Powdery substance on magnolia tree

[Tmann]

I have a powdery substance that is growing on my magnolia tree, it is also on the leaves of my peonies. It started on the peonies shortly after they were finished blooming and I noticed it on the magnolia about a month ago. My weather has been hot and dry but I water regularly. I can't spray them with anything b/c they are very close to my pond and stream.

Any ideas what may be causing it?

 

[CanadianLori]

Is the powdery stuff just on the leaves?

 

[JSD]

This could be powdery mildew. But the following site suggests that a Magnolia with powdery mildew might also have other problems causing stress that are worth investigation: http://gardening.yardener.com/questions/How-To-Protect-Magnolia-Tree-From-Powdery-Mildew.

 

[treepro]

Very Nice . if you find any ideas about this , pls inform me . thanks .
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