Bacterial speck is caused by the bacterium Pseudomonas syringae pv. tomato and it only affects tomato. Small black specks appear on the leaves, stems, and fruits. The development is favored by relatively cool wet conditions. Spots appear on young green fruits on slightly raised areas. The lesions do not crack or become scaly. The disease-causing organism may overwinter in seeds, other weedy hosts, crop residues, and in soil.

Commercial - rotate tomatoes with other vegetables; plant disease-free certified seeds or transplants; and plant resistant varieties. Avoid walking in the garden when the leaves are wet.