These galls on Ulmus sp. tree leaves are caused by an insect but I do not know the name. Can you help me please and is it infestation to other trees around?
I also believe that it's a Tetraneura ulmi whose gallels, along with those of Eriosoma lanuginosum, are currently being studied as the liquid contained in them could be "the forgotten ingredient" of classical paints. The research is aimed at having an interesting new substance that can be used in the preparation of violin paints.
