Implications of fungicide sensitivity to Pseudocercospora cladosporioides for sustainable management of olive leaf spot

Olive leaf spot, caused by Pseudocercospora cladosporioides, is a major foliar disease of olive crops. This study evaluated the in vitro sensitivity of eighteen Uruguayan isolates to eighteen fungicides from eight chemical groups. Mycelial growth inhibition assays were performed on PDA with increasing fungicide concentrations, and the EC₅。 values were calculated. Copper-based fungicides showed moderate inhibition. Among contact fungicides, mancozeb exhibited the best inhibition compared with ziram and captan. Most systemic fungicides showed the greatest effectiveness, particularly carbendazim, trifloxystrobin, and mefentrifluconazole. These findings provide baseline sensitivity data to support fungicide selection and resistance monitoring for olive leaf spot management diseases.