Carpinus Betulus Fungus Destroicus

Good morning all the BBB (Big Bonsai Brains),
could anyone of you be so helpful and try to identify that terrible thing which is trying to kill my little hornbeam? As far as I am concerned it seems like some kind of a fungal disease. We’ve experienced an unusually wet May which probably help with the spread of that…thing. It seems like a white cotton-like substance on the leaves which eventualy causes a brown spots on the leaves (does not seem like aphids). Could any of you BBB please help with the identification and possibly suggest a treatment? This is a single plant… However, I have a big hornbeam forrest living nearby which I really do not want to lose. I’m glad for any suggestions.
Thank you very much and may the Mr. Kato guide your steps. Cheers.

Hi @Jan
Could be mildew? Look for a spry for roses, get it in the sun and try not to get the leaves too wet.

I agree, it kind of looks like powdery mildew. There are various fungicides that you can use to treat it.

Hi guys,
thank you very much for the help. It truly seems like a powdery mildew. It’s just a pitty that even european European Hornbeam cultivated in the middle of Europe in a country in European union by an European from a european nursery in a european pot made by european potter still gets diseased, even though other non-european trees from non european countries in non-european pots cultivated by a poor little european, don’t.
Thanks for the help guys!

1 Like

Everywhere is changing and we are all facing new challenges. Try to look at these as the plant telling you it’s not happy, and see what you can do to cheer it up. Sprays may get rid of the mildew, but it would not have struck if there wasn’t a weakness.


Well, the tree went through a significant root reduction this spring. Also, we went from winter temperatures straight to 25C (80F) and then we’ve hit a May when it was just raining and cold. I probably know where it is coming from.
Anyway, huge thanks to everyone.

Refreshing perspective and sage advice @AndyK.

All the best @Jan!


1 Like

Yeah, that will do it!

@Jan .How did this play out? Hope it survived.
Did you use winter sulfer spray?