Although this symptom damages the appearance of the fruit, it does not destroy the fruit's edibility. However, the resultant cracking may provide suitable sights for ingress of decay fungi. Late season infections are superficial and give the fruit a mottled appearance. Infections of twigs produce cankers from spring to fall. At first the cankers are purplish water-soaked spots, but later become more or less circular to elliptical in shape and sunken.
Cankers allow the bacterium to overwinter.
On plum and apricot, bacteria may survive in cankers for more than one season. The conditions which favor disease development include warm, moderate temperatures, frequent light rains, heavy dew, and considerable winds. If all, or most, of these conditions prevail, severe infection can be expected. When weather favors it,infection by the bacteria may occur anytime from shuck split until post-harvest. Hard, driving rains are more important in starting new infections, thus the disease can be proportionally more severe on one side of the tree than the other.