The initial symptoms on the leaves are small, shapeless, oily spots. As the disease progresses, these spots merge, leading to the drying of the entire leaves. Similar oily-looking spots appear on the leaf petiole, stem, and fruit peduncle. In fruits, small initially, gradually enlarging, slightly concave spots with a tendency to crack in the center develop, eventually causing complete decay of the fruit. When the disease affects tomato plants during the flowering stage, significant plant losses can occur. It is essential to use clean, disease-free seeds. Plants showing signs of the disease during the seedling stage should be removed and destroyed. Greenhouses should be ventilated regularly. Crop rotation of 2-3 years is recommended in greenhouses where the disease is present. Disease control can be achieved through chemical intervention.

The bacterium causing the disease can be transmitted through seeds. The bacteria present in the seeds pass directly into the vascular bundles and spread throughout the plant. As tomato plants approach the flowering stage, fading begins on the lower leaves, progressing upward over time. The typical symptoms of the disease include fading on one side of the plant, and the affected leaves eventually dry out. When a plant showing symptoms of wilting is cut in the middle, a subtle yellowish, light brown discoloration is observed along the vascular bundles. In advanced stages of the disease, wounds and cracks develop in the tomato stem, earning the disease the name “bacterial canker.” In fruits, lesions are characterized by a central light brown area surrounded by a white halo, referred to as a bird’s eye pattern. Infected plants should be uprooted and destroyed. Greenhouses should be ventilated regularly, and when pruning tomatoes in greenhouses, plants showing signs of the disease should be left for the last. Crop rotation of 2 years can be implemented in greenhouses where the disease is present.

Low night temperatures and high relative humidity encourage the development of the disease. A combination of wilting and yellowing is observed, particularly on the upper leaves. Brown-black spots develop, especially in the leaf axils on the stem. When the stem, leaf, and fruit petioles are cut lengthwise, a brown-black color is evident in the vascular tissue. As the disease progresses, the vascular tissue disintegrates and becomes empty. Infected plants generally remain standing, but sometimes wilting and death occur. Excessive nitrogen fertilization should be avoided, and plants should be nourished in a balanced manner. Infected plants should be removed from the greenhouse. Care should be taken not to injure plants during maintenance procedures, and when pruning in greenhouses, diseased plants should be pruned last.

Primary infection can begin either from bacteria present on the surface of seeds or through contact with diseased plant residues in the soil. Secondary infections occur through wounds or natural openings in the plant. The pathogen spreads through raindrops or overhead irrigation. The disease exhibits increased activity in cool and humid weather, while development halts in hot weather. The pathogen creates lesions on leaves, stems, flower, and fruit peduncles ranging in color from brown to black. Initially, the leaf lesions are small, round, and dark. Lesions also appear on the main stem and associated branches, as well as on leaf and flower peduncles. The lesions are typically elongated and superficial. If the disease occurs, especially on the first flowers, it can significantly impact fruit setting, leading to substantial crop loss. Lesions on fruits can cause deformities, reducing the commercial value of tomatoes. Plants showing symptoms during the seedling stage should be destroyed. Proper ventilation and prevention of excessive humidity accumulation should be ensured in greenhouses.