Chinese elm newbie - spots on leaves

[AndreyC]

Hi all, new to bonsais here, I got this chinese elm a couple of weeks ago and I saw some weird black spots on the underside of the leaves. Im thinking it could be a fungal infection. I have removed the leaves that were more affected and sprayed some copper fungicide and a little bit of insecticide as well.
A week later I see that there ar still some dark grey spots but nothing as major... Should I be worried? It looks happy, a lot of new shoots and leaves are growing and those dont seem to be affected yet.
If you have any advice for me, it's greatly appreciated
[image][https://ibb.co/McxFhsM/image]
[image]https://ibb.co/MhQ349s[/image]

[AndreyC]

Reposting the first picture, i messed up.
https://ibb.co/McxFhsM
Also more data: I live in Spain and its very hot at the moment, about 38 degrees Celsius. I've been watering it daily by submersion so maybe that has something to do with it... The spots already came on the plant since I received it though.

[Akhi]

Yes it's fungus and i generally get that on my roses, looks very healthy so I won't be too stressed, spray a sulphur based fungicide and when it sheds all leaves in winter do a thorough clean of the leaves and spray once again to reduce the number of spores. Do that a few seasons and you should have none.

[AndreyC]

Yes it's fungus and i generally get that on my roses, looks very healthy so I won't be too stressed, spray a sulphur based fungicide and when it sheds all leaves in winter do a thorough clean of the leaves and spray once again to reduce the number of spores. Do that a few seasons and you should have none.

Thanks so much for the reply, so the copper fungicide isn't doing much then, I will buy a Sulphur based one and try. I also wanted to do some wiring as well, when do you recommend it? Once it sheds the leaves?

[Macros]

Yes, with deciduous trees, it’s always easier to wire with the leaves off, but in reality, you can wire during the growing season. You obviously just need to take more care not to damage the leaves, but also because there can be more water movement through the branches
I hope the treatment goes well and you get on top of it

[shibui]

Depending on local climate Chinese elm may not shed leaves in winter. In warmer areas and through warmer winters they are only semi-deciduous so many growers must wire, prune and repot Chinese elm while they still have leaves.
Also depends on variety. Catlin elm retains leaves much more than corky bark or the reticulated bark variety.
Wire and bend Chinese elm whenever you need to and have the opportunity. Personally, I develop Chinese elm much more by pruning than wiring.

Be very wary of trying to wire and bend Hokkaido variety of Chinese elm. Those are EXTREMELY brittle so most branches and even smaller twigs will break before bending.

[AndreyC]

Thank you all for the advice, I got some sulphur base fungicide and im applying it, hopefully it will get better. As for the wiring I will try and move a small branch very carefully and see how it goes. As I said im very new to this so I got a Chinese elm after reading that they are fairly strong when it come to rookie mistakes. I hope to take good care of it