AbstractCherry blossoms inoculated with a rifampicin‐resistant strain ofPseudomonas syringaepv.morsprunorumdied or gave rise to fruits containing necrotic spots at or near the blossom ends. Scanning electron microscopy of developing fruits indicated that the pathogen had invaded the entire pericarp, including the endocarp. Bacteria also spread to the fruit stalk and, to a lesser extent, to the spurs. Mesocarp cells below the lesion collapsed. Infected fruit, stalks, and spurs contained, respectively,ca.109, 107, and 102colony forming units ofP. syringaepv.morsprunorumas determined by a dilution plate method on an agar medium supplemented with 50 μg/ml rifampicin. This is the first report of systemic spread ofP. syringaefrom blossoms to developing fruit of a deciduous cr