Bunt,
attacks the ears of wheat, completely filling the grains with a black, fetid powder. This powder is a mass of spherical, reticulated spores, which, when crushed, give out a most disagreeable smell. It was formerly called stinking rust. Bread made from flour containing this fungus has a disagreeable flavor and a dark color. Such flour, however, is said to be sometimes used in the manufacture of gingerbread, the molasses effectually disguising the flavor. The presence of bunt is readily detected by the microscope.
Entry from Everybody's Cyclopedia, 1912.