Seigen JM - dying leaves - help please

[SuperBonSaiyan]

Hi ausbonsai people,

I have a Seigan JM that I was planning on air-layering this spring, and unfortunately it's leaves are all dying. This happened in the past week. All my other JM's are doing fine, except this one. The leaves looked healthy and vibrant (bright orange/red colour) just a week ago, and now they all look like this:

sjm2.jpg

sjm1.jpg

Any suggestions on how to treat, or what might be wrong? It's in a free draining mix (same as all my other JM's), and watered the same as the others.

Cheers,
SBS

[KIRKY]

It looks like it dried out at some point. It’s easy to lose trees at the start of Spring as water requirements increase as the leaves start to burst. But the biggest killer imo is the wind you literally need to start watering really well daily once the warm weather and wind combo starts. Saying it’s in a loose mix same as others doesn’t mean much. It could be pot bound and the other trees are not etc… it’s clearly not happy regardless of the other trees. I’d start watering it more and you should see the leaves push out again. Make sure to liquid feed as it’s not having to push more growth.
Cheers
Kirky

[SuperBonSaiyan]

It looks like it dried out at some point. It’s easy to lose trees at the start of Spring as water requirements increase as the leaves start to burst. But the biggest killer imo is the wind you literally need to start watering really well daily once the warm weather and wind combo starts. Saying it’s in a loose mix same as others doesn’t mean much. It could be pot bound and the other trees are not etc… it’s clearly not happy regardless of the other trees. I’d start watering it more and you should see the leaves push out again. Make sure to liquid feed as it’s not having to push more growth.
Cheers
Kirky

I've been watering daily for a while now, especially once the leaves pushed out. Usually when the sphagnum layer on top would dry out - I'd water it. On windy days (when the sphagnum dried out often) I'd give it (and my other trees) a light misting 2-3 times a day.

Definitely not pot bound as it was repotted in July (minimal root pruning, mainly removing nursery soil).

I really hope you're right though (that I should see leaves push out again).

[shibui]

Take a close look at the base of the trunk. Black bark is a sign of fungal infection that kills the xylem and prevents water transport up to branches. That's why the symptoms look so much like dehydration.
Unfortunately when the black has completely surrounded the trunk it is too late to save the tree.
My experience has been that this infection is encouraged by soil being a bit wet through cooler winter and early spring. If noticed very early I have saved a couple of maples by keeping the pots on the dry side for the crucial weeks through early spring.

[SuperBonSaiyan]

Take a close look at the base of the trunk. Black bark is a sign of fungal infection that kills the xylem and prevents water transport up to branches. That's why the symptoms look so much like dehydration.
Unfortunately when the black has completely surrounded the trunk it is too late to save the tree.
My experience has been that this infection is encouraged by soil being a bit wet through cooler winter and early spring. If noticed very early I have saved a couple of maples by keeping the pots on the dry side for the crucial weeks through early spring.

Is this fungal infection something which can transmit to other trees? I was keeping a lookout on the leaves in case of aphids but didn't think to look at the trunk.

I probably watered too much...

[KIRKY]

The black to me looks more like it was potted deeper prior to repot. Time will tell.
Cheers
Kirky

[SuperBonSaiyan]

I hope Kirky is right. I worry Shibui is right. I'll keep it isolated and continue watering and we'll let the bonsai gods decide.

I'll spray with mancozeb tomorrow anyway.

[Akhi]

I had a forest and one of the trees jn the composition had the exact same symptoms last year.on two trees. Initially opened up and then suddenly paused and then dried out and died... no survival. The other trees in the composition continued on.

Had the same issue in a separate growpot also with that one is suspected a fungus and cut the trunk quickly and let it dry out and later in late summer a new growth came from the base. So I would say it is a fungus.

So dry out and once it's warmer back to normal feed Nd water.

[shibui]

Is this fungal infection something which can transmit to other trees? I was keeping a lookout on the leaves in case of aphids but didn't think to look at the trunk.

I think all fungal infections can move from tree to tree. That's how they survive in nature. This one seems to be relatively slow moving and relies on those wet, cool conditions to survive and infect a new host. I have not had it move aggressively, even when I kept infected trees to see what happens, so I would move the affected tree away from others but not worry overly much.

Can you post a good, clear close shot of the base of the trunk please, especially where the black meets the healthy bark. That will usually be definitive.

[SuperBonSaiyan]

My phone camera is pretty poor quality, so hopefully you can tell from these. If not, I'll try to take a few more pictures in the daylight tomorrow.

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[shibui]

Not as conclusive as I thought. The higher dark bark looks like normal aging bark There's some blacker spots right down low that are not so good but could just be wet bark

[SuperBonSaiyan]

The blackness has spread up onto the branches

I scratched a bit of the bark and it's green underneath, but it's not looking good. No new leaf buds have popped open for a few weeks now.