Hate to even say it but I just looked through an old post of PR Giants, "Links to Help Identify Your Banana" today that someone resurrected and at the bottom of post No. 11 of the thread there is a photo of something called "Banana Streak Virus" and "Cucumber Mosaic Virus". Might want to check those out or ask Gabe about it. I hope these are not applicable to your plant.
Links To Help Identify Your Banana