I've just been to your profile page and there is a question on your rowan that you've asked and with a photograph too. Have looked at it, but it's hard to tell whether the white spots are objects sitting on the leaf, indentations in the leaf, or something else. any chance you could take a close up of some of the spots so I can see them more clearly? At the moment I'm thinking they're some sort of gall, because they look as if they're standing proud of the leaf, but its hard to tell. And obviously, whilst you don't think your photo is loading and attaching to the question, it is...

Hi Noticed very similar spots on our rowan last year for the first time. Much worse this year. Did you ever get to the bottom of it as I can't find info anywhere else on the web?

Without a clear, close up photo of the spots, its impossible to tell what it might be.