Ergot of rye is caused by a species of:

Ergot of Rye is a plant disease that is caused by the fungus Claviceps purpurea. The so-called ergot that replaces the grain of the rye is a dark, purplish sclerotium, from which the sexual stage, of the life cycle will form after over wintering. Corn smut is caused by the fungus Ustilago maydis. Powdery mildew of grapes is caused by fungus Uncinula necator. Root and stem rot is caused by Phytophthora sojae.