On my way out with the kids this morning I noticed these on the maple tree that is growing near our back alley. What the heck are they and could they get on other plants/trees? I also noticed many of the tree's leaves are riddled with holes. Incidentally, this tree is growing into the fence between our yard and the neighbor's and I can almost guarantee it wasn't planted there on purpose. I wouldn't mind getting rid of it but I know we're not prepared for the expense right now.
Galls caused by Eriophyes mites. They don't cause any significant damage; also each mite species is unique to each tree species, so they won't spread to other tree species.
Resin
Good to know, Resin, thank you!
