Tulip Blight Plant Pathology Tulip Blight Botrytis blight, also called tulip fire, is the most common disease problem on tulip. Damp, overcast weather favors the growth of the causal fungus, Botrytis tulipae . This fungus commonly attacks tulips that have been damaged by frost or hail. All parts of the plant may be infected.
Leaves show small, slightly sunken oval spots that usually have a dark margin.
With moist conditions, these spots may enlarge and coalesce, sometimes involving entire leaves. Stems may rot off completely. Flower lesions also appear as small oval spots that are light in color. The entire flower may eventually become blighted. The outer scales of the bulb develop blackish fungal structures called sclerotia.