Larger leaf blotches may also occur, especially on the margins of leaves. Symptoms on immature fruit are at first slightly sunken and surrounded by a water-soaked halo, which soon disappears. The bacterium is seedborne and can occur within the seed and on the seed surface. The pathogen is spread with the seed or on transplants. Secondary spread within a field occurs by splashing water from sprinkler irrigation or rain.
Infection is favored by high relative humidity and free moisture on the plant.
Some pathogen strains are virulent on either tomato or pepper and some may be virulent on both. Avoiding sprinkler irrigation and cull piles near greenhouse or field operations, and rotating with a nonhost crop also provide satisfactory control. Copper is strictly a protectant and must be applied before an infection period occurs. The addition of mancozeb increases the efficacy of copper. Check with your processor concerning allowed materials and rates.