rot on new growth

[ssdraves]

this is my first time here. hope someone can help.
new growth on my cattelyas seems to succomb to rot.
sometimes black and sometimes brownish.
i have adjusted my watering, changed mediums, thrown out infected plants
and it still keeps happening. not sure what to do next.....
any suggestions??

[Shannara]

It could be black rot or soft brown rot (my guess is black rot but without a culture I can't be sure). Either way you always want to quarantine these sick plants from your collection. Get a sterile blade....locate the first healthy growth next to the rot and cut off the rotted growth and any p-bulb they are touching. This stuff can spread quickly through the plant so you want to cut at least an inch or one healthy p-bulb back from where you see the rot. Don't use the same blade to cut twice unless you sterilize it with a propane torch or bleach/fungicide. I prefer to use X-acto blades, one for each cut so I don't spread this stuff.

Rub the wound with either cinnamon or a fungicide. Keep it isolated for at least a month and watch the p-bulbs near the cut to see if it continues to spread. This kinda of stuff spread via water so don't let this guy drip on anyone. Closely watch any plants that were located near this one. Also try and avoid getting water on/in the new growth. If water is allowed to stand or puddle on your plant then you risk creating conditions perfect for water mold fungus (phytophthora to take hold). Make sure your watering early in the day and not too often. Lots and lots of airflow to help your plants foliage dry out quickly after watering.

HTH and good luck.

Shann~

[FLBob]

One problem that I see affecting new growth on cattleya is calcium deficiency. The newly developing tissues will turn black. Normally the pseudobulb will remain unaffected though.

[Leafmite]

Brown rot often starts when water sits in nooks and crannies of an orchid, in cooler weather. Cattleyas are prone to black rot. Last year I dealt with a fast moving brown rot on one of my cattleyas and this December, I just went through black rot with many of my cattleyas and a brassavola. I have been told that it helps to have the rhizome above or level with the media (the few that didn't have problems are either mounted or were planted on top of the media. These diseases can move pretty fast without quick action.
Leafmite

[Leafmite]

Yes, I also heard that calcium helps and added a little oyster shell to my cattleyas last month. I think that living somewhere tropical would help the most, though.
Leafmite