I have just started gardening. My first tree purchase was a Yoshino Cherry (Prunus y yedoensis Ivensii). After potting it into a larger pot, it has started to have lots of holes appear in the leaves. I have found 1 leaf with a collection of bugs on it but no idea what they are or how to treat it.
I am in East Lothian, Scotland if that helps.
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Update Image from tips of branches, believed to be new growth but could be a symptom.
It's cherry blackfly infestation - needs spraying before the leaf curl gets any worse. Westland Plant Rescue Fruit and Veg bugkiller should do it - you should also use Vitax Winter Tree wash during winter - this pest overwinters on the plant. As the leaves have started curling, its a little late for the Westland spray to be truly effective, but I'd use it anyway, and make sure you treat the tree during winter with the Vitax solution.
If you google cherry blackfly, the RHS advice page on this should come up which will give you alternative proprietary treatments.
