Show spam mail folder and sync settings for LG G4?

[AC Question]

On my previous phone (HTC One) I could choose not to sync spam folders to my phone, but on my LG G4 it syncs all spam directly to my inbox. When I go into mail settings and select "show all folders" there is no spam folder or any of my other Yahoo folders, so all mail, including spam comes straight to my inbox. How do I set the default email app to properly show ALL folders and set syncing so I don't get spam?

I'm hoping I've just overlooked something simple and my upgrade hasn't meant a reduction in simple functions!