ABSTRACT.- We produced an extract of Melia azedarach and assessed its potential for managing health problems in Eucalyptus nurseries. We assessed different extraction parameters, looking for maximizing extraction efficiency. The enhanced percolation technique showed an efficient extraction process, facilitated using bioethanol as a solvent at room temperature. We carried out field trials to check the efficacy of the extract. We observed a decreased severity and incidence of powdery mildew after application of the extract, and a reduction in the infestation of B. occidentalis. These results highlight the potential of this extract as a sustainable alternative to chemical biocides. © 2024 Instituto Nacional de Investigación Agropecuaria / Universidad de la República. Published by Informa UK Limited, trading as Taylor & Francis Group.