Dieback prevention

[junmilo]

Hi,

Quick question... When do you all spray copper on JM if there is a dieback issue? Can I spray in middle of winter? Or before new growth comes out in early spring.

Thank you

JZ

 

[Wires_Guy_wires]

Depends on the issue. If the dieback is caused by frost, copper isn't going to help.
If it's bacterial, peroxide would work better. Every two weeks. But a systemic antibiotic would work better.
If it's fungal, then copper sulphate works. But I haven't had those issues so I don't know how often you should spray them. In pines I do it monthly in spring.

 

[cbroad]

Dormant sprays for bacteria/fungus and pests in the winter are very common on landscape and production trees.

For people with fungal issues because of high humidity during the growing season, late winter and early spring sprays can be their only saving grace.

I think a typical schedule is to spray during mid winter and then again as the buds are swelling.

 

[Deleted member 21616]

Quick question... When do you all spray copper on JM if there is a dieback issue? Can I spray in middle of winter? Or before new growth comes out in early spring.

Hi @junmilo - nice to see a fellow Canadian here!

why do you have dieback? did you perform a chop or remove a major branch? And why do you think that dieback would be related to spraying? Maybe I am missing something here.

In general, i spray lime sulphur:

1:12 ratio after leaf drop

1:12 ratio in later winter/early spring, just as buds start to swell. In the future, I will do 1:1 instead of 1:12 in late winter/early spring, to kill fungus and whiten trunk at the same time

Here are links to a few threads that I keep in my notes under four separate headings: "dormant spray" "fungus" and "insects" and "trunk whitening"

https://nebaribonsai.wordpress.com/2013/03/30/more-from-the-chishio-workshop/

https://www.bonsainut.com/threads/is-it-me-or-the-sulphur.27009/#post-578743

https://www.bonsainut.com/threads/preventative-dormant-spraying.31787/#post-525842

https://www.bonsainut.com/threads/has-the-good-lime-sulfur-been-banned-in-california.24171/

https://www.facebook.com/notes/houston-bonsai-society/dormant-spraying/1335155469848406/

https://www.facebook.com/notes/hous...ose-on-the-texas-gulf-coast/1384161804947772/

 

[ysrgrathe]

People seem to use a wide variety of concentrations. I've used 1:32 or even 1:64 when in leaf. 1:12 is quite strong, 1:1 is something else. I've seen lime sulfur used to great effect to whiten trunks though so I have no doubt it is effective. Would love to hear more about others practices here.

 

[Paulpash]

For growing bonsai the biggest 'dieback' threat is from chops and the Acer's tendency to compartmentalize back to a sap drawer.

 

[junmilo]

Hi @junmilo - nice to see a fellow Canadian here!

why do you have dieback? did you perform a chop or remove a major branch? And why do you think that dieback would be related to spraying? Maybe I am missing something here.

In general, i spray lime sulphur:

1:12 ratio after leaf drop

1:12 ratio in later winter/early spring, just as buds start to swell. In the future, I will do 1:1 instead of 1:12 in late winter/early spring, to kill fungus and whiten trunk at the same time

Here are links to a few threads that I keep in my notes under four separate headings: "dormant spray" "fungus" and "insects" and "trunk whitening"

https://nebaribonsai.wordpress.com/2013/03/30/more-from-the-chishio-workshop/

https://www.bonsainut.com/threads/is-it-me-or-the-sulphur.27009/#post-578743

https://www.bonsainut.com/threads/preventative-dormant-spraying.31787/#post-525842

https://www.bonsainut.com/threads/has-the-good-lime-sulfur-been-banned-in-california.24171/

https://www.facebook.com/notes/houston-bonsai-society/dormant-spraying/1335155469848406/

https://www.facebook.com/notes/hous...ose-on-the-texas-gulf-coast/1384161804947772/

Hi

Was from a chop.. And every spring... There is a little die back...i see black...

J

 

[0soyoung]

To be clear, winter die back isn't necessarily caused by a pathogen. Acer palmatum, for one, has very low phloem pressure when not in leaf - at least that is how I interpret the phenomenon.

Carbohydrates and auxin flow down the tree in the phloem (aka, inner bark). A pressure is developed at the leaves by living cells that actively load these materials with water into the phloem tubes, This little bit of pressure means that this stuff may actually be transported up, against the force of gravity. So, if you pruned in an internode during the growing season, the cambium and bark can stay alive. Importantly, auxin can be moved up and get loaded into the Polar Auxin Transport stream in cambium cells that importantly signals 'life above'. During winter this pressure drops and die back inevitably proceeds to the node below where buds maintain the PAT. When this happens, the cambium dies, causes the bark to darken and signals living cells in the wood (the the effect) that there is no life above, seal off the xylem here.

All very hand wavy, maybe, but it does explain why die back is seen to be a consequence of winter. However, one can observe this same problem when layering some varieties of acer palmatum - Higasayama, for one (which I attribute to having very low phloem pressures even during the growing season).

If one chops late in the season, there is little or no time to grow new phloem tissues and one gets this kind of die back - the pattern of phloem flow is quite clear.



On the other hand, it is less likely to happen when chops or major cuts are made in spring, giving time to grow new phloem that distributes stuff more evenly around the bole. I made this chop in March 2015 and instead there is no significant die back in evidence a year later

Moreover, as @Paulpash noted, sap producers (branches) distributed around the bole help to limit the die back (over just buds on a node.


In case I've gone too far afield, my point is: with acer palmatum, die back to a node (and maybe further) is inevitable in winter. NO PATHOGEN IS INVOLVED - simply, be aware.