Blue mold is a storage problem and is worse on injured bulbs. The disease is most likely in moist storage conditions. Use benomyl to control this disease caused by Penicillium sp.
Crown rot covers bulbs with layers of coarse white mold. Remove infected plants and avoid infested soil for 2 to 3 years. No chemical control is listed.
Basal rot causes a decay starting at the roots or bases of the scales, and spreads upwards inside the bulb. The plants are dwarfed and the blossoms abnormal. The disease is caused by Fusarium oxysporum and may be controlled with benomyl.
Fire causes spotting and rotting of flowers in humid weather. The disease spreads to, and rapidly destroys, the leaves. The symptoms on leaves are dark reddish, elongated, brown spots. Rake up and destroy old foliage. The causal organism is Sclerotinia polyblastis and no control is listed.
Leaf spot causes large spots or blotches on the leaves. The leaves wither and die. The bulbs lack nourishment due to the premature death of leaves. Remove and destroy plants with diseased foliage. No chemical control is listed.
Smolder rots the foliage and flowers in cold, wet seasons. The leaves are stuck together when they emerge and infected bulbs rot in storage. Remove and destroy infected plants. No chemical control is listed.
Root rot causes leaf yellowing and stunting and withering of plants. The roots have yellowish or brown discolored stripes and decayed regions. The bulbs remain sound. This disease is more of a problem where narcissi have been planted for several years. No chemical control is listed.
Leaf scorch causes blighted leaf tips to be separated from healthy portions by a yellow area. The secondary infection on the lower leaves is minute, watersoaked or yellowish spots, which become raised, scabby and reddish. The flower stalks and flowers may be spotted. No chemical control is listed.