Black blotches showing up on R. Digbyana
 

I got this orchid about 2 months ago at a show. It's been doing quite well, and has even started a small new psudobulb growth.

About 3-6 days ago a black blotch showed up on one of the leaves. I had moved it to more sun, so I figured maybe a little burn or something, not being incredibly familiar with growing R. Digbyana. This morning, the leaf with the initial black blotch also has a large amount of blackening on the lower bulb. I've also got another leaf with two black spots forming! I need to stop this all now. This orchid was an expensive birthday gift.

R. Digbyana issues - Album on Imgur

Since this was a fairly recent purchase, is there a chance that you could contact the vendor? This kind of problem was probably getting started when you got it. If you can't work an exchange or refund, you'll need to treat aggressively

It looks like rot got into a pseudobulb - time for surgery, because this sort of thing can progress rapidly. Get it out of the pot, and be sure that you work with sterile clippers.You'll probably see black on the rhizome. Remove that black p-bulb for sure. If you see black on the rhizome, you'll need to continue to clean tissue (which means removing more p-bulbs) If you can get it back to clean tissue, new eyes will pop and the plant will regenerate itself with "tincture of time"... patience, But Catts in general can be susceptible to this... and an apparently healthy plant can go down fast.

I only found one psudobulb with no black spots. They all had some black when I removed the potting medium. Thankfully I had one good psudobulb, and it's got new growth arriving. Everything was doused in fungicide after being mounted, bareroot to cork bark. I think I'll gently wrap some spanish moss around it to keep the humidity higher.

I don't think I'll ask for any sort of refund or exchange from the seller. I think it was just an important lesson to always repot and check the plant if there is any doubt. Now I think I'd just like to order an awarded division and grow that. Go big or nothing for round 2.

The seller may not have known either. This sort of rot that gets into the rhizome has a nasty tendency to only show itself after it has done a lot of damage. With a new growth starting on the part that is clean (hopefully, no black on the cut surface of the rhizome) , I think the plant will do fine. Fortunately, Rl. digbyana is a vigorous grower. But this can happen to any plant, no matter what the pedigree (and it happens to the best of Catt growers - I am not one of them, but I have friends who are much better at it, and they cry on my shoulder) ... quick action to cut away the bad stuff is the plant-saving step.

Your media could be too moisture retaining for South Florida. Rlc digbyana does best when in a medium that dries quickly after watering. If left moist too long, it will develop root/rot issues.

I have mine potted in leca, in clay pots. Lots of water at this time of year but quick drying. Less water in the winter...allow longer stretches between waterings.

I grow mine mounted for this reason.

Mounted would be perfect too. For me though, I'm out of space for larger mounts and dig is a very neat and orderly grower...fills a pot very nicely without trying to overtake the neighbors...unlike glauca - the rampant root monsters.

For Catts in general that would be happy mounted (L. anceps is a biggie) , I am starting to use wood baskets with large bark quite a bit. The roots grab on like they do on a mount, it dries fast, and they stay a little more controlled. I think of the wood basket as a three-dimensional mount.