(Xanthomonas arboricola pv. pruni (Smith) Vauterin et al.
Distribution: Most common in warm and wet climates; tends to be a greater problem in orchards with a history of disease. It is one of the most serious diseases in southeastern US peach production.
On leaves, lesions are small, tan to brown in color, eventually becoming necrotic, and usually surrounded by a yellow halo. There are often numerous lesions on a leaf and they tend to be restricted to areas between veins, which gives them an angular appearance. Lesions are eventually walled off and the center of the lesion drops out, giving the leaf a tattered or shot hole appearance (A). Severe foliar infections results in the yellowing of leaves and premature leaf drop. Bacteria from leaf infections move to the current year's twig growth, leading to canker formation. On fruit, the bacteria cause dark brown lesions or blemishes. Lesions often become sunken and the skin of the fruit cracks, causing deep pits that leave the fruit unmarketable (B, C).