What's happened to my Den Phal?

[mexicowpants]

Walking past my Den Phals this morning, I happened to notice this:


What is it? It had a pretty fast onset, just a couple of days ago it was fine. Now whatever this is is affecting one of this year's new growths and one of last year's.
I did kind of forget to water itthis past week (we've had a dry spell in the middle of our rainy season, so humidity had decreased somewhat), but I can't see how a few dry days would cause that.
The crowns haven't gotten wet, there's been good air circulation, no new plants have been introduced to their growing area... Basically business as normal.
It hasn't gotten any worse since this morning, but it's definitely got me concerned. What is it, and how should I proceed? I REALLY don't want to lose this one!

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[estación seca]

I don't have any idea, but I would cut off that pseudobulb at least 5cm / 2 inches below the sickly parts. And coat the cut with cinnamon.

[dounoharm]

I will stick my neck out once more....I believe it looks bacterial...in the summertime, I like to spray a bit more with physan, and pay attention to any cut or divisions with a physan bath, weak but ensure all parts get a wash....and provide plenty of ventilation...keep those fans blowing!

another thing...in the summer we travel more, and the house orchids and the greenhouse don't get watered sometimes for two weeks! so far, knock on wood, they have been fine with this....the gh has a aquafog 700 that mists frequently, but the light stand just has their gravel....

[bil]

Where the leaf joins the stem in one pic are the sort of white blobs that have me reaching or the pesticide.

[silken]

Originally Posted by bil

Where the leaf joins the stem in one pic are the sort of white blobs that have me reaching or the pesticide.

Good eye. I see a bit of white too, in the third picture. Could it be immature scale down in there???

[mexicowpants]

Originally Posted by silken

Good eye. I see a bit of white too, in the third picture. Could it be immature scale down in there???

Nope, thoroughly checked, and no bugs. Recently had a scale problem on my outdoor plants, but this is an indoor one totally isolated from the others. I reckon what you see there is dust - it's high time I gave the leaves a wash down.

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[mexicowpants]

Originally Posted by dounoharm

I will stick my neck out once more....I believe it looks bacterial...in the summertime, I like to spray a bit more with physan, and pay attention to any cut or divisions with a physan bath, weak but ensure all parts get a wash....and provide plenty of ventilation...keep those fans blowing!

It looks as if the leaf on the older growth (pics 2 and 3) was just reaching the end of its life... The leaf has come off now and the rest of the pb looks fine. I'll keep it under close inspection for the next few weeks. I can't understand how it could be bacterial, though - the plants and the surrounding air have both been much drier recently, and there's always good air circulation in this area of my house. And the plants have been isolated and pretty much untouched in this area, so no chance of cross-infection. Weird.
Nevertheless, I'd like to give them a precautionary spray with Physan, but I can't seem to find it here - is there any kind of alternative I could use?

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[mexicowpants]

Originally Posted by estación seca

I don't have any idea, but I would cut off that pseudobulb at least 5cm / 2 inches below the sickly parts. And coat the cut with cinnamon.

The good news is that it hasn't spread (most of the affected leaves pulled off quite easily today, and looked dry - no sign of rot - and the crown looks healthy. No other leaves are affected). May wait another couple of days before deciding whether to amputate... Thoughts?

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[estación seca]

My Den phal leaves are well on the way to dry brown paper before they fall off, and they're never green at the base. Your leaves might be falling off prematurely because they're sick and the plant wants to get rid of them.

[mexicowpants]

Originally Posted by estación seca

My Den phal leaves are well on the way to dry brown paper before they fall off, and they're never green at the base. Your leaves might be falling off prematurely because they're sick and the plant wants to get rid of them.

...so would you still recommend amputation?

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