Black spot on cattleya pb

[luvmyorchid]

I've just noticed this black spot and 2 black eyes on one of my pseudobulbs. Can anyone tell me what it is? I have had this catt since June and use distilled water 30 10 10 every week quarter strength with a flush once a month. In December and January I did add epsom salt to 2 of the waterings. I have several other catts and they don't have any spots.

[SouthPark]

Originally Posted by luvmyorchid

I've just noticed this black spot and 2 black eyes on one of my pseudobulbs. Can anyone tell me what it is? I have had this catt since June and use distilled water 30 10 10 every week quarter strength with a flush once a month. In December and January I did add epsom salt to 2 of the waterings. I have several other catts and they don't have any spots.

Did it occur abruptly? Sometimes it can be due to cold-bruising. But - just in case - application of a systematic fungicide suitable for orchids might be beneficial.

[luvmyorchid]

Yes it happened in the last 10 days or so. We did have below zero temps here for a few days and it is closest to the picture window but not touching the glass. What kind of fungicide do you recommend? Thanks for the response 😊

[SouthPark]

Originally Posted by luvmyorchid

Yes it happened in the last 10 days or so. We did have below zero temps here for a few days and it is closest to the picture window but not touching the glass. What kind of fungicide do you recommend? Thanks for the response 😊

I see. Make sure to keep the orchid in an area where the temperature doesn't go below say 13 degree celcius. Some orchids can handle lower or much lower - but just some rough rule of thumb is needed at least.

Your orchid might have gotten through this, and might be just fine. But - if you have time later, consider fungicides like mancozeb, agri-fos, and thiomyl.

[bogdan]

That looks like rot. I would cut that pseudobulb from the base until I see no more black tissue and put cinnamon on the wound, then use a Mancozeb fungicide on the entire plant. The others that were recommended are also good, especially Aliette.

Also add some tap water once in a while (at flushing time, for example) or fertilize with a calcium containing fertilizer.

[Merita]

That happened to me with a cattleya that was going to take out the pod. I cut two pseudobulbs and thoroughly clean the rhizome part, change the substrate and disinfect everything. For me it is a fungus that is going up so I am still applying thiomyl since it came out in another pseudobulb. The plant has continued its growth but more slowly and that dead part that is seen, was not deep or soft. For now I will not cut anything else, I hope that the fungus does not continue walking. This was 11/11/19, you can see it at the beginning in Beginner discussion, page 7