Spots on marpleleafs

One of my acer has theese spots...is it bugs or fungus. I think they are already "eaten" on the underside, when the leaf opens. Please help....

Kind regards Yvonne

If the leaf looks "eaten" and is thinner in that spot it might be "Thrips," which do tend to attack foliage and flowers before they open. A standard defense is dormant oil when the tree has no leaves.

But, our maples are very susceptible to fungus. I am not sure that there is much you can do about fungus since it is airborne and thrives on wet conditions.

Billy

I found some Internet pages on Pear Thrips, which apparently are European in origin, but have spread to Maples in America. However, the damage shown on the websites is much worse than what you show.
I suppose that it is possible that in the natural range of the Thrip (Europe) it has natural enemies that keep it better controlled than in America.
If you were in the US I would say ask your county Agricultural Agent.

Billy

Hi Billy

Thanks for your answers, I think I can use them.....this marple is a new yamadori from this year, and I have sprayed the foliage a lot...maybe too much...if it is thrips, will provado do the trick next year. No one of my other maples is attaced, so I have high hopes .

Kind reggards Yvonne

Yvonne

I am not familiar with "Provado." As I mentioned a dormant oil spray would probably be the best solution. It smothers the overwintering bugs.
Once the buds open the damage is done and the Thrips are not a problem until next year.
The damage doesn't look like chemical burn that would come from a spray.
Horticultural chemicals are very different between your country and mine, but dormant oil is fairly benign and might be available to you.
Billy

I think Billy is talking about a Winter tar Oil washes which are restricted in the UK(not sure about rest of Europe). Armillatox in a very dilute form is recommended though. 50:1. Lime sulphur is tried and tested at 30:1

Hi Will, thanks

Isn't The Queen's English such fun. As I watch the beginnings of The Royal Wedding this early Friday morning, I am reminded that we share a common language but use words so differently.
Tar in America is a black gooey stuff that you can get on your feet when you swim where ships have cleared their bilges. I would never think of putting something that nasty on my plants.
When dry we even pave roads with it.