BLC Ports of Paradise issue - need disease ID help

[smokinjoe1952]

I was out of town for about 10 days, and returned to find my BLC had this issue on 3 new growths. New meaning the most recent growths in the last 6 months. There were no issues like this elsewhere on the plant. I have included a pic of the 3 growths I cut off, and the remaining plant. I did my research, but found nothing definitive. This seemed to happen rather suddenly, but It had probably started before I left.

I would ask:

1. What is it?
2. Should I do anything else besides cutting off the diseased growth ?
3. How contagious is it?

Thanks,

SJ

[Gthumbz89]

I am no expert but the fact this is happening on new growths suggests to me it might be calcium and magnesium related. Do you check your nutrient feed ph after it runs through the pot?


Other than that it could be bacterial, fungal or environment related [cold damage, adema, sun burn]. It takes some detective work to tell for sure.

Some questions to ask are: is my plant exposed to moisture with bad airflow, what footcandles is it receiving, what temperatures are my water,environment?
Is my nutrient feed at a bad ph resulting in deficiencies so on and so forth.

Looking for pests is good too.

Hope this helps. If you can answer some of those questions on this thread others can help more also.

[smokinjoe1952]

More info:

grown in an enclosed chamber
temp d/n - 67-80F
hum. d/n - 65-77%
constant circulation with several 12v fans
outside air (room air) vented in for 3 minutes every 3 hours
no sign of pests
use distilled water, but use JACKS and Rays SOLO product. Both have calcium and mag. Both are for pure water.
LED lighting dimmable and set to the proper range for Cattleyas 12 hours on/off cycle
planted in s/h as shown

That's about all I could think of. Hope it helps.

SJ

[bil]

Looking at the roots, I would so repot that.

[Fernando]

Black rot. Often seen in Cattleya, precisely in that Psbulb stage. Very quick sometimes. Highly infectious, so:
- separate this plant from others
- never touch it and then touch other plants
- keep a strict quarantine protocol

now I would say, don't water for a long while, until nothing goes black, but I see this plant is in sh, and that I don't know. I've had this disease, too, and left my plants for months bone dry. They recovered (though look a bit ugly, Bc. Maikai and R. dygbiana).

Remaining water in the sheets enclosing the young Psbulbs may be a beginning, also a heavy drop in tº; or a newly acquired plant that comes from hot, optimal surrounding to another, too much fertilizing, organic fertilizing ... week tissues as this young, not mature psbulb always have is mostly infected, so more Ca won't help at this stage.

Luck with your plant.

[smokinjoe1952]

Fernando,

Thanks for your diagnosis. After further reading it sounds like a very serious disease. I will remove the plant from my grow chamber, and see what happens. I have now read more than 1 article that recommends discarding the plant if it is not valuable, which this one is not.

SJ

[Fernando]

The 'rest' of the plant looks very healthy. So, if you have a place to keep it apart from the other orchids, try a very dry and ventilated situation for a couple of weeks before discarding the plant!

And if it recovers after a few weeks or even months, first thing would be re-pot and cutting away everything which could be dead, formerly infected tissues, keep dry until new roots form and then go back to your normal watering.
Luck!

[rbarata]

I have now read more than 1 article that recommends discarding the plant if it is not valuable, which this one is not.

That's running away from the problem and avoid a great learning experience.

[smokinjoe1952]

I thought the lesson was "keep it isolated" so as not to infect your entire collection, but you are right, there is more to be learned if this plant can recover. I have it isolated in the normal conditions of my home which is about 35% humidity, and temps from 68 - 74F.

The remainder of the plant looks healthy, so I am not sure when to consider it "recovered" and able to rejoin the group in the chamber. It already has 3 new growths starting, so I will allow those to grow to at least 3-4 inches long, and see if they exhibit any symptoms.

Does that sounds about right?

I recently increased RH from 45-60% d/night to about 65 - 78% d/night. I have good circulation in the chamber but was wondering if the recent rise in humidity can cause this.

I can easily reduce the night time RH to about 60-65%, but was told that 77-80% is not too high.

I have catts, oncs. Phaphs, Phals and Phrags in the chamber. All of the plants seem to be doing better after the rise in humidity 3 weeks ago, so I don't want to reduce it if the night time % is not in the DANGER zone.

Comments on my RH would also be appreciated.

SJ

PS - Love the smokin fast forum!!

SJ

[Fernando]

RH is OK.