What happened with this Angraecum

[BrassavolaStars]

Hello all,

I am at loss.

As you can see from the photos, this Angraecum is in very bad condition. It only took a week for it to get some damage to this point. What happened? It has been a bit cold in the greenhouse (49f) and dry (30% rh) for a few weeks. The spots are not mushy but flat and dry like something sucked all the moisture out.

I am concerned it could be something more serious than a cultural problem. Can anyone tell what happened?

[estación seca]

My first 10 guesses would be sunburn. Did you have a string of sunny days?

My next guess would be a tiny opening in the greenhouse directly over the plant so freezing air descends down onto it. If you have good air circulation near this plant (fans) that is not likely.

[BrassavolaStars]

Originally Posted by estación seca

My first 10 guesses would be sunburn. Did you have a string of sunny days?

My next guess would be a tiny opening in the greenhouse directly over the plant so freezing air descends down onto it. If you have good air circulation near this plant (fans) that is not likely.

It does look like sunburn but it has been snowing and overcast a lot and a lot of this damage happened during this time. I also have a pretty strong shade cloth. It was near to the heater but not near any doors or vents.

I almost want to say cold damage, but then again, nothing else (even phals and more tropical vandas) seem to show much stress. The only plants that are having issues are the angraecums, cyrtorchis, and aerangis.

I had another angraecum just turn completely black and another turn shrivel and turn rusty. I am wondering if it could be drought conditions? My heater has been acting up lately and making it too warm/cold but also dry. I have been watering once a week as I do in the winter and I am having a lot of wrinkled leaves and bulbs on the vandaceous and cattleya types.

[aliceinwl]

I saw similar damage to some Phalaenopsis that I tried to grow outdoors year round. I attributed to some type of rapidly progressive bacterial or fungal infection taking advantage of a cold stressed plant. It tended to happen when both day and nighttime temperatures stayed cool for an extended period in late winter or early spring: I think the affected plants just hit their limits.

[BrassavolaStars]

Originally Posted by aliceinwl

I saw similar damage to some Phalaenopsis that I tried to grow outdoors year round. I attributed to some type of rapidly progressive bacterial or fungal infection taking advantage of a cold stressed plant. It tended to happen when both day and nighttime temperatures stayed cool for an extended period in late winter or early spring: I think the affected plants just hit their limits.

Time to break out the copper/physan?

[Leafmite]

Wow. My guess would be sun or cold damage but I really don't know what your conditions are or what temperature/light range your Angraecum needs. I always baby my Magdalenae as it is one of my favorite orchids so this is rather horrifying to see. I hope you find the solution and are able to save it.

[Keysguy]

Looks like cold damage to me. 49 is awfully cold for an Angraecum, especially if it's exposed to that for any length of time. Probably would have happened even faster if it hadn't been dry.

[Roberta]

My Angraecums (including A. sesquipedale) tolerate colder than 49... I only have a few little ones in the GH. (Buds not so much, but leaves are fine) That looks a lot like REALLY cold damage... could it have been hit by a direct blast from an open vent? Or a blast of heat from the heater where that particular one just happened to be in the way?

[BrassavolaStars]

The general consensus seems to be temperature or sun damage. While that is unfortunate, at least I do not have to be concerned about it getting worse or be concerned about a nasty fungus that could spread to other plants.

---------- Post added at 10:30 PM ---------- Previous post was at 10:28 PM ----------

Originally Posted by Roberta

My Angraecums (including A. sesquipedale) tolerate colder than 49... I only have a few little ones in the GH. (Buds not so much, but leaves are fine) That looks a lot like REALLY cold damage... could it have been hit by a direct blast from an open vent? Or a blast of heat from the heater where that particular one just happened to be in the way?

The blast from the heater is what I am thinking happened. It has malfunctioned a couple of times this season and made temps close to 95f inside. Not only did this dry out my plants but it also incurred a multi-thousand dollar energy charge for that month . This plant was in fact in the path of the heater.

My thermometer says that the coldest it got in the greenhouse has been 50f where this particular plant was. That said, I have another temperature gauge in the colder section of the greenhouse that allegedly got down to 41f in some sections. I think I damaged some phals and others that way.

[Roberta]

Originally Posted by BrassavolaStars

The blast from the heater is what I am thinking happened. It has malfunctioned a couple of times this season and made temps close to 95f inside. Not only did this dry out my plants but it also incurred a multi-thousand dollar energy charge for that month . This plant was in fact in the path of the heater.

My thermometer says that the coldest it got in the greenhouse has been 50f where this particular plant was. That said, I have another temperature gauge in the colder section of the greenhouse that allegedly got down to 41f in some sections. I think I damaged some phals and others that way.

Yikes! Both the damage to plants and the energy bill! Yes, I think that's heat damage on the Angraecum... if the ambient temperature was 95 deg F, the heater was putting out much more, and the plant that was unlucky enough to be in the path of the output got toasted! My condolences!

You could trim the totally fried leaves, but my inclination would be to just let them fall naturally (which they will) if you can tolerate the pain of looking at them. Then you won't end up cutting away something that might still have life in it (and so benefit the plant) even though it looks bad. Not a disease, so any spread that you see is just damage that takes awhile to show. The plant very likely will survive, even if it looks ugly for a few years until it grows some new leaves.