On Apr 8, 2007, jugglerguy from Alpena, MI (Zone 4b) wrote:
The maple eyespot gall midge does not harm the tree, other than making the leaves look really unusual. This is the first year I noticed it on a wild acer rubrum in my back yard. I only found a few leaves like this.
The spots are caused by a maggot that excretes something onto the leaves as they eat them. They then fall off and live the rest of the year in the soil beneath the tree. Their numbers may fluctuate from year to year depending on weather conditions.