It attacks primarily the lower leaves, producing dark brown, circular spots up to one-fourth inch in diameter, the centers of which are light gray, almost white.
Infected leaves dry up and die prematurely.
For control, spray periodically with recommended fungicides and burn infected leaves. White or grayish moldy growth on upper side of older leaves. Leaves gradually die, beginning on the lower part of the plant. For control, spray with recommended fungicides as soon as the mildew appears. Neither rust is important enough to warrant control.