Fusarium ear rot is sometimes characterized by pinkish or grayish discoloration of the caps of individual kernels or groups of kernels scattered over the ear or a pinkish mold growth. Another symptom of this ear rot is light-colored streaks radiating from top of kernels where silks were attached – in the pictures above blue corn kernels exhibit these starburst symptoms.
Fusarium ear rot is caused by Fusarium fungi that survive in soil on crop residues. Infection may occur from late vegetative stages to three weeks after midsilk. It is more common in the southern half of Ohio and appears to be associated with continuous corn and reduced tillage. Wet, warm weather following silking by 2 to 3 weeks and damage to kernels by insects, hail, and other mechanical means favors Fusarium kernel rot. Infection from wind-borne spores usually follows injury to ear from corn borer, ear worm, birds, etc. This kernel rot is associated with the mycotoxin, Fumonisin.
Planting resistant hybrids is the most effective way to control Fusarium kernel rot. Some plant pathologist recommend selecting hybrids with ears that dry in declined position and those well covered with husks. Control of insects that damage kernels reduces severity of the disease. Bt hybrids may limit injury by preventing injury of corn borer that create entry points for fungal infection. Crop rotation and fall tillage can reduce the occurrence of the disease by reducing fungal levels in the field.
Lipps, P. E., A. E. Dorrance, and Dennis Mills. 2004. Corn Disease Management in Ohio Bulletin 802.
Vincelli, P. 2013. GMOs and Corn Mycotoxins. Grain Crops Update. University of Kentucky. Available at http://graincrops.blogspot.com/2013/08/gmos-and-corn-mycotoxins.html [URL verified 1/16/2019].