Stalk causein mold?

[Boboro]

The mold Ive had this year was on a stalk that was all or partially black-greenish and kinda slimy. Like it died 1st. This was takein after the stalk had dryed some.

 

[DGBAMA]

I had a single leaf do that on one of my ytb. Main rib turned slimy and soft on the growing plant. It was removed promptly and no further problems. Closest symptom i could find indicated "barn rot" I