Treating the orchids in my sickbay: Zygos, a Phal, and an Angraecum
 

Hello All,

I am keeping a few orchids in isolation due to issues that have got me stumped. Right now they are in my “Orchid Sickbay”.

Ideally, I would like to be able to reintroduce them into the greenhouse but I want to know if it is safe to have them around other plants and I also need to know the correct treatment for each one.

There are five plants in question: Four Zygopetalums (three with leaf spotting, one with a bulb rot), one Phal, and one Angraecum. I will start with the Angraecum didieri.


1. I broke the spur on the flower of this Angraecum didieri while repositioning the flower as it was blooming into the medium. Is that a serious problem? I did not think so.

2. This Phal pictured below has some very unsightly spots. Both lighter yellow spots and darker ones. It was like this when I bought it at a show several years ago but has only gotten worse as there weren’t so many spots on the newest leaf.

How should I treat this one? Is it likely contagious? Should I keep it in isolation? The vendor when I bought it insisted it was cold damage but I am not so sure now. Could it be something serious? What should I do with this one?


3. This leafless Zygo has rot on a backbulb but also the start of new growth on a different bulb. I am worried the rot will spread to the healthy bulb and new growth and kill the plant.

Sometimes, I have noticed that rotting back bulbs will rot and dry up and not spread to the good bulbs, which is even better since it makes a more sealed off area. Should I cut off the rotting bulb or leave it? How should I cut it? Should I repot it into bark? How should I go about saving this one? It is very valuable to me.

I had cut off another rotting bulb several weeks ago but it just advanced anyway to the one here. I don’t want to lose this one. As everyone probably knows, I have many fungicides at my disposal.



4. These three Zygopetalums have significant leaf spotting. If it were another kind of orchid I would be more concerned about viruses but since they are Zygos, I am not as worried. The smaller ones have new growths that appear to be clean but how do I stop this from spreading? Should I be worried about the health of these plants at all?

I know Zygopetalums are prone to leaf spotting and I certainly don’t grow them for their foliage. I just want to make sure the plants are being hurt by it and it isn’t a dangerous contagion.

I am investigating some probiotics to deal with it. I think it is caused by water droplets sitting on the leaves but I am not sure. They were mostly sitting near the ground so water probably did drip onto them.


I can also post additional photos (in different angles/closer shots) if that would be helpful.
Thank you all.

FWIW. I had two phals like that. Ray told me it was cold water damage but, on one it did spread. and and I pitched it. The other I cut a leaf and so far so good. I also had a white Equestris that was treated w probiotics and that helped but didn't cure black pitting.

The zygo leaves look much worse than I would expect as the older leaves get bad and fall whilst the younger ones are clean. I spray mine with amber Listerine regularly. If it doesn't clear up, I'd dump it too.

The pbulb, no opinion.

With the Phalaenopsis, I’d be curious about virus. I’m not sure about the Zygos. Mine have ugly foliage, but nothing that extensive. Maybe see if a lower humidity, higher air flow environment helps? For the back bulb, I’d be inclined to remove it. These types of rots have usually ended up spreading on me.

Looks to me like you're dealing with acidovorax, a bacterial infection closely related (synonymous, to some) to pseudomonas infections.

It is very easily spread by water splashing, but may also easily be prevented by use of a topical disinfectant like Physan.

It may be treated with the use of copper compounds, like Phyton 27 or Southern Ag Liquid Copper.

It looked like that kind of bacterial brown spot to me also.

My only other concern about the cause was cymbidium mosaic virus as that looks similar.

I do often spray my plants with physan, but it seems I got it anyway.

I would hate to have to get rid of any plants just because of that. The phal I was a bit worried about viruses but I think it is the same bacterial spotting too. Thankfully, zygopetalums are deciduous so I just have to make sure it doesn’t spread to the new growth. I am glad it hasn’t spread around much in the greenhouse either.

I am a bit concerned about using copper around the Dendrobiums. Is there a good way to make sure the Dendrobiums don’t get exposed to too much copper when I use it? Once the zygo orchids have been sprayed with copper, can they still coexist in the GH with the dendrobiums?

Also, I don’t have Phyton but I do have Southern Ag liquid copper. How much per gallon is a good choice?

Maybe I will also spray with cleary’s since the dry, sunken, papery black areas also remind me of fungal spots.

That's probably a great call. Copper sprays can certaintly stop that sort of thing in their tracks.

I do hear that some thin-leaf plants can have issues with copper (or even particular plants like Dendrobium) ------ but hard to say whether that's true or not ...... or if true ---- applies to all thin-leaf plants.

But I also recall at least 1 person online saying that there shouldn't actually be a reason that thin leaf plants and Dendrobium should be negatively impacted. So it may just be a dosage thing.

I'm going to test on a Dendrobium ------ and see what happens. I'll choose a moschatum to try it on.

I know I’ve read in many places that said no copper for dendrobiums but that’s all I’ve ever seen.

Brassa ...... thanks for letting me know you saw those details too. I'll try some copper spray on one of my super healthy moschatums ----- and see what happens. I'll use an appropriate dose. Even if it turns out ok for this particular one ----- it won't guarantee that it'll be ok for other sorts of Den. I only have 3 types of dendrobium in my collections ----- moschatum, discolor and devonianum.

Simply don't spray them! There is no transfer, plant to plant.

The label specifies 2 teaspoons/gallon, repat at 7-14-day intervals.

Copper is also a fungicide.

Don't forget that these treatments are not innocuous to the plant. Keep treatments targeted and minimized.

We always used Captan to control fungus issues with the fruit trees/grapes and roses. It is pretty powerful stuff and you probably want to wear a mask, gloves, and shower very well immediately after using. There are formulas with and without copper.


Robot Check

Here is a good place to look, too:

https://www.staugorchidsociety.org/P...ySueBottom.pdf