ABSTRACT
Symptoms and diagnostic features The first symptoms of this disease are angular yellow leaf spots that later develop into irregularly shaped, brown, water-soaked spots with yellow halos (68). These lesions dry out and become brittle. Older lesions sometimes appear black. Lesions develop particularly at the leaf margins. Formation of a gummy exudate and browning of the petioles also occurs. The pathogen can cause lesions and a blight of the flower umbels and flower stalks; a yellow exudate can ooze from such lesions. Bacterial leaf blight symptoms may resemble those of other foliar diseases of carrot such as Alternaria leaf blight and Cercospora leaf blight. Examination by microscope and lab analysis are required to differentiate these various foliar blights.
