Spots turn brown and appear cracked, roughened, and warty. In damp weather, various secondary decay-producing organisms enter through these spots and cause the fruit to rot. Contaminated seed is a common source of first infection so seed should be disinfected with bleach. Bacterial spot also overwinters on residue of infected plants and is spread in the field on machinery. Bacteria can overwinter on debris buried more than 12 inches below the surface but are destroyed on the soil surface or if brought to within 12 inches of the surface.
Plants infected in the seedbed are the primary source of the disease in the field.
Dry weather will usually slow the disease. Prolonged periods of warm, rainy weather, especially when driving rain and wind have broken leaves or stems, are often followed by severe outbreaks. Florida research showed that damage from wind and wind-blown sand, and from splashing during rain storms, increa sed the number of bacterial spot lesions. Windbreaks, such as sugarcane or other tall grasses, planted approximately every 12 rows usually reduce wind damage. These bacterial diseases can cause defoliation and blossom blight in tomato.