The infected ovary appears dull green and smaller or larger than the healthy, fertilized ovary which is dark green and round. Superficial, white mycelial growth initially appears at the basal end of the ovary and extends upward as the pathogen colonizes ovary tissues both internally and externally. Finally, the complete ovary is converted into a white, fungal mass, or sphacelium, that is visible between the glumes. Honeydew exudation then begins. Newly formed honeydew droplets are colorless and transparent, and become progressively opaque.
Honeydew can be uniformly yellow-brown to pink, or superficially matt white.
Continued production of honeydew causes droplets to lengthen, smearing seeds and leaves, and falling to the ground. When infection is severe, affected panicles can be recognized from a distance. They may be white with fresh honeydew, or black if the honeydew is saprophytically colonized. This white growth covers the surface of the honeydew wherever it is present including the panicle, leaves, and soil. If moist conditions persist, several saprophytes grow on the honeydew.