Hello community sorry my english is not very good but I hope someone can help me with my banana plant. Please look at the pictures I'm happy for every message. I can try to translate it, but the most important is the Diagnose of you :)

The leaves which are older getting Brown powder (eggs?) , Special on the upper side and I see little small white/ beige animals, long time ago my banana plants inside of the apartment had spider mites but i think these are not such. It is a banana plant which should be conditionally winter proof. I would also like to know from you whether I can put it in this size (from 80cm trunk minus the pot that is about 15 cm high. I had to cut off three leaves now it has 2 about 67 cm long) outside ( In the garden in the flower bed(?) ) this autumn and whether you then have to cut them off and cover them or whether it is safer if I try to overwinter them in a pot on the balcony for another year. in an emergency, I would take them in if the temperatures were too clearly in the minus range. my balcony is very sheltered in the corner and always a few degrees warmer than 'outside' , I could also cover it there, if necessary, I would also like to know if I have to cut it short.