Multiple junk mail folders in outlook 2013

4 additional junk mail folders (junk mail1, junk mail 2, ...) have appeared in my IMAP email account in Outlook 2013. Why has this happened? I tried to delete them but this hasn't worked.

I use this mailbox in my iphone; i found this:

https://discussions.apple.com/thread/5730933?tstart=0

but i using IOS 9 and doesn't  work.

Thank you.