Abstract
Cercospora medicaginis is a widespread fungal pathogen that reduces yields and forage quality of annual and perennial Medicago species. The lack of studies on this pathogen has prompted us to characterize the morphology in culture and the aggressiveness of seven C. medicaginis isolates infecting annual Medicago species in different geographic area in Tunisia. The morphology of the C. medicaginis cultures on wheat bran juice-based agar medium vary in color and surface relief between the isolates. The C. medicaginis isolates exhibited different growth and sporulation rates on synthetic medium and they showed different conidia dimensions. The inoculation tests of C. medicaginis isolates on Medicago truncatula detached leaflets (F83005.5 line) showed a clear difference in aggressiveness between them. Correlation analysis showed that aggressiveness of C. medicaginis isolates was associated to a higher growth and sporulation on synthetic medium.