Scottish Rock Garden Club Forum
Specific Families and Genera => Pleione and Orchidaceae => Topic started by: Graham Catlow on June 22, 2014, 07:43:50 PM
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Hi,
The first image looks great but what lies beneath?
This situation is all over the garden (I have a lot of Dacts) not just isolated. What do I do :-\
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Oh my goodness, that's a nightmare Graham - I've heard that others are seeing it again in their gardens. There's a discussion of it here :
http://www.srgc.net/forum/index.php?topic=566.0 (http://www.srgc.net/forum/index.php?topic=566.0) which includes a link to a Journal article the Wilson's wrote about it.
We'd advise you to dig them up now, take off the new tubers which should still be clean - pot them up in clean compost and keep them in quarantine and BURN the rest.
Fungicdes have little effect it seems. :'(
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Thanks Maggi.
I must have a hundred plants in various pars of the garden. What a task :'(
Is it a specific Dactylorhiza fungus or are my Pleiones and Cypripediums at risk also. That would be a greater disaster than the Dacts.
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I cannot say for sure, Graham - others will know more - but we think it's just affects Dacts.
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I hope so!
Thanks again.
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They are so beautiful! I am so sory this happened to you :S
I hope you get rid of this nasty thing! fingers crossed ;)
regards
G
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Graham
I have had a very bad outbreak of this disease in the past and see it has appeared again this year.
I tried taking off the new tubers but this proved no good and also doused them in every available fungicide,they are already infected and only prolongs the agony for another couple of years.
It wiped out my total collection all of known provenance.
The only positive side is that seedlings seem to spring up all over the garden and will recolonise.
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I am in the process of losing most of my dact collection also. The best were stolen during the winter, the rest have been battered by the weather. I think that it is the physical damage that lets the fungus, if that is what it is, into the plant. When I only had a few I grew them in pots, protected in a greenhouse and never experienced anything like this. It is only since my collection increased and I started to grow them outside, exposed to the elements that such problems started. I have inspected some of the new tubers and they are still small, some black, so I will destroy the lot.
I had decided to give up on dacts altogether, then went to the Malvern International Orchid Show last week and wound up coming back with some newbies. They are now being quarantined, for their own protection.
Unlike Tony I have no hope of seedlings in the garden. The soil must simply be too dry, stony and devoid of the necessary fungus for I have never had a single plant appear in over twenty years of growing dacts. They appear in other pots, but never in the ground!
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Do you think there's something amiss this year? It's started to take mine too... I just lost my beloved fuchsii, it's been wonderful, came up looking super in the spring and now it's gone. I've cut it down and hoped it might recover from underground. In other containers elsewhere in the garden they still look unaffected so I'm keeping my fingers crossed. Nightmare...
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In Lincolnshire at least, we had a ridiculously early spring which prompted growth, no late frosts worthy of mention, but alternating high temps and monsoons throughout late May and into June, with more rain in a couple of weeks than throughout the winter. My bigger, leafier plants were left looking like they had been through a grinder. They are the ones which have suffered. Smaller plants seem fine. My newbies will definitely be getting some form of protection next year, similar to my cyps.
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Your responses are just confirming my worst fears - hence the title of the thread.
I will do everything I can to see if I can bring at least some of them through it.
I always cut the spent flower heads off so no chance of seedlings
Graham
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I've been hit also. I also agree it is weather related ie battered stems and leaves lets in the fungus. My variegated fuchsia got it last year and failed to come up this year. I bulked them to 4. I should have let two go for security.
So far is doesn't affect the southern marsh orchid
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Graham and others, I do feel for you with this awful disease. As a crumb of comfort, Dac. 'Harold Esslemont' has a high resistance to Cladosporium orchidis. I would suggest however, that you get rid of as much of your diseased stock as possible and don't be in too much of a hurry before planting again. Dac. 'Harold Esslemont' is a robust plant and a good 'doer'. We were given a single tuber of the then un-named hybrid by a mutual friend of Harold's. We eventually sent tubers to the late Kath Dryden who named it after Harold and put it up to Joint Rock where it was awarded an A.M. It is available from some nurseries, but is still very expensive.
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Hi Maureen,
I have Harold Esslemont which originated in your garden from Bill and Helen. It is a couple of meters away from the others and as yet is unaffected. It will be interesting to see how it goes.
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I had a few affected last year and more this year. Some have gone completely. 'Harold Esslemont' which I bought two years ago is still looking fine. I thought Dactylorhiza purpurella was immune but it is not.
These two appear to be afflicted with something different.
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Dactylorhiza that spent the winter in my greenhouse on the floor, and moved out in spike, have showed no symptoms - fingers crossed
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My four variegated D. fuchsia failed to come up this year :'( :'( I'm blaming the heat and drought last July
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Sadly it is not just cultivated dacts which are suffering. In 2013 Gibraltar Point nature reserve near Skegness had the most amazing display of dacts that I have ever seen, way over one hundred thousand plants. The tidal surge last winter wiped out the population on the freshwater marsh. Those in the dunes have been struck by fungus. Samples have been sent for analysis and it will be interesting to see the results. The chief suspect is not Cladosporum but Ramularia.
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My four variegated D. fuchsia failed to come up this year :'( :'( I'm blaming the heat and drought last July
Did they just fail to come up or have you totally lost them, Mark?
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failed to come up. Not even a nose came up. I've resisted digging a hole just in case there is something there. I should have shared one or two for insurance
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I thought I would give you an update from last year when I lost my Dactylorhiza to the dreaded black death.
I took Maggies advice and dug up a large group of the infected plants up and removed the new tubers. I then soaked them in a solution of 2% household bleach for 24 hours. Nothing ventured nothing gained :-\
They were then planted into a general purpose compost and I hoped for the best.
I now have a group of what appear to be free of the disease. Has the bleach treatment worked or would the tubers have been disease free when I took them from the old plants?
What ever the answer I am pleased to have saved some.
Photos -
1. last year
2. removed tubers
3. this year
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The baby tubers do look nice and clean - and all seems very well now. Don't you love it when a plan comes together?!!
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Fantastic
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Maybe I'll try it with a couple of mine. I see new ones appearing elsewhere and they look ok so far, but most of my older ones have gone. Funnily enough the fuchsii that had the best spots of any came up looking ok at first and have flowered but now show signs of the disease. Those are the ones I shall tackle first!
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I now have a group of what appear to be free of the disease. Has the bleach treatment worked or would the tubers have been disease free when I took them from the old plants?
What ever the answer I am pleased to have saved some.
Graham
from my experience the new tubers were always diseased and this was obvious just by looking at the dormant growing point which was black. Yours look very healthy and I would say you have sorted the problem.