Bacterial? Rapid infection on japanese maple

[Lars Grimm]

Not unless it got below 75F at night. I don't know the conditions at 'North Carolina', but I don't think it gets this cool at night this time of the year in Charlotte.

So, a new verticillium infection, say from the pruners, would not be active. An existing infection would not be advancing.


Dip/drench the roots in 2 tablespoons 3% hydrogen peroxide in a quart of water. It will take care of bacteria as well.

Durham, North Carolina. Here is the weather starting on day 2

 

[Lars Grimm]

I ask this question whenever a tree goes south this quickly in warmer months--Do you own a cat? If so, does the cat like to hang around your trees? If so, consider cat pee being a problem. In a pot that small, a does of urine with the dissolved salts and relative acidity could be a big problem.

I do own a cat. He hasn't shown too much interest in my plants before, but he roams around in the backyard at night so who knows what he does.

 

[kouyou]

I ask this question whenever a tree goes south this quickly in warmer months--Do you own a cat? If so, does the cat like to hang around your trees? If so, consider cat pee being a problem. In a pot that small, a does of urine with the dissolved salts and relative acidity could be a big problem.

That's really interesting! I don't have any cats, but my neighbors do, and they clearly prefer the trees i have in wide grow-out boxes. The cats never seem to dig or play with the substrate, so I always let them be.

But the danger you've signaled never crossed my mind before -- Thank you @rockm !!

Time to put the mouse traps out! A pinched foot or tail will keep them away for good!

 

[GGB]

be careful with that tree. I don't blame you for wanting to try to bring it back, but if it's infected you're just keeping the spores around your yard longer. Coming from a guy who has infected pine needles all over his yard. It's a shame when you doom a genus for yourself

 

[Lars Grimm]

Here are a few more pictures from today. I went ahead and cut one of the branches off that was probably accessory and then made a longitudinal cut. I don't think the vasculature is involved, but you all be the judge.

Picture 1: Primary branch with blackened base.


Picture 2: Longitudinal cut.


Picture 3: Showing cross section


Picture 4: Peeled back the bark to show the black is just superficial.


Showing the whole tree dry now.

 

[coh]

You know...I'm pretty sure I've seen branches turn black after pruning, for example if you prune and leave a stump with no node- the branch will die back to the next node and may turn black as it does so. That suggests your problem might actually have been something that severely damaged or killed the roots (or many roots). This would then lead to leaves dropping and perhaps whole branches dying back and turning black. The question then would be, what happened to the roots? Hard to imagine a single missed watering would kill the whole tree but then again, I don't deal with the kind of heat you get down there. Sure looks like everything on that left/top side is gone but maybe the branches on the right have a chance?

I'd probably pull it out of the pot and see what is going on down below (maybe wait a little bit and see if there are signs of any new buds).

 

[rockm]

I don't think that's V wilt. That typically doesn't kill a tree all at once. It also leaves behind profound black staining on the inside of branches.

V. wilt typically shuts down circulation of sap in some branches but not others, which leads to one section or branch dieing off. Then another over months, or even years...It typically doesn't kill an entire tree in five days...

 

[kouyou]

very sorry to see this happening @Lars Grimm

in the last photo that you just posted, the roots look too dark to me. do you have any picture(s) of the tree *before* you noticed any symptoms? maybe from this spring? or last fall? it would be nice to approximate how long the roots have been black like this for, just for the sake of discussion and clarity

when you first posted, like others my initial feeling was that the roots had completely, or almost completely failed (maybe from a day without water?) since the problem affected all of the leaves all at once, rather than in different areas. (it reacted in the same way that a branch does when you sever it from a tree, for example). but the black spots were throwing me off. now it seems like your roots have that same blackness.

edit: was it repotted this spring? (i.e. were the roots already compromised?)

i'm looking forward to seeing what conclusions our usual experts will arrive at with this new information!

and @Leo in N E Illinois hasn't chimed in yet!

 

[penumbra]

I still think its root rot. You haven't shown any pictures to discount this and you still haven't shown close ups of the roots.

 

[Lars Grimm]

I still think its root rot. You haven't shown any pictures to discount this and you still haven't shown close ups of the roots.

I think the roots/base have always looked like this. Here is a thread from a while back showing the initial progression. You can see that it has always looked darker through a combination of exfoliating bark, moss, etc.

 

[River's Edge]

Here are a few more pictures from today. I went ahead and cut one of the branches off that was probably accessory and then made a longitudinal cut. I don't think the vasculature is involved, but you all be the judge.

Picture 1: Primary branch with blackened base.
View attachment 258485

Picture 2: Longitudinal cut.
View attachment 258486

Picture 3: Showing cross section
View attachment 258487

Picture 4: Peeled back the bark to show the black is just superficial.
View attachment 258488

Showing the whole tree dry now.
View attachment 258489

Will be very curious to see how this turns out, keep us posted please!

 

[penumbra]

I think the roots/base have always looked like this. Here is a thread from a while back showing the initial progression. You can see that it has always looked darker through a combination of exfoliating bark, moss, etc.

The color of the base is not at all what my concern is. What about the roots? Either take it out of the pot and look or don't. I'm done here. Best of luck.

 

[Lars Grimm]

The color of the base is not at all what my concern is. What about the roots? Either take it out of the pot and look or don't. I'm done here. Best of luck.

Gotcha. I appreciate the insights. I am going to slip it out tomorrow and take a look at the roots. I'll post pictures then. Based on the collective feedback, I am coming around to the idea that something (heat, fungus, cat pee) hit the roots really hard.

 

[Cable]

I think Sorce is on the right track on this one.

 

[Shima]

BUT, ...
Verticillium doesn't grow at temperatures above 75F.



Another possibility is that a day of not watering and in the sun, the root temperatures would skyrocket and could have been well above the ambient air temperature. Roots definitely are dying when their at temperatures above 115F/45C. Possibly the roots got toasted on day 2.

Dark open soil and no moss to protect, Doesn't take long to bake roots.

 

[Lars Grimm]

Dark open soil and no moss to protect, Doesn't take long to bake roots.

There was moss on it when it happened, but I took it off for the photos. Definitely dark soil though (pure akadama).

 

[Lars Grimm]

I went ahead and slipped it out of the pot. I've never seen root rot in real life, but the roots didn't smell and they didn't look sodden. They looked a bit dessicated. I took a bunch of photos.









I went ahead and repotted it into a new container after removing a bunch of the old soil. I left all the roots in place and covered the surface with sphagnum. I'm not really sure how to proceed from here. I guess just leave it and hope for the best?

 

[coh]

If you scratch the bark on the big surface roots, is there green cambium underneath? Those roots do look a little dark but it's hard to tell if that's from moisture/old moss/algae or the roots themselves are dark.

 

[Lars Grimm]

If you scratch the bark on the big surface roots, is there green cambium underneath? Those roots do look a little dark but it's hard to tell if that's from moisture/old moss/algae or the roots themselves are dark.

 

[kouyou]

any updates @Lars Grimm ?

at first glance those roots look very dry and brittle to me (even where your akadama looks damp). the color of these roots i was just looking at might be a good point of comparison:

Japanese Maple in SA

After trolling this forum for several months i decided to start my very own progression thread on my JM. It has been a challenge keeping the foliage in good condition until winter however i believe im getting the hang of it. I live in Cape Town, South Africa so for those that have visited...

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