Bacterial soft rot causes the stem to rot near the soil level. The corm becomes infected, the leaves are blighted, and the entire plant wilts and dies. Discard infected plants.
Crown rot is the soft decay of the lower half of the main corm and the thicker feeder roots.
Several leaf spots cause spotting of the leaves.
Root rot symptoms appear on the lower outer leaves about the time the plants begin to flower. The leaves become streaked with yellow, wilt, turn brown and die. Any flowers which open are likely to be poorly formed and turn brown at the tip.