The silver maple capitate mite ( Vasates quadripedes ) is a herbivorous mite from the family Eriophyidae . Monophage, haloformer, damages North American maples: silver maple ( Acer saccharinum ), sugar maple ( Acer saccharum ), red maple ( Acer rubrum ). Induces the formation of small capitate galls on the leaves. Comes from North America. In the 20th century, with planting material, it was brought to Europe. Recorded in 1957 in Latvia, currently widespread in Europe on silver maple ( Acer saccharinum ).
Hi, arborist here. I would advise against using pesticides to control this issue. The galls are completely harmless to the tree and the pesticides may cause harm both to you if you were accidentally exposed, and definitely to other invertebrates, many of which may be beneficial. Some may even help control the mites in future years.
Great, that’s basically what I’d recommend. Disposing of any leaves you pull off the tree and those on the ground away from the tree should help reduce the intensity of the issue.