Thank you for contacting Ask Extension.

I believe your problem is caused by anthracnose, which is a fungal disease that causes light brown or tan areas on the leaves, often starting at the edges and spreading inward. This disease is more prevalent in rainy seasons and can be managed with fungicides sprayed on as leaves open in the spring

Anthracnose fungi overwinter in infected leaves on the ground. Canker-causing anthracnose fungi, such as the sycamore anthracnose fungus, also overwinter in twigs on the ground or in cankered twigs that remain on the tree. Microscopic spores of most anthracnose fungi are produced in infected tissues during April and May. The spores are blown and splashed to the buds and young leaves and, with favorable moisture conditions, penetrate and infect the swelling buds and unfolding leaves. Prolonged rainfall helps the fungus to spread rapidly.

Anthracnose diseases do not typically pose a serious threat to the health of a tree, so fungicide treatment is not usually recommended. However, there are general cultural management tactics to minimize anthracnose infections and severity on trees in the landscape. Tactics include raking and removing leaves and dead twigs to reduce fungal inoculum for future infections. Throw the leaves away, instead of composting, to ensure that you are not reinfecting the trees again. Prune out and remove dead twigs and branches. Pruning to thin the crown of the tree will promote foliar drying, which will minimize infections. When planting trees, space adequately and avoid crowding to promote foliar drying. Promoting overall good health of trees in the landscape will also allow a tree to better withstand damage from anthracnose.

I have included several publications on how and what to spray, if you choose to, and how to mechanically clean up around the tree. If you maintain a healthy environment around the tree, and what is falling off of the tree, then next year should be better. If we can be of further help, please contact us back.

Maple anthracnose - MSU Extension

https://edis.ifas.ufl.edu/publication/ST052

https://hort.extension.wisc.edu/articles/anthracnose/#:~:text=Anthracnose%20is%20the%20name%20of%20several%20common%20fungal,and%20walnut.%20Anthracnose%20typically%20affects%20young%20leaf%20tissue.

Good morning, 

These leaves do not have light brown or tan spots.  They are pretty dark in color.  The articles you attached show pictures of the leaves and my leaves don't seem to be quite the same.  I could be wrong.  But I have attached a few more pictures.  Also, if what my tree has is what you are saying it has, what is the best product to use for it?

Thank you in advance, 

Jen H

Hello,

Anthracnose begins as brown spots and becomes darker as the disease progresses. The leaves in the pictures are sugar maples, whereas yours is a red maple. But Anthracnose affects all maples, and probably one of the biggest problems with maple trees. 

I copied this from the MSU publication: In general, fungicides are not recommended for control of shade tree anthracnose. Large well established trees that are otherwise healthy can withstand the damage without serious long term affects. In time, severely infected plants will push forth a new flush of growth from buds that would otherwise have remained dormant. There are some situations where chemical control is warranted. Some examples are protection of nursery stock, smaller trees or trees that are not well established, or in “show case” areas where for aesthetic reasons it is important to maintain a disease-free tree. Applications of copper-based fungicides, chlorothalonil, thiophanate-methyl, mancozeb, or Spectro will help protect foliage from infection. Refer to the fungicide label for application rates and intervals.

You really do not need to treat, but if you want, find a product that has one of the bold (above) ingredients in it, and follow the instructions on the label. We cannot endorse one product over another, which is why we give you the active ingredient to look for.

Hope this helps,