The top one looks like Gibberella ear rot. 

Could also be Fusarium or Diplodia ear rot. 

Might Google any of the 3 for more info. 

Found pictures of those ear rots in Modern Corn Production by Samuel R. Aldrich, Walter O. Scott and Earl R. Leng. Second Edition 1975 by A & L Publications.  Library of Congress Number 75-13504.

I have had all 3 during my years of seed corn production. 

I could keep it clean with 3-4 applications of fungicides per year.