Pierce’s Disease (PD) is a major disease of grapevines in the southeast US caused by the xylem dwelling bacteria Xylella fastidiosa subsp. fastidiosa (Xf). XylPhi-PD is a bacteriophage product recently registered for PD management in grapevines in Georgia. In 2023 and 2024, ‘Vidal blanc’ hybrid winegrape vines with a history of PD were either ‘treated’ at the maximum label rate or ’untreated’ in a commercial vineyard in Lumpkin Co. GA. Disease was rated visually by two raters in September shortly after harvest. A subsample (n=80) was assessed by AmplifyRP XRT to confirm visual assessment. Overall, there was a reduced disease incidence and severity in the treated vines for both years (chi-sq p
