digital pictures of yellow/brownish and white spots

[Icarus]

John:

Here is a picture of a leaf from a tree with yellowish/brownish spots. Virtually every leaf has these spots.

Thanks.

Dan

 

[Treeman14]

Those are Tar Spots caused by the fungus, Rhytisma acerinum. Generally not a major problem, but can be controlled with fungicide. Selective pruning and disposing of fallen leaves also helps.

 

[Top it]

I am in aggrement with Treeman14 with the Rhytisma part but I think it is Rhytisma punctatum, sometimes called speckled tar spots.

 

[Kneejerk Bombas]

Top-it,
I think I know why you think it's Rytisima Punctatum, but why don't you tell us, so I don't look foolish guessing.
Also, did you look at the white spots what do you think, powdery mildew?

 

[Treeman14]

My bad. I didn't look at your location. It probably is punctatum.

 

[Top it]

Mike,

Why R.punctatum and not R.acerinum is that R. acerinum causes large tar spots (.05-2 cm across) and R. punctatum causes small ones, about 1mm in diamerer. Although early stages in development of acerinum closely resembles that of punctatum in which I doubt this is the case.