On leaves of more mature plants, the pathogen can cause large, circular brown lesions, usually near the edge of the leaf, but this is not reliable for diagnosis. The unique symptoms are: irregular, rust-colored lesions that run along leaf ribs (Image 1),
while on the underside of the leaf, the leaf rib is water-soaked (Image 2)
Leaf lesions can serve as a source of bacteria that can infect fruit. In the field, leaf lesions are often difficult to find and may be confused with lesions caused by pathogenic fungi.