Palestrante: Dr. Wayne Jurick. Data: 23/04/2019, às 16:00 horas no Anfiteatro do ESB. Blue mold of apple is a globally important postharvest disease caused by Penicillium expansum and other Penicillium spp. The fungus not only causes decay during storage, but also produces the carcinogenic mycotoxin, patulin. There are 4 postharvest fungicides used to control blue mold. Unfortunately, P. expansum has developed resistance to 3 of the currently labeled materials which have manifested in control failures during storage. Hence, new research using both fundamental and applied approaches are needed to investigate pathogen virulence and evaluate new chemistries for control. Our molecular research has uncovered a host of new genes in the fungus involved in the decay process and are the subject of ongoing investigation using functional genetic tools. These genes and their encoded products are envisioned to be the targets of future control points that can be exploited to halt blue mold development. Our applied research has shown that one of the active ingredients (difenoconazole) in a new postharvest fungicide, Academy, is efficacious and baseline sensitivity to a diverse collection of Penicillium spp. has been determined. Based on the mean Estimated Concentration to inhibit 50% growth (EC₅₀) for the collection, we propose screening shifts in sensitivity using 5ppm difenoconazole. Additionally, formulated Academy at the labeled rate can control blue mold decay in apple caused by thiabendazole, pyrimethanil and thiabendazole+pyrimethanil-resistant blue mold isolates under cold storage conditions. Taken together, our fundamental and applied research results have impacted the apple industry both short and long term to develop new targets for control, providing tools to monitor fungicide resistance, and offering science-based options to control postharvest fungicide-resistant blue mold isolates.