Yellow needles on JBP niwaki garden tree

Hello, This is about a large garden tree but many of the same principles apply.
Recently I have 2nd year needles turning yellow and dropping on a branch. At first I thought watering might be the culprit but after watching Ryan’s stream on scale and fungus I’m inclined to feel it is one of those instead. The effect is localized and the needles have sooty black spots. Would anyone venture an opinion on the cause and treatment?

Thank you
John Hovard