How do you prevent fungal infection when root pruning Deshojo&Co?

[ajm55555]

I still haven't found a definitive answer to how to prevent fungus from entering a delicate JM cultivar, like the Deshojo, when root pruning.
This is an air layer from South Korea/Japan. I had to do a major cut at the base to have a flatter root plain and this is the result. It pushed growth, then stopped and died.
I might have made errors but I would like to know all the precautions one would take when doing this.

• Should you disinfect the pruner every time you cut one root?
• Avoid days with high humidity in the air?
• Dip in a solution of hydrogen peroxide before filling in the soil?
• There must be something else...

Thank you!

 

[Wires_Guy_wires]

Was the bottom wound of the air layer properly healed?
If not, the tree has quite the surface area of possible entry areas for infections. Change the soil, plant stresses for a bit, fungi take advantage and boom, dead tree.

 

[ajm55555]

Was the bottom wound of the air layer properly healed?

Earlier this Spring, when I repotted it, I cut a section at the bottom (too many roots at different levels). Same thing for the bigger root on the left side.
How do you make it properly heal after a major root cut?

 

[leatherback]

How sure are you it was fungal and not just overworking the tree?

I must say, I never worry about fungal problems. I trim the roots and go on with my life. Fungal infections are rare I find. Maybe you are using a substrate that stays quite wet, facilitating them?

Fungi are all the time, everywhere. There is no preventing them from being around. So all you can do is provide optimal growing conditions.

 

[Forsoothe!]

I have a large Lionshead in my landscape and every time I trimmed it (I have learned my lesson now, I never touch it), I trim an inch, it dies back a foot. I've tried all the obvious cleanliness routines and more and nothing worked. I'm convinced that the pathogen is resident on the outside (bark) surface, and ain't going anywhere.

 

[Shibui]

Disinfecting after each root should not be necessary. If the tree has a problem in one root it will be right through the tree without your help.
I am not in the habit of disinfecting tools between trees (probably wish I was). Some JM get infected, most don't so I guess it is not about the tools or spreading some bug. Possibly susceptibility of individuals and maybe Deshojo is particularly susceptible, maybe not? Maybe this is a once off and will rarely happen again. I have not actually heard about Deshojo being more prone to death after repotting than other cultivare sor standard seedlings.
My experience suggests it is more about conditions after the root prune - too wet, too cold? Not sure.
Maybe the problem is something else entirely.
Maybe we are looking for a scapegoat for something that just happened?

If Deshojo is particularly susceptible to problems with bonsai techniques then we accept it is not suitable to bonsai.........

 

[ajm55555]

How sure are you it was fungal and not just overworking the tree?

What is this then?



I think the fresh cut soaked in moisture and the fungus. I could be wrong.

 

[ajm55555]

Maybe you are using a substrate that stays quite wet, facilitating them?

90% inorganic + 10% garden soil

 

[ajm55555]

If Deshojo is particularly susceptible to problems with bonsai techniques then we accept it is not suitable to bonsai.........

That's what Walter Pall thinks... Not sure if that was Verticillium or Pseudomonas, which are really two different levels of the problem.

https://walter-pall-bonsai.blogspot.com/search?q=deshojo

 

[leatherback]

What is this then?

Sitting in the rootzone. Higher up the trunk, there is nothing visible. Which to me would indicate not fungal. You would see the blak lines in the wood higher up afaik.

I have a little princess which has rootissues right now. I see the fungus moving up in the trunk with the bark turning black. Leaves sit still. I have little doubt mine will die. (Was not repotted, but I think the winter was too wet for it).

 

[ajm55555]

Sitting in the rootzone. Higher up the trunk, there is nothing visible. Which to me would indicate not fungal. You would see the blak lines in the wood higher up afaik.

I have a little princess which has rootissues right now. I see the fungus moving up in the trunk with the bark turning black. Leaves sit still. I have little doubt mine will die. (Was not repotted, but I think the winter was too wet for it).

The bark started turning black in some spots at the soil level and higher in the trunk in a seemingly unrelated part of the tree. Then kept progressing in spots, not really moving up consistently.
The roots didn't have many white tips, just a few and dying.

and not just overworking the tree?

I didn't realize that at the time but it could be. I'll keep this in mind. Thanks.

 

[Dav4]

Disinfecting after each root should not be necessary. If the tree has a problem in one root it will be right through the tree without your help.
I am not in the habit of disinfecting tools between trees (probably wish I was). Some JM get infected, most don't so I guess it is not about the tools or spreading some bug. Possibly susceptibility of individuals and maybe Deshojo is particularly susceptible, maybe not? Maybe this is a once off and will rarely happen again. I have not actually heard about Deshojo being more prone to death after repotting than other cultivare sor standard seedlings.
My experience suggests it is more about conditions after the root prune - too wet, too cold? Not sure.
Maybe the problem is something else entirely.
Maybe we are looking for a scapegoat for something that just happened?

If Deshojo is particularly susceptible to problems with bonsai techniques then we accept it is not suitable to bonsai.........

This is essentially my experience and thoughts as well.