“Blue Eye” Mold – Penicillium and Aspergillus Kernel Rots

Source: USDA FGIS/Education and Outreach Visual Reference Library

Source: USDA FGIS/Education and Outreach Visual Reference Library


Fungi may enter kernels through uninjured pericarps even at moisture content as low as 14%. The fungi grow in the germ (embryo) and sporulate beneath the pericarp covering the germ area and giving this area a blue – green color. These fungi invade individual or groups of kernels; affected kernels may be at tip or scattered over the ear.



Kernel infection by certain species of Aspergillus and Penicillin, cause damage to corn under poor storage conditions.



Penicillium and Aspergillus kernel rots are associated with mycotoxins.

The rots may develop on either ear or shelled corn in storage, causing major losses in feed and market value. These kernel rots are ordinarily of minor importance in a field before harvest. Kernel rot fungi are more likely to invade kernels damaged by insects and birds.

According to the Federal Grain Inspection Service, the outward appearance of kernels with blue eye mold damage is similar to a condition known as purple plumule. Purple plumule (light to dark purple discoloration) is due to a genetic or varietal characteristic and is restricted to the plumule area (center of germ).  Consequently, it may be necessary to gently lift/remove the germ cover to make an accurate determination.

Grain with evidence of Aspergillus or Penicillium kernel rot should be dried to 14 percent moisture before storage and maintained at this level until used.



Anonymous. 2011. Blue-eyed mold damage. USDA FGIS/Education and Outreach Visual Reference Library – Corn. Available at http://www.gipsa.usda.gov/vri/corn_1.aspx [URL verified 3/28/2019].


White, Donald G. (ed.). 1999. Compendium of Corn Diseases (3rd Edition). APS Press, The American Phytopathological Society.