Rust fungus? It's only on one plant.

[cpurola]

Went out back to do my morning walk around and found my Wild, Wild, West CBD plant with this on the top.
I have many plants and none of the others have anything like it.
Outdoors in Southeast Mich.

Oh, and what can I do about it?

 

[cpurola]

I looked it up online and people said it's a fungus and recommend spraying copper, but I don't want to do that. So, I cut off all the infected bits and will monitor for new signs of it.

 

[LoveGrowingIt]

I found this about rust fungus at Dutch Passion.

Source: A visual guide to cannabis pests and diseases