SOS: Rot and tissue collapse on Rlc. Ports of Paradise.

[BrassavolaStars]

Hello all,

I was in my greenhouse today when I noticed significant issues with this plant. The leaves are falling, there is tissue collapse on the leaves, and a pseudo bulb is mushy at the leaf joint. Much of the leaf damage is to the underside only.

What do I do? Is it black rot? Sunburn? Cold damage? Virus? The greenhouse got down to the lower 40s in the spot where it was but nothing else seems impacted. I have fixed the heater now so it won’t get cold again. It was also in an area not protect well by the shade cloth also. It is also a relatively new plant. What should I do?

[SouthPark]

Maybe apply some copper spray ------ or monterey garden-phos spray ----- to leaves (all parts) and stem too. And then maintain suitable growing temperatures and provide some gentle air-flow in the growing area (via fans etc). And then monitor the situation. Hopefully the orchid can recover. Are there any bulb and leaf combinations that appear unaffected?

Also - for the pic uploads - try making the images larger if possible. The 283 pixel wide by 378 tall are kind of on the relatively small side.

All the very best! Hope this one makes it and recovers!

[Ray]

Looks like cold damage to me. Too extensive and too quick to be much else in the circumstances.

The best option, in my opinion, is to remove any discolored tissue, dust the wounds with cinnamon, and treat it better.

As unfortunate as it is, this is doing a lot to move you on down the learning curve to becoming an “expert”.

[Orchidtinkerer]

I noticed I'd lost a leaf on a dendrobium today. Least Dendrobiums are designed to lose leaves, that poor P of P looks in a sorry state. I want to get my P of P to flower so it is getting pampered at mine, 65F minimum.
I know it was probably an accident so I hope you can keep it alive.

[Roberta]

I agree with Ray that cold is the likely culprit - there are plenty of Catts (and other things) that tolerate temperatures in the low 40's. but possibly not this one. (It's about 1/3 C. dowiana, which hates cold... half is Rl digbyana which should tolerate it, but the combo maybe not so much) Also, was it it wet when it got cold? That can make a plant more vulnerable. This time of year, as far north as you are, I'd doubt sunburn as an issue. Take Ray's advice on surgery and keep it warmer.

[ArronOB]

Just to put the issue of winter lows and hybrid cattleyas in perspective - I grow about 50 hybrid cattleyas outside year-round. We had a particularly cold winter this year with temps down to 6 degrees Celsius on several nights. About 5 of my catts experienced cold damage - which looks just like yours with the cellular collapse in a reticulated pattern. Usually collapsed and dimpled on one side of the leaf and just blackened on the other. Nothing none of the others were impacted.

My solution for the affected plants is a trip to the council green waste bin. I don’t have any tolerance for plants which can’t cope with the conditions nature provides.

FWIW I also keep about 50 oncidium hybrid types. One of those appears to have received cold damage. In their case it’s just random black patches on the leaves. Unfortunately it’s a noid so I can’t work out what it’s parentage is and why it is the only plant that should be affected.