Juniper Blight

[Robsterios]

Hello.. Would love to hear different views on what people do to prevent/treat Juniper Blight.
I have used Copper Oxychloride and have been advised the use of Mancozeb plus. I have a rather old Squamata that has probably got it although I'm not entirely sure, it could just be generally unhealthy but unknown for what reason. It has lived in it's spot for years in full health but had declined over the recent year.. It also got blown off the bench in a massive storm we had back in Jan. while I was in Japan smashing the Tokaname it was in but my wife slip potted it to save it..
I have a good understanding of their requirements regarding conditions, eg; good drainage, airflow, light etc.. I've only just gave it a big cleanup and cut back as per the photo's.
Anyway, it's worth saving if I can. Any advice would be great thanks..Rob.

[treeman]

I'm thinking the best course of action is the preventative one. That is - fertilize well and regularly to allow it to build up it's natural defences, and spray the fungicides regularly whether you see it or not. Spray once per month with pesticide as well as they may be carriers and spreaders.
Once the tree has been affected it seems a lot harder to bring it back. You should dip the blades in alcohol (or preferably heat treat over a flame) between each cut or to stop potential spread. (that can be a lot of dipping I know!) Then spray the whole tree with mancozeb or bordeaux or something similar after working on it.
I have a shimpaku which is affected. As an experiment, rather than burning it I cut off all affected parts I could see, even the ones slightly off colour, until all that was left was apparently healthy growth. Then I sprayed it well with a mix of mancozeb and a systemic fungicide. The problem returned. Not an all parts. Most of the plant is perfectly healthy but some branches are almost dead. This means that the organism is actually in the sap and moves about that way. Why it doesn't affect the whole tree is a mystery. Mancozeb is not systemic and I don't think spraying systemics (if you can get them mind you!!) will be very effective due to the waxy covering on juniper foliage. Mancozeb is broad spectrum so it will probably kill the disease but only if it comes in direct contact with it. What we need is a chemical which we can drench the roots with so the plant can take it up properly. It must be specific to the particular disease or it won't work. I don't know of such a chemical yet. We don't even really know what the disease actually is yet. It might be juniper tip die back or it may be cypress canker - which is very common in Vic - and which also affects junipers. It's also possible that it spreads from other species of tree in our collections which don't show any symptoms or have different symptoms??
Also might be worth trying to spray cinnamon with a wetting agent or dragon's blood like they do with orchids as a preventative?

[jonathansanchez]

Very useful information! It has helped me a lot. Thanks for sharing it!

[MJL]

Hey Rob, I'm just letting you know that I am envious of your set up. You have lovely clean area for your collection and it looks like you can cover with shade quite easily too.

I wish... my bonsai are dotted around my garden which means I need to move them around a lot and try to manage different micro-climates and watering needs. Oh well ... gotta start somewhere!

Also, thanks for the info Treeman.