The fungus botrytis tulipae causes this common disease of tulips. Leaves and flowers will have light to dark colored spots, which enlarge to form gray blotches that will eventually cover the entire area. In cool, moist weather the infected tissue develops a fuzzy brown or gray mold. Stems and leaves may become distorted and rot off the bases.
Bulbs have dark, circular, sunken lesions or dark brown pin-sized pellets on their husks.
The fungi enters the plants through wounded, weak or dead plant tissues in periods of cool, moist weather. The fungi persist through the winter and survive hot, dry periods as the tiny pellets in soil. These pellets then produce spores, which attack flowers and foliage again in the spring. Fungi are spread by splashing water. Before planting bulbs, check for signs of infection and discard bad bulbs.