Bacterial canker of tomato
"There are usually no symptoms of bacterial canker on seedlings; however, on young plants symptoms consist of poor growth and temporary wilting of branches. Lower leaves yellow and shrivel, but symptoms may not show until flowering. On mature plants there are two kinds of symptoms, those resulting from systemic infections (i.e., the bacteria enter the vasculature and invade much of the plant) and those resulting from secondary infections (i.e., the bacteria cause local infections of leaves, stem, and fruit).In systemic infections of mature plants, leaflets of the oldest leaves curl, yellow, wilt, and finally turn brown and collapse (known as firing). Sometimes, one side of a leaf is affected. Plants grow poorly and wilt. Pith of stems becomes yellow and later reddish brown, especially at the nodes, and has a mealy appearance. The pith may later become somewhat hollow. In advanced infections, cankers may or may not form at the nodes. Light and later dark streaks may develop on stems. Branches break off easily. Plants may die.In secondary infections, infection of the margins of leaves is common. Lesions are dark brown to almost black. Round to irregular spotting of leaves also occurs. Fruit may be spotted, especially near calyx. On fruit bacterial canker symptoms appear as yellow to brown spots, slightly raised, surrounded by a persistent white halo (""bird's eye spot""). Spots are usually about 0.125 inch (3 mm) in diameter. Vascular tissue under the calyx scar and leading to seeds that may be brown."