Dendrobium Nobile propagation and disease question.

[BrassavolaStars]

Hello All,

I had a few questions about a problematic dendrobium nobile hybrid.

This is a complicated post and I didn’t quite know which thread to put it in, so I posted it here.

I have this dendrobium nobile hybrid that had one cane, one new growth, and several dried-out cane bases. It was planted in moss and I watered it infrequently (only when fully dry). The humidity in its growing area is high (around 75%) and the light levels were medium. The new growth became hollow where is connected to the rest of the plant, blackened, and toppled over (pictures can be found in the prior post of mine about this orchid). Additionally, after removing the failed new growth, the old cane began to turn soft and brown in the middle (probably because this was the oldest cane). I checked the roots and most of them seemed fine however many of the cane bases had holes in them or were hollow. I have three questions.

1. What caused the original problem with this orchid?
Photos can be found in a prior post I made about this orchid.

2. I cut off the old (and only) cane just below the browning section and sprayed the wound with alcohol and Physan 20. I then removed this browning section (which turned out to be hollowed in the center) and saved the top section which was still green and firm and sprayed that wound with Physan and alcohol as well. I then sealed this wound where I cut the top from the middle with hot wax and placed this section (which had around 4 nodes and 3 dormant eyes) in a Tupperware filled with a layer of Physan (1 tablespoon per gallon) moistened moss. Will this section create keikis? I also intend to get keiki paste and apply it when it arrives.

3. What should I do with the rest of the plant which has healthy roots but no canes left except for the base of the cane I cut? It also has a softer, hollow section where the previous new growth that failed was. This section also has healthy roots (also visible in photos from original post). What should I do about this?

I can also add photos of the sections of the old cane that turned brown if that is helpful.

Thanks all.

Sincerely,
Brassavola Stars.

[Dollythehun]

At the risk if sounding harsh, you should toss the whole thing and buy a healthy plant.

Your inconsistent watering [I]might[I] have induced a bacterial infection. I recently had this happen. All plants contain pathogens, it's stress that causes them to erupt.

Learn what your next plant needs and then apply that.

[estación seca]

Deciduous Dendrobiums like Den. nobile hybrids should not dry out during the summer growing season. If they dry out the new growths quickly die. The older canes can make 1 or 2 more attempts at new growth, but if those also die from underwatering, the plant dies.

Edit June 15 2020:
Yamamoto Dendrobiums in Japan hybridizes and produces a great number of these plants. Their Web site formerly had excellent growing information for hobbyists. Unfortunately it is no longer there. You can still look at the varieties they grow, and maybe see one very similar to yours.

I saved the page, and summarized it in a post in this thread:
Uncertain if Dendrobium is still alive

Yamamoto now has a page showing how to force Dendrobium nobile for Christmas flowering in Japan's climate. There is a lot to learn from that page, but it is intended for growers who can artificially heat and cool their greenhouses during off seasons. Note they use coconut husk for growing medium, which many orchidists would say retains too much water for orchids. For many orchids that is correct, but this is a very thirsty orchid.