The builder in my new construction neighborhood near Baltimore, MD planted about 70 trees this winter. These are mostly street trees adjacent to sidewalks and the road. They planted American Elms, flowering cherries, a few serviceberries in our common areas, and about 20 Red Sunset maple trees.

In the past week or two, I noticed that the leaves on the maples were getting some black spots. I'm a novice, did a bit of research, and assumed that it is tar spot. Now, almost every maple tree that the builder planted this winter has these spots, and many of the leaves are turning yellow. This seems a bit scarier than just the black spots.

Does anyone have thoughts on the problem, and ideas on what we should be doing to address the problem? Yellow leaves in May just seems terribly wrong. Could the trees have been infected last fall when they were probably all together before they were sold to my builder's landscaper?

Any thoughts would be greatly appreciated.