Bacterial blight infections can affect any above-ground portions of the plant and at any point of plant development. Lesions associated with Xanthamonas begin as an angular leaf spot with a red to brown border.

Tissues surrounding lesions may also become yellow, giving the appearance of a "halo" surrounding the lesion. The angular appearance of lesions is due to restriction of the lesion by fine veins of the cotton leaf, and bacteria may spread along the leaf veins causing blackened lesions along major veins. Leaf petioles and stems may also become infected (cotton black leg).

which can lead to premature defoliation of the plant. Black cankers on stems or branches may girdle the plant causing the portions to die above the canker. Additionally, a white waxy crust containing the bacterium may also form on old leaf spots or cankers.

Infected bolls have round, as opposed to angular, lesions that initially may appear water-soaked, and then become sunken and dark brown to black. Bolls infected with Xanthamonas may result in rotted seed and discolored lint.