Pot. Makaha Enchantress Wine Bright yellow and black leaves and pseudobulbs

[Psych Chick]

Hello everyone,

I find myself in need of a bit of help concerning my cattleya (Pot. Makaha Enchantress 'Wine Bright'). I repotted it a few weeks ago using Pro Mix for orchid (only thing I could find- before it was Fafard's orchid potting mix). About a week or two ago it started losing leaves and turning brown-black and yellow, both the leaves and the pseudobulbs. I researched it online but can't figure out what is going on exactly , so I was hoping for some more expert eyes to help me out on the cause so I can apply the proper treatment and hopefully save it.

Thank you!

[Optimist]

Oh, those p-bulbs are rotted, or soon to be. I do not think that is natural scenecence (death of part of the plant). That would have a very obvious line in which the leaf is bright yellow, and the bulb is still green. I've had a few rottenbulbs. I just cut them off where it is no longer squishy. What sort of drainage do you have? A net basket would be better for them. In Canada, because it is so far from the equator, and I assume also very cool, or misty (look at me, I have never been there!) anyway, they would need a ton more drainage. At that store were there any baskets for water plants or aquaponics? Those with lava rocks, or extra chunky medium would be better. Then, of course the 2000 fc/ or equivalent. 2000 is just "beginning" catleya light. They often will not bloom unless you can get the light up to about 3000, and yet still not burn the leaves. When a cattleya is "happy" (in the correct light) it is light green and some have speckles of red on the leaves.

[Sharon's Sheepdogs]

I really can't determine what rot your orchid has developed because your photo is not clear enough. However, it appears one of the pseudobulbs has turned dark and if it feels soft or mushy, I suspect you have a fungal disease. The fungal disease is probably Black Rot, pythium or phytophthora, spread by oomycytes which can only travel in water. You should take steps immediately to save your orchid because this fungus spreads quickly.

First, make sure you isolate the orchid away from your other orchids. Second, you need to cut the infected part of the orchid off. Sterilize your cutting instrument with heat before each cut you make. Continue to cut until you no longer see any brown discoloration. At that point, I would pour hydrogen peroxide over the cut & apply sulfur or cinnamon to seal it. You must do this for three days in a row.

Do you have a broad spectrum fungicide safe for orchids that you could also spray your orchid with in addition to the peroxide?

You should throw out the medium the orchid had been potted in. Wash the pot with soap & water and then soak it in a solution of 50% water & 50% bleach for at least 24 hrs. If it appears the rot has stopped after treatment, you can repot.

I'm not familiar with the size of the bark contained in the Promix you used. However, you may need something larger so that the medium dries quicker although I'm not really sure what the source of the fungal infection was.

If you google "The Ruinous Rots", a pdf from The St. Augustine Orchid Society should come up. It is an excellent article and I think you will find it very helpful. If you also go to their website, you will find additional information & photos regarding this fungus.

If your orchid continues to develop symptoms and/or it has spread to your other orchids, let us know. You may need to begin using a systemic fungicide. Good luck!