is concluded that the application of the herbicide Sequence compromised the growth of the AEC 144 eucalyptus clone, reducing height, stem diameter, and root mass. Foliar fertilization was not effective in reducing phytotoxic effects, indicating the need for careful herbicide management to prevent damage to plant development. The AEC 144 eucalyptus clone demonstrated sensitivity to the herbicide Sequence.