Water-soaked spots on leaves which are delimited by leaf veins giving them an angular appearance; lesions increase in size and turn black and necrotic; leaves drop from plant; disease may also cause elongated gray-black lesions extending from the leaves to petioles and stem which are known as the \"black arm\" phase; severe black arm symptoms may cause the stem to be girdled; water-soaked lesions may be present on bolls; boll lesions enlarge and become sunken and brown-black in color.