Cymbidium bulb rot and yellowing leaves in Semi-Hydro.

[Ray]

I think that "crown rot" is a bit of a misnomer in this case, as that usually refers to rots that occur when standing water is left sitting in the crown of a plant, most often phalaenopsis.

As your situation is apparently a rhizome-based infection, I would guess that to be a fungal rot - phytophthora or pythium, maybe. They thrive in high temperatures and humidity. A systemic fungicide is called for. I think Cleary's 3336 WP is one of the best, but don't know how readily you can find it. I have no experience with Phyton 27 (copper sulfate) on cymbidiums, but they are pretty hardy, so I doubt there would be issues. Cym Ladye can probably advise better.

[empiref]

Originally Posted by Ray

I think that "crown rot" is a bit of a misnomer in this case, as that usually refers to rots that occur when standing water is left sitting in the crown of a plant, most often phalaenopsis.

As your situation is apparently a rhizome-based infection, I would guess that to be a fungal rot - phytophthora or pythium, maybe. They thrive in high temperatures and humidity. A systemic fungicide is called for. I think Cleary's 3336 WP is one of the best, but don't know how readily you can find it. I have no experience with Phyton 27 (copper sulfate) on cymbidiums, but they are pretty hardy, so I doubt there would be issues. Cym Ladye can probably advise better.

Thank you Ray for your reply,

I think maybe i know why this happens, this cym was was potted a little bit deeper into the LECA and I have a habit of filling the pot all the way to the rims before flushing, and that way the bulbs were getting submerged in water before flushing.

Anyways, the 3336 WP and the Phyton 27 are not available in Lebanon. I'm still using Hydrogen peroxide and will keep using it every 5 days, and hopefully things will turn out ok. My other cyms are doing great.

Best regards,

[Cym Ladye]

Ray is correct in his comment on "crown rot" in Phals but it is caused by the same thing in Cyms. The rot starts with water held in the growth, usually the new growth, for too long a period. When the growth slows down, the leaves fail to develop and lengthen rapidly and what I believe is a fungal infection gets started. It can kill the plant or stop with the new growth.

As I was thinking more about your problem, the signs you showed could also come about if the growth were just slightly broken at that point causing it to then die the rest of the way. There would be no odor in that case.

The general look of the shriveled BBs on your plant tells me that prior to your getting it, it had undoubtedly been over watered to cause root death and the resulting shriveled bulbs. The poor plant was trying desperately to survive on the food stored in the bulbs!

Your goal now is to get new growths started ASAP with good culture, which will send down new roots to sustain the plant. Removing the leaves off the oldest bulb, especially if it only has two or three leaves, and thus converting it into a "feeder" bulb might help too. This way, the bulb could give all its energy to the rest of the division and not have to try to sustain its own leaves.

Good Luck,
CL

[empiref]

Originally Posted by Cym Ladye

Ray is correct in his comment on "crown rot" in Phals but it is caused by the same thing in Cyms. The rot starts with water held in the growth, usually the new growth, for too long a period. When the growth slows down, the leaves fail to develop and lengthen rapidly and what I believe is a fungal infection gets started. It can kill the plant or stop with the new growth.

As I was thinking more about your problem, the signs you showed could also come about if the growth were just slightly broken at that point causing it to then die the rest of the way. There would be no odor in that case.

The general look of the shriveled BBs on your plant tells me that prior to your getting it, it had undoubtedly been over watered to cause root death and the resulting shriveled bulbs. The poor plant was trying desperately to survive on the food stored in the bulbs!

Your goal now is to get new growths started ASAP with good culture, which will send down new roots to sustain the plant. Removing the leaves off the oldest bulb, especially if it only has two or three leaves, and thus converting it into a "feeder" bulb might help too. This way, the bulb could give all its energy to the rest of the division and not have to try to sustain its own leaves.

Good Luck,
CL

Cym Ladye,

Thank you very much for your advice, as you mentioned there was no foul odor whatsoever in the pot or on the dead new growth.

Today I watered my Cyms, and flushed the pot of the cym in question with a 5%/L or Hydrogen Peroxide.

There seems to be no deterioration with the cym, and today I found a new growth on it, between a new growth and an old bulb (hopefully it is a spike). I took your advice and removed the leaves on one of the oldest bulbs, which had only three leaves, and did the same thing on other cyms too. i got rid of the leaves on the bulbs containing two or three leaves to convert them into "feeder" bulbs like you mentioned.

New growth on the cym in question:


Before leaves removal:


After leaves removal:


Here's something I found on a different cym while watering, I thought these are flower spikes!!

[Cym Ladye]

The new growths look very strong so I think you may be out of the woods. I suspect that is a bloom spike but I would suggest, once it opens, that you cut it and let the plant put all its energy into growth.

CL