AusBonsai

Hi,

Appreciate if someone can shed some light.
I have a 1.5m Japanse "Deshojo" red maple ( not trained as bonsai ) in a large deep pot for 5 years (have not repotted since).
And in the last year, it has developed peeling/die back on the bark on one side of all branches only, I can not find any bugs on them. The tree still produce leaves and no branch die back yet.
The dead bark spoil the look. I am concern this will kill the tree down the track. Any advice and helps are much appreciated.

Khanh

Hi Kahnh ,i have experienced this for numerous years , 1 tree has a borer grub however the holes can be seen with sawdust around them .These usually bleed sap .On all the other maples including a large Bonsai the bark has died and the only thing i can put it down to is sunburn .It has never appeared on the sheltered side on the trees or inside the canopy where the foliage covers the limbs , it has appeared inside where the foliage in non existant .The sun burns the bark and during winter water penetrates the grey bark splitting it and it becomes quite evident ,it takes years to heal these wounds .Hope this helps .Cheers Alpineart

Caterpillars and other pests eat the bark, so it disappears. But if it is loose and you can peel it off, the tree most ptobably has a fungus disease called cambium necrosis, which means that the green layer under the top bark dies off. It can affect lots of tree species; it's for ex. a menace in the fruit tree industry and I've had it on an English elm. It is caused by pruning without sealing or by damage to the bark caused by pests or some accident, which leaves the lower bark layers exposed to fungus spores. You treat it by cutting away all the loose bark until you get to clean green cambium which sticks to the wood, after which you paint the whole exposed part with a fungicide (I used lime sulphur) and seal it with wax (I used silicone wax). If you do it properly, that will stop the die back of the bark, which will then gradually re-grow and cover the bare patches.

Lisa

Thank Lisa & Alpineart!!
Help alot. I think it could be both things...sunburn and fungus. I went to a nursery, and they recommend black "paint" product that i can paint on after i give the bark a good clean, as you Lisa, suggested.
Lisa, where do i get lime sulphur and silicon wax?

Thank again !!

Khanh