Blc. with black spots/yellow leaves

[etcherkate]

I don’t like the looks of this at all! Some time in the last week, my Blc. has developed sunken black lesions on a new growth. The rest of the plant looks fine, and none of my other orchids have the same symptoms.

I moved my 40 or so orchids out of the window sills and under lights a few months ago, along with some herb seedlings. The orchids have never been happier: all of the phals are in spike, as are a couple of Oncidiums. The only problem I’ve had is aphids on my basil and fennel. The affected plants have been moved to another area of the house while I pick the aphids off one by one. Aside from occasional gnats, I don’t see any bugs on the orchids.

My inclination is to cut the affected area of the Blc. off with a new razor and move it to another area of the house, where it won’t be happy with the lighting, but I won’t risk spreading the problem to other plants.

What do you think? Bacterial infection? Fungus? Thank you in advance for your help!

[estación seca]

What is the ambient temperature? That kind of shoot loss happens with insufficient watering and with too-cool temperatures. The green leaf I see is wrinkled, suggesting the plant didn't get enough water at some time in the past.

It is hard to get good healthy growth on Cattleyas in a temperate winter, even with supplemental lighting. Most people's growing areas are too cool for strong growths.

[etcherkate]

Originally Posted by estación seca

What is the ambient temperature? That kind of shoot loss happens with insufficient watering and with too-cool temperatures. The green leaf I see is wrinkled, suggesting the plant didn't get enough water at some time in the past.

It is hard to get good healthy growth on Cattleyas in a temperate winter, even with supplemental lighting. Most people's growing areas are too cool for strong growths.

This time of year, the temperature is about 60 degrees overnight, and 65-70 during the day, depending on whether anyone’s home. I wonder if the leaves are wrinkled because I waited too long to repot? I also suspect that I burned some of the new root tips with fertilizer; I’m now mixing my solution at a quarter of what the manufacturer recommends.

I have an older book on orchids that dates back to when Cattleyas were the most popular orchids grown by hobbyists, a fact that I find baffling. Cattleyas don’t seem to like my conditions at all!

[Roberta]

Originally Posted by etcherkate

This time of year, the temperature is about 60 degrees overnight, and 65-70 during the day, depending on whether anyone’s home. I wonder if the leaves are wrinkled because I waited too long to repot? I also suspect that I burned some of the new root tips with fertilizer; I’m now mixing my solution at a quarter of what the manufacturer recommends.

I have an older book on orchids that dates back to when Cattleyas were the most popular orchids grown by hobbyists, a fact that I find baffling. Cattleyas don’t seem to like my conditions at all!

There are Catts and then there are Catts... so much variation in parentage, with some being far more forgiving than others. It's really important to know something about your specific plant, to determine the conditions that it actually wants. They do tend to be rather strong epiphytes - use large bark, let them dry between waterings and repeat. When repotting, it is critical to do it when new roots are just starting. That can be at any time in the new-growth or bloom cycle, depending again on parentage. (New growth and/or blooms are irrelevant, it's all about roots) Some root only once a year, others may do it more often. You just have to watch..once one or two new ones just emerge, do the potting, make sure that the plant is very stable in the pot. Then when more new roots emerge, they will establish and grow. But those new little root tips are so easy to damage, you need to pot when the plant is actively creating them - if you do it when it is just starting, those first couple might get damaged, but there will be more emerging shortly.

[estación seca]

Catts survive temperatures like yours but aren't happy. The leaves are wrinkled because they didn't get enough water. This could be from sick roots or from insufficient watering. What I can see of the roots look good, so I suspect you haven't been watering enough. I think the damaged new shoot is from insufficient water combined with cool temperatures.

[Roberta]

Originally Posted by estación seca

Catts survive temperatures like yours but aren't happy.

I beg to differ on temperature - depending on which Catt. I grow a LOT of Cattleya species and hybrids outside, which in my climate means that for several months, night temperatures are in the low 50's down to the 40's and lower (Fahrenheit) and they grow and bloom very nicely. I do water less, but that is just because with lower temps and low light angle, things don't dry out as fast. There are a few species and hybrids of those that do need winter protection... greenhouse goes down to 60 deg F but not much lower. 60 deg. F should not be a challenge for any but a few really picky species and their immediate hybrids. And Catts are more forgiving of low humidity than many other types, since they need to dry out anyway. Light is a biggie, but even there, lots of people on this forum grow Catts on widow sills and such, at northern latitudes where light is quite poor and get away with it.

[etcherkate]

Originally Posted by estación seca

Catts survive temperatures like yours but aren't happy. The leaves are wrinkled because they didn't get enough water. This could be from sick roots or from insufficient watering. What I can see of the roots look good, so I suspect you haven't been watering enough. I think the damaged new shoot is from insufficient water combined with cool temperatures.

It sounds like this is a problem related to my growing conditions, and not something horrible like a virus that will race through my collection and destroy it?

Maybe I could try to come up with a solution for raising the temperature in the immediate vicinity of the orchids. I hate to crank the heat in the winter when no one’s home, but I’m also a little creeped out by the thought of running a space heater unattended.

[Roberta]

Originally Posted by etcherkate

It sounds like this is a problem related to my growing conditions, and not something horrible like a virus that will race through my collection and destroy it?

Maybe I could try to come up with a solution for raising the temperature in the immediate vicinity of the orchids. I hate to crank the heat in the winter when no one’s home, but I’m also a little creeped out by the thought of running a space heater unattended.

Out of curiosity, does your Catt have an ID tag? That would help diagnose whether temps are adequate or not (I really do doubt that your range is all that problematical, I would look more at media and watering)

[etcherkate]

Originally Posted by Roberta

Out of curiosity, does your Catt have an ID tag? That would help diagnose whether temps are adequate or not (I really do doubt that your range is all that problematical, I would look more at media and watering)

It does—the tag says (Blc. Waianae Leopard x Ctna. Why Not) ‘Orange.’ No idea who the grower or vendor was. It was in bloom and apparently healthy when I bought it, but I suspect I waited too long to repot.

[Roberta]

Originally Posted by etcherkate

It does—the tag says (Blc. Waianae Leopard x Ctna. Why Not) ‘Orange.’ No idea who the grower or vendor was. It was in bloom and apparently healthy when I bought it, but I suspect I waited too long to repot.

Both of those hybrids are quite cold-tolerant, so I really don't think temperatures are a problem (Ctna. Why Not is blooming as I write, has been going for several weeks, and while I don't have Blc Wainae Leopard, I know others who have grow it outside in my area) If you suspect bad media, you're probably right. Don't worry about the new growths that have failed... once conditions improve, it will very likely pop out some new ones successfully. Watch for signs of rooting (new growth may be an indicator and it may not) and as soon as you see that happening, drop whatever else you may be doing and repot. (C. gutttata, which is half of Wainae Leopard, is rooting now on my two plants, which do fine outside with the low temperatures. So keep an eye on it)