<blockquote>To avoid the spread of fungal spores it is best to rake the affected leaves this fall. Destroy the leaves or remove them from your yard by bagging them for municipal collection. If you ignore tar spot and allow the fallen leaves to remain on the ground through the winter, your maples will develop tar spot again next year. If, however, you remove the infected leaves from the area you reduce the chances of the tree being infected the following year. After three years of diligently raking the fallen leaves around my maple tree, this was the first year it did not show signs of tar spot infection.</blockquote>
via <a href="http://www.greenlivingonline.com/article/fix-black-spots-maple-leaves">Fix Black Spots on Maple Leaves | Homes | Green Living</a>.