Dendrobium Spectabile leaves with dark sunken spots

[dickinson.mead@gmail.com]

I just got this young Dendrobium Spectabile and it looked just fine. The next day I started seeing dark sunken spots on the newest growth leaves. The spots started on the tips and moved inward. The next day the had doubled in size and also started on the next newest growth leaves. I trimmed the involved leaves and doused the edges with cinnamon. That was yesterday.... today, I see this (see images) It has started again on more leaves. I have sprayed it down with hydrogen peroxide and I don't know what else to do.

[WhiteRabbit]

Could it have gotten too cold?

[dickinson.mead@gmail.com]

I got it from our local Lowes, a bag baby... one of the reasons I bought it was because it looked so healthy and had nice strong glossy new growth. I put it in my sun room which never gets below 65 degrees because my parrots also live there. I had planned to acclimate it in stages to my back deck that's shaded by a sun screen panel. It's had late afternoon medium-strong light filtered through a screened window for the three days I have had it. It was inside the air conditioned building at Lowes though, not in the greenhouse. I can't imagine it's below 68 to 70 degrees in the store though.

[estación seca]

I don't know what it is, but I would treat anything moving that fast as a bacterial rot. Hydrogen peroxide is for surface issues, which this isn't. The only way to cure something like this is with cold steel. These things are often spread via water, so be sure no water splashes off this plant onto other surfaces.

Take it out of the pot and remove all the potting medium. Cut off everything bad, far behind the demarcation line. Sterilize your blade with heat or bleach solution between cuts. Take off more rather than less. You may need to cut far into pseudobulbs. Orchids are tough plants; a small plant with no rot will recover, but a larger plant with remaining rot will not. Treat all surfaces as though infectious, and wipe down everything with 10% household bleach in water.

Let the plant stay dry for a day or so, then repot into fresh medium. Water it gingerly for a few weeks. If it's going to recover, it will begin growing again. If it's going to die, it will probably happen soon.