Pathogen(s) causing disease: Colletotrichum graminicola
Symptoms: Water-soaked areas on the surface of the lower internodes, developing brownish linear streaks, turning black later in the season, larger oval black areas may develop, disintegrated gray to dark brown pith, severely infected stalks likely to lodge.
Conditions: Favored by cool to warm, wet, humid weather, minimum tillage, continuous corn, environmental stresses that result in early senescence.
Management: Resistant hybrids (full season hybrids tend to have more resistance than short season), two year crop rotation with nongrass crops, cleanly plow under infected residue, balanced soil fertility, reduce plant stress and control corn borer.
Sources:
Purdue University
University of Illinois