Fungus/ Mould On Holly Tree

Question

Small area at moment, just on branches. No spots on leaves.

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Answer 1

It looks like a type of lichen, which is harmless. It doesn't need to be removed. Here is more:

https://www.gardeningknowhow.com/ornamental/fungus-lichen/treatment-tree-lichen.htm

https://www.gardeningknowhow.com/ornamental/fungus-lichen/usnea-lichen-information.htm