What pest or fungus is that?

[GreenDwarf]

Hi,
I have two bonsai trees (fukien tree and bluebell) that are having a few new leaves that turn yellow and become weak enough to fall when I touch them. Every day I see new ones. At first I thought it was some fungal issue so I used daconil (chlorothalonil) but it didn't seem to stop the disease. Any idea of what that could be and how to treat it. I already isolated the 2 trees as it is the rainy season over here and humidity is through the roof. Apart from that both trees look healthy. Is it trivial or concerning?
Thank you.

 

[Tieball]

I don’t know the answer for your tree. I had a Fukien tree....once....seemed every time I moved it, rotated it or otherwise changed something....leaves would begin to fall. Leaves also fell off if overwatered....or underwatered. It was, as you described, that I could touch leaves and they’d fall. At one point it dropped all its leaves and gave up growing....and I gave up trying. I moved on. So, no answer, but keep an eye out for bud formation at those leaf drop points. The black spotting seems like a fungus attack....which could be due to the moisture of the rainy season.

Not on a Fukien tree...but on Elm. Perhaps related. I found black spotted leaves. At one point I leaf pruned every leaf off then sprayed. The tree came back okay. At that time I also moved the tree to a more sun lighted area with more air circulation. I really thought the fungus was started because where it was located had very little air circulation and a dampness developed around the tree.

Some Elm trees in the ground developed black spotting. Can’t move those though. But I did clear out weeds in the area so dampness could be minimized, air better circulated, and then removed a branch from a giant oak tree that was shading and blocking wind movement. I surrounded the trees in the ground with a layer of Turface. Actually seemed to work okay. I don’t know which change contributed the most...but I was good with the result.

Ho Chi Minh, and outlying cities, have a lot of mildew growing....everywhere....especially where there is shade and minimal air circulation.

 

[GreenDwarf]

Thank you so m

I don’t know the answer for your tree. I had a Fukien tree....once....seemed every time I moved it, rotated it or otherwise changed something....leaves would begin to fall. Leaves also fell off if overwatered....or underwatered. It was, as you described, that I could touch leaves and they’d fall. At one point it dropped all its leaves and gave up growing....and I gave up trying. I moved on. So, no answer, but keep an eye out for bud formation at those leaf drop points. The black spotting seems like a fungus attack....which could be due to the moisture of the rainy season.

Not on a Fukien tree...but on Elm. Perhaps related. I found black spotted leaves. At one point I leaf pruned every leaf off then sprayed. The tree came back okay. At that time I also moved the tree to a more sun lighted area with more air circulation. I really thought the fungus was started because where it was located had very little air circulation and a dampness developed around the tree.

Some Elm trees in the ground developed black spotting. Can’t move those though. But I did clear out weeds in the area so dampness could be minimized, air better circulated, and then removed a branch from a giant oak tree that was shading and blocking wind movement. I surrounded the trees in the ground with a layer of Turface. Actually seemed to work okay. I don’t know which change contributed the most...but I was good with the result.

Ho Chi Minh, and outlying cities, have a lot of mildew growing....everywhere....especially where there is shade and minimal air circulation.

Thank you so much for your reply. I wil try adding air circulation on my balcony with fans and also avoid watering the whole tree to see if that helps. Unfortunately we have been lacking sun lately. Can't wait for the sun to come back. Hopefully it will sort things out.

 

[Tieball]

Are you on the back end of the rainy season now? Done with it soon?
I imagine that a balcony, with somewhat of an enclosure, could be just still...no air movement. Ha!.....then the dry season arrives and you get hot every day and probably still only a minimum of air movement or still no air movement. Challenging on the balcony. Maybe one of those small solar powered fans would be good.....if no one can see it.

 

[Tieball]

I would have thought you take on a Ficus tree or a Mai tree....more stable in the Vietnam weather I think. Those trees are offered fairly low cost around the holiday at the flower shows...lots of bargaining room near the end of the show display time. Sellers don’t want to take trees home with them. Sale time in the park. Perhaps with minimum sun even a Ficus would suffer setbacks. Vietnam has some tough trees though.

Well...at least you don’t have snow down where you are located. Ha! I was imagining if all that rain was really snow. Yikes!

 

[GreenDwarf]

I would have thought you take on a Ficus tree or a Mai tree....more stable in the Vietnam weather I think. Those trees are offered fairly low cost around the holiday at the flower shows...lots of bargaining room near the end of the show display time. Sellers don’t want to take trees home with them. Sale time in the park. Perhaps with minimum sun even a Ficus would suffer setbacks. Vietnam has some tough trees though.

Well...at least you don’t have snow down where you are located. Ha! I was imagining if all that rain was really snow. Yikes!

Haha I can see you've been around and know your stuff. Yeah since my balcony barely gets any sun, I installed some led grow lights full specrum. They are the 80w bulb kinds. So far so good but I might update to 100w if I get a chance. They are fairly cheap and don't burn the leaves.

 

[GreenDwarf]

Moreover, I hope I didnt go too hard on the osmocote lol!

 

[Tieball]

Excellent...you’ve got quite a set-up going on. Admittedly....I had a much smaller balcony pictured. Your balcony should get air and light....unless you’re just facing the opposite of light and wind. I think that if you add a few more lights your wiring will begin looking more like the utility poles around the town corners.....Maybe the collection of wiring is not that bad around you though.

Your trees look healthy. Nice work!

 

[Cypress187]

shade and minimal air circulation.

I also might have this problem, my plants aren't doing so great.

 

[GreenDwarf]

I also might have this problem, my plants aren't doing so great.

Try led and fan my friend

 

[GreenDwarf]

Excellent...you’ve got quite a set-up going on. Admittedly....I had a much smaller balcony pictured. Your balcony should get air and light....unless you’re just facing the opposite of light and wind. I think that if you add a few more lights your wiring will begin looking more like the utility poles around the town corners.....Maybe the collection of wiring is not that bad around you though.

Your trees look healthy. Nice work!

Haha you definitely know what's up!
I'm lucky because Phu My Hung on the outskirts of Saigon, the neighborhood where I live, have stepped up their wiring game lol therefore I am safe to walk through flooded streets...

 

[GreenDwarf]

Back to the topic. I defoliated all the trees that didn't have nice leaves
One of the perks of living in SEA is that you can do that anytime ?