A series of red galls on an alder leaf and several tiny green mites. I do not know if the mites have emerged fromm the galls.
No interactions present.
I think this is Phytopus laevis (= Eriophyes laevis), but I don't think it is accompanied by mites, they look like young aphids to me (or possibly young leafhoppers?).
Entomologist and biological recorder
Lat/Lng: 52.7, -2.6
OS grid ref: SJ6412