Bacterial spotCaused by: Xanthomonas campestris pv. vesicatoria
Problem Category: Bacterial Disease
Symptoms: Bacterial spot lesions starts out as small water-soaked spots; lesions become more numerous and coalesce to form necrotic areas on the leaves giving them a blighted appearance; of leaves drop from the plant severe defoliation can occur leaving the fruit susceptible to sunscald; mature spots have a greasy appearance and may appear transparent when held up to light; centers of lesions dry up and fall out of the leaf; blighted leaves often remain attached to the plant and give it a blighted appearance; fruit infections start as a slightly raised blister; lesions may have a faint halo which eventually disappears; lesions on fruit may have a raised margin and sunken center which gives the fruit a scabby appearance.
Comments: Bacteria survive on crop debris; disease emergence favored by warm temperatures and wet weather; symptoms are very similar to other tomato diseases but only bacterial spot will cause a cut leaf to ooze bacterial exudate; the disease is spread by infected seed, wind-driven rain, diseased transplants, or infested soil; bacteria enter the plant through any natural openings on the leaves or any openings caused by injury to the leaves.
Management: Use only certified seed and healthy transplants; remove all crop debris from planting area; do not use sprinkler irrigation, instead water from base of plant; rotate crops.