Maple with black spots and brown powder

Asked August 17, 2017, 8:23 PM EDT

My 6 year old silver maple has black spots on the leaves on the green side and on the silver side has a brown powdery substance. On the green side there are yellow marks that correspond with the location of the brown powder on the other side. Any help on how to treat would be appreciated.

Hennepin County Minnesota maple trees horticulture

3 Responses

This looks like tar spot, a common fungal infection on maples, which does not threaten the health of the tree and rarely requires treatment:
http://hort.uwex.edu/articles/tar-spot/
http://msue.anr.msu.edu/news/why_do_my_maple_leaves_have_spots

Does it typically have the brown powdery substance on the opposites side of the leaf?

I'm not sure of the answer to your question. The infection looks like tar spot, but could be one of a number of other spot diseases, all harmless to an otherwise healthy tree. Check this site, which has a photo of the underside of a maple leaf with tar spot:
http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advi...

And this site discusses various spot diseases, fungal and bacterial:
http://www.extension.umn.edu/garden/yard-garden/trees-shrubs/management-of-leaf-spot-diseases/

Finally, if you think your tree has something more serious than one of these spot diseases, here is a link for finding a certified arborist:
http://www.isa-arbor.com/findanarborist/arboristsearch.aspx