Yeah before assuming the worst, do what you can to help your plant. To me, the soil it's planted in doesn't look the best. Since mulching is a good idea for so many reasons, maybe mulch with a layer good compost thick enough to hide the soil underneath, then pile with additional mulching material of your choice.
Whether fungal or bacterial, remove entire or affected portion of the leaves using clean tools. I like to spray with milk solution and willow tea (branch-tip leaves and stripped bark) first, then think about other sprays. If I have AACT brewing, I would spray with that.
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