Is this a disease?

[Joel Williams]

Any advice for what's going on with the tree on the right here? I don't know how to treat the brown scale on it or if I need to do something about it. I live in MN.

 

[H-Ranch]

Any advice for what's going on with the tree on the right here? I don't know how to treat the brown scale on it or if I need to do something about it. I live in MN.

Looks like emerald ash borer damage to me. The tree is likely already a goner and there is nothing you can do.