They have a grayish center with dark brown borders. The disease usually is more or less confined to the upper surface of the leaf. Carefully remove and burn old iris leaves in the fall or early spring. Common leafspot of iris in Central Texas. Remainder of spot is light tan.
Good sanitation is best control.
Removal and burning of old leaves each fall is desirable. This soil fungus enters the roots of bulbous iris and then penetrates the base of the plant and the scales of the bulb. Bulbs should be dried rapidly to avoid possible injury. Cull and discard damaged bulbs. A foul-smelling soft rot of the rhizome.