Question: Could someone help me find what kind of illness is that and how to treat it?

[![Bottom](https://i.stack.imgur.com/kVKNL.jpg)](https://i.stack.imgur.com/kVKNL.jpg)
[![Tree](https://i.stack.imgur.com/NX3wz.jpg)](https://i.stack.imgur.com/NX3wz.jpg)

Answer: 
Looks like it might be oedema caused by waterlogged roots. It occurs when roots take up more water than the plant can use or evaporate away through pores on its leaves. It may be very humid out or the water too warm. Make sure you wait until the soil is at least dry-ish before watering and that you have drainage holes on your container.

I would also double check your fertilizer and how often you're using it. Too much fertilizer can cause this as well.

Disease is always a possibility.
Looks like scale. Search the questions on this site using the words “bay” and “scale” and you will see good answers.