Cymbidium bulb rot and yellowing leaves in Semi-Hydro.

[empiref]

Hello,

One of my cyms started to show some signs of trouble about 3 weeks ago.

When I first got it, it had 3 bulbs that were loosely attached to the other 5 big bulbs, the cym was in flower, i had 2 flower spikes and bright green flowers.

The trouble started with signs of yellowing leaves on the loosely attached bulbs, 2 mature ones, the leaves started falling off one by one, in an interval of couple of days between each, until the bulbs had no leaves left. (the entire leaf would get yellow, then dry brown then fall off). After the leaves would fall off, the bulb would turn to brownish yellow dry color at the bottom, then i'd twist it, remove it, throw it away, and then sprinkle some cinnamon powder on where the bulb was attached.

It also had a new growth which started shortly after I moved the cym into semi-hydro. Today, I was checking on it because it had a yellowing leaf on the outside, and suddenly the bulb snapped off and leaves were broken off. I unpoted it, removed the base of the bulb and sprinkled some cinnamon powder for about 30 minutes before I repoted the other bulbs again.

The foliage of the other bulbs are green and the bulbs are solid-firm to the touch and not soft, although a new growth is a big soft at the base, but I guess it's because the new growth hasn't matured yet.

All my cyms are placed outside, and has been in the same place for the last 5 months. they receive about 7 hours of direct sunlight a day, 3 in the early morning and 4 in the late afternoon until the sun sets.

I water once a week, by flushing the entire pot, the reservoirs are never empty and use a well balanced fertilizer weekly weakly, in addition of Kelpak every 15 days.

I have attached pics below, your opinions are well appreciated because I don't want to lose my cym.

Thank you in advance.

[WhiteRabbit]

I wonder if there is some type of infection ? Hopefully others will have some opinions/advice for you. Good luck!

[Cym Ladye]

I suspect your plant has developed crown rot. Smell the bulbs. You will detect an abnormal, rotting smell. It is very difficult to stop crown rot, but if you cut the connection starting with the worst bulb and continuing until you see a clean cut to the next bulb, you may be able to save the remaining plant. I know of nothing, at least nothing I have tried, which will stop this.

Cym Ladye

[empiref]

Originally Posted by Cym Ladye

I suspect your plant has developed crown rot. Smell the bulbs. You will detect an abnormal, rotting smell. It is very difficult to stop crown rot, but if you cut the connection starting with the worst bulb and continuing until you see a clean cut to the next bulb, you may be able to save the remaining plant. I know of nothing, at least nothing I have tried, which will stop this.

Cym Ladye

Hello Cym Ladye, I have smelled the bulbs and there's no 'abnormal, rotting smell'! and the smell is the same smell of all the bulbs in the 3 other pots. However before you answered I got some Hydrogen Peroxide 30%, and used it at 5% per liter of water and flushed the pot.

In your vast experience, what is the reason for crown rot?

I guess I just have to wait and see, and will keep updating this thread.

Thank you for your time.

[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

[james mickelso]

For my money it is rot caused by being too wet. It rots the oldest bulb then keeps on killing until the whole thing dries out. The leaves turn yellow and the bulb rots from the inside bottom out. Cut off the oldest bulb, checking the rizome and keep cutting until there is no visible rot inside the rizome. Dust with cinnamon and repot in a loose coarse media. Cyms do not like wet conditions. I've had lots of this happen to my cyms when I first started growing them. Yes many can grow in dirt but not wet dirt. Pythium and phythora are the culprits. Laso the roots become hollow and dead but unless you squeeze them you don't know it.