The spots are mostly superficial, but numerous infections can cause pitting and cracking of the fruit surface. The fruit cracks may show gumming. The bacterium overwinters in small, blister-like cankers on the twigs. In early spring, the cankers rupture and release millions of bacteria. These bacteria are dispersed by splashing water and infect developing leaves and fruit.
Infection is favored by frequent rainfall accompanied by high winds and moderate temperatures.
Extended periods of hot, dry weather inhibit disease development. Peach cultivars vary in their susceptibility to bacterial spot, although no variety is immune. Those cultivars showing tolerance to the disease include Redskin, Redhaven, Loring, Candor, Biscoe, Dixired, Sunhaven, Jefferson, and Madison. Most apricot and nectarine cultivars are susceptible to bacterial spot. Excessive fertilization can predispose peaches to severe bacterial spot infections.