Bacterial soft rot causes soft wet decay of the bulbs. Discard rotted bulbs and plant in well drained soil. Avoid wounding plants during the growing season. Dig bulbs carefully to avoid injury. No chemical control is listed.
Gray mold causes circular to oval, yellowish to reddish brown spots. Some spots have light gray centers and dark purple shading to green outer regions. In wet weather the spots run together blighting the whole leaf. Stems break over at the point of infection. Infected flowers and flower buds are abnormal and brown. The growing point may be killed. Bulb scales may still be used for propagation if dusted with sulfur. Gather and destroy infected leaves. The disease is caused by Botrytis cinerea and may be controlled with benomyl.
Foot rot attacks the stems just below soil level. The infected parts shrivel and the plants wither, topple over and die. Only the shoot tip will suffer if plants are infected as the sprout. Dig up and destroy infected plants. Plant the bulbs in well drained soil and avoid wounding. This disease is caused by Phytophthora cactorum. No chemical control is listed.
Frost injury causes a condition called puffy leaf. The plants will be stunted. Mulch to protect young shoots from frost.