Trees, Shrubs and Conifers: little red things all over maple tree leaves, 1 by jcoakley

jcoakley wrote:
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.