Can't tell without a picture, but banana plants are very hungry and thirsty. We have never found they were easy to kill off.

As Wally says, it hard to tell without seeing the plant. They are heavy feeders, and yellowing MAY indicate a lot of conditions. Possible mineral or nitrogen deficiencies, wind damages, improper watering (too much or too little) - all could be the culprit. I have a number of varieties that have red blotches but these are part of their natural coloration. I added a link to the CRFG fruit facts banana page with information on these...

Here is a link that might be useful: CRFG Banana page