is one of the most aggressive fungal pathogens of species involved in the decline of Mediterranean oak forests. In this study, three strains of associated with holm () and cork () oak trees exhibiting dieback symptoms and cankers in Algeria were selected to investigate the production of secondary metabolites. Metabolomic analyses revealed the production of several known compounds, such as sphaeropsidins, diplopyrones and diplofuranones. Moreover, the comparative investigation of secondary metabolites produced by the analyzed strains with different degrees of virulence revealed possible implications of these compounds in the fungal virulence. In particular, sphaeropsidins seem to be the main phytotoxic compounds of involved in the infections of species, with a possible synergistic influence of the less representative compounds in the fungal virulence.