Dactylorhiza disease

[Frederik]

Hello
I have some orchids, dactylorhiza and orchis, in my garden. Unfortunately they have catched a very bad disease which I don't know how to cure. The main part of the infected plants die after the disease.
Is there anyone who knows this disease and how to cure it?
I have attached two pictures, so that you can see how it looks like.

Best regards,
Frederik Moeller,
Denmark

[Ian Y]

Hello Frederik
Many of us in th UK were affected by similar fungal diseases hitting our dactylorhizas a few years ago.
The good news is that it seems to have subsided now and our dactylorhiza plants are doing well again.
With our worst infected plpants I dug up the rhizomes and carefully removed the new young ones from the parent I disposed of the parent and kept the small young rhizomes which had not been infected.

I know some people planted the diseased plants in a far away corner of their garden and in time some of them recovered.

[Maggi Young]

The problem is caused by a fungal pathogen: Cladosporium orchidis. there is an article about this in "The Rock Garden" Journal number 107, June 2001.  The article by Brian and Maureen Wilson is on pages 168-170.

 Edited to add article in pdf: click to download....
  Wilson Dact._diseasearticle.pdf (256.11 kB - downloaded 729 times.)

[jomowi]

I agree with the diagnosis.  In my experience fungicides have little effect.  The only help I know is to replant into clean soil and keep the rain off the plants with a clear plastic sheet while keeping them well ventilated.

Brian Wilson Aberdeen

[Frederik]

Hello Ian Y, Maggi Young and Brian Wilson
Thank you for your help