Leaf problem

Is the plant still producing new growths successfully? I read that bean yellow mosaic virus can infect Masdevallias and lead to aborted new growths among other things. That's really just a shot in the dark though, so take it with a grain of salt.

 

This is certainly not a firm diagnosis, but my first suspicion would be fertilizer salts accumulation in the medium, or an imbalance due to overdosing something.

For example, N, Ca, and K can compete for sites within the plant, an excess in calcium or potassium can reduce the uptake of nitrogen.

 

Your plant is dying, you should give it to me for disposal, unless it's a cool grower, cool growers will destroy the harmony of my compost pile .

 

Your plant is no longer dying and my composting services are no longer available.

 

I don't know what test kits are produced in the EU (given the size of the orchid-producing industry especially in the Netherlands I strongly suspect that someone is manufacturing these) but Rega Biotechnology in Taiwan sells them (for ORSV and CymMV) and ships internationally - the down side is that the minimum order is 50 tests, but perhaps you can get a group together to share. The various bits of the test (buffer, strip, mixing stick) are packaged individually so the package of 50 is easy to to divide.

(The underlying technology of the orchid virus test kits is the same as the COVID tests that we all have come to know and love... Whether tests are manufactured for any particular virus is only a matter of demand - and therefor economics.)