P-053 - Development and management of bacterial spot on peach during preharvest period

Bacterial spot is a major disease of peach caused by Xanthomonas arboricola pv. pruni (Xap). Xap develops sunken brown to crater like lesions on the fruit surface and makes them unmarketable. Management of this disease heavily relies on copper and oxytetracycline sprays; however, they are usually not applied during the three-week preharvest period because of the risk of phytotoxicity and residual effect. We surveyed three different peach farms in South Carolina with three different cultivars over three years during 2022 to 2024 to evaluate the disease progression during the preharvest period. Significant increase of bacterial spot incidence and severity were observed on fruit of two susceptible cultivars, but no statistical difference was observed for the tolerant cultivar. The biopesticide spray options were evaluated during the preharvest period to reduce fruit loss. Results will improve our understanding of the disease development during this period and potential options to improve disease control.