Stemphylium vesicarium is the causal agent of Brown Spot of Pear (BSP), producing high economical losses in several pear-growing areas in Europe. In Italy, BSP control in field can also rely on the use of SDHI (Succinate Dehydrogenase Inhibitor) compounds such as boscalid, penthiopyrad, fluopyram and fluxapyroxad. Efficacy field tests on these fungicides sprayed as solo product were conducted during 2016 and 2017 in a pear experimental orchard located in the Emilia-Romagna region. All the fungal strains isolated in both years from the plots were tested for their in vitro sensitivity to SDHI fungicides already authorized in Italy against BSP, together to bixafen and isopyrazam. Overall, the results highlighted the onset of problems related to the efficacy of SDHIs. These observations were mirrored in EC50 values showed by the strains collected in both the years. Molecular analysis carried out in the laboratory, led to discover amminoacidic substitutions conferring SDHIs resistance in the S. vesicarium of pear.