Cattleya dowiana new growth turning black?

[katrina]

Originally Posted by Leafmite

Katrina, I am sorry to hear that you have lost a few. Ohio weather is just so unpredictable. I know a few people in our OS have been having problems, too, with their orchids rotting away and some others just gave up and brought them all inside. I think that I must be lucky, then, or the fates are showing mercy after my attempt at growing under lights.

Yep, it's definitely been a challenging summer in central Ohio but compared to some in my OS...I've been very lucky. I know people who have lost a lot more. A LOT.

As for bringing them in...nope, not doing it until I have to. Which, might not be much longer if these temps keep going down. Every year seems to carry w/it one challenge or another and I think it's just part of growing out in the elements vs the control environment they have in the winter. I look at it as Mother Nature helping me free up space for new orchids. I just wish she'd ask me if there are any that she should not touch.

Some losses hurt more than others and a newer Cattleya violacea Rubra that I got from Ecuagenera earlier this year ranks right there. sniff, sniff. That vio and a nice walkeriana coerulea will be the summer of 2015 losses that hurt the most.

Originally Posted by ramonypony

I had to cut down a lot further than I thought I would have to to reach green tissue, down to the base. In the pic you can see the first cut I made which was quite nasty. Hopefully it was enough to stop it.
I repotted it into a wooden basket with lava rock and separated it from the others.

Good thing you cut to the green but keep an eye on it because you might not be out of the woods just yet. And, since dowiana is not real fond of being messed with, you might find just leaving her in an pot w/no media might be best until you're sure you don't have to do anymore cutting. Just a thought.

[Ray]

Physan is topical only. A systemic fungicide is a better bet.

I can suggest two potential approaches, and the selection should be based upon the degree of infection, and your own attitudes:

Daily, thorough, sprayings with Inocucor Garden Solution at 3 - 4 tablespoons per gallon, for about a week. I have used that to cure erwinia, and it has a residual effect of preventing rots.

The other is application of a systemic chemical fungicide. The most-often brand name is Clearys 3336, but that is petty pricey, and usually only available in larger sizes than what we need, but I've managed to find a generic equivalent - Thiomyl - that's a lot cheaper in both 2- & 6-ounce jars.

[Leafmite]

It is probably best not to mess with the roots too much at this time of year. Many say that this is a difficult one because it is fussy but if you are careful, it should be fine. I was accidentally sent a dowiana seedling instead of another Cattleya I had ordered and it was in fine bark, in a pot. I wanted to send it back but they told me to keep it. In my cooler home, the roots were doomed in that set up. Yet, I knew that this one is fussy about being re-potted at the wrong time of year. I decided to leave the roots mostly exposed and put it in a Vanda basket with a few lava rocks to weigh it down (if you have a larger one, you can stake it to hold it in place). The roots, surprisingly, kept growing all winter. I kept it for the year and then found a new home for it in the autumn, when it was established.

[isurus79]

Originally Posted by ramonypony

But I guess the air is still more humid than this dowiana likes it, none of my other orchids have had anything like this.

Dowiana LOVES humidity! Its just that the roots need to dry fairly quickly between watering. These guys naturally live at the tops of tall trees in the rainforest, so they get a ton of rain, but they dry quickly. This species is VERY sensitive to this in winter. You still have some time with this growing season and your plant might still throw another growth.

Originally Posted by ramonypony

I repotted it into a wooden basket with lava rock and separated it from the others.

Sounds like a good plan. Next summer, you might need to water this one more frequently than this summer, but with good air movement around the plant, it will dry quickly.

---------- Post added at 08:02 PM ---------- Previous post was at 08:01 PM ----------

Originally Posted by Ray

Physan is topical only. A systemic fungicide is a better bet.

I can suggest two potential approaches, and the selection should be based upon the degree of infection, and your own attitudes:

Daily, thorough, sprayings with Inocucor Garden Solution at 3 - 4 tablespoons per gallon, for about a week. I have used that to cure erwinia, and it has a residual effect of preventing rots.

The other is application of a systemic chemical fungicide. The most-often brand name is Clearys 3336, but that is petty pricey, and usually only available in larger sizes than what we need, but I've managed to find a generic equivalent - Thiomyl - that's a lot cheaper in both 2- & 6-ounce jars.

Good to know! Thanks!

[Leafmite]

Originally Posted by katrina

Yep, it's definitely been a challenging summer in central Ohio but compared to some in my OS...I've been very lucky. I know people who have lost a lot more. A LOT.

Some losses hurt more than others and a newer Cattleya violacea Rubra that I got from Ecuagenera earlier this year ranks right there. sniff, sniff. That vio and a nice walkeriana coerulea will be the summer of 2015 losses that hurt the most.

Those are really tough losses as they are beautiful orchids. I am not sure how disappointed I would be if I lost my $8.00 walkeriana (you know if it was that cheap, it isn't going to be winning prizes).

If it is any consolation, you are not the only one, it seems to have had trouble with the violacea. Even the Bakers had a bit of trouble!

Warm-Growing Cattleya Culture

After reading it, I am going to get that luteola inside.