I was intrigued by the little yellow tufts on one berry on this bush. I did a search and came up with Cedar-hawthorn Rust (Crataegus).
Red Chokeberry (Aronia arbutifolia) – one with rust, Hudson River Park 6/17/2019 
Red Chokeberry (Aronia arbutifolia) – one with rust, Hudson River Park 6/17/2019
