•High-affinity monoclonal antibodies to boscalid are described.•Antibodies specific for boscalid and its metabolite were generated.•Two competitive ELISA were validated for boscalid determination in strawberries.•Occurrence of boscalid in commercial strawberry samples was 15%. Boscalid is an agrochemical recently developed for crop protection and the most significant member of the succinate dehydrogenase inhibitor group of fungicides. In this study, a collection of high-affinity monoclonal antibodies was generated to boscalid. By using a series of haptens with a linker at alternative tethering sites of the boscalid framework, specific antibodies were isolated as well as antibodies that also recognized the main boscalid metabolite. Two immunoassays were developed using different ELISA formats. Optimized assays displayed very high sensitivities (limits of detection were near 0.01µg/L). Trueness and precision for the determination of the target analyte in strawberry samples was evaluated. Moreover, immunoassay performance was validated with a reference chromatographic method using QuEChERS extracts of fruits from fungicide-treated crops. A monitoring study with strawberry samples from local markets was carried out by immunoassay, showing an occurrence of boscalid of 15% with a maximum residue concentration of 43µg/kg.