Probable rot on Angraecum

[BrassavolaStars]

Hello all,

It has been a bit because I haven’t had many problems. Unfortunately today, I seem to have what looks like an orchid emergency.

I got this Angraecum eburneum about a month ago. When I received it, one of the leaves was drying out at the base. In spite of this the orchid bloomed off of two healthy spikes and for that time I kept it in my house (instead of the GH).

By chance, after the blooming was done and the spike started to turn brown, I accidentally knocked off the leaf with the dried base and found a fair about of dark patches at the base of the plant.

This is very much worrying me as it reminds me of crown rot. Is this normal? Are these just older leaves that are going to fall away, or do I have a serious infection on my hands. I am thinking it is the latter as these spots, while not mushy, do not smell very good.

What should I do? Cinnamon? Hydrogen peroxide? Physan? Should I remove the bad tissue? Should I leave it alone? Is it serious enough to perform a surgery? Could a rotting spike have caused this? I never let water get in between the leaves.

[WaterWitchin]

Looks like crown rot to me. I'd get that yellow leaf with the black at bottom cut away as best you can, and put cinnamon on with a Qtip, on all black spots. Then use a systemic fungicide on it. Wait for some advice on fungicide. It's not an area I know much about.

[BrassavolaStars]

Update. I cut away the problematic leaf only to find more area of issue. It doesn’t seem like i can cut this away though as it is fused to the plant itself like part of the stem.

Here are the photos.

What should I do next? I am starting to think the worst. Hopefully I didn’t cut into anything too deep. Looking at the photos, it really does look like the spike rotted and then infected the stem.

[Roberta]

Originally Posted by BrassavolaStars

. Looking at the photos, it really does look like the spike rotted and then infected the stem.

Might have been the other way around... that the stem had hidden rot that caused the spike to rot. You're right not to keep cutting - which can cause more damage. Looking for advice from others who have more experience with fungicides and rot issues than I do. (Growing outside in a semi-desert has its advantages)

[SouthPark]

Originally Posted by BrassavolaStars

What should I do next? I am starting to think the worst.

I think it might be something like erwinia - bacteria, or even fungal activity. One approach to handle this is to break out a hopefully workable treatment (such as agri-fos systematic), and also pot the orchid into an airy media (if not already) - into a good drainage pot. And provide gentle air-movement (not necessarily constant - but at adequate amounts of air-movement) to leaves, stem, media and roots. A pot with good size drainage holes helps with the air-flow through the pot.

It'll probably be a good idea to unpot your orchid to see if any particular region within the media is creating super wet regions of stationary (unmoving) water - which can be avoided with airy-enough media, and good air-flow through the pot and media.

If you apply a treatment (such as agri-fos, or in my region yates anti-rot phosacid), it could just stop the issue in its tracks, where the marks will stay there, and dry up, and the orchid has no problem after that.

[WaterWitchin]

I’m thinking apply the fungicide, however one applies it, and not repot yet unless it’s sitting in really bad media. Too much trauma to repot at same time. Let it get some systemic action going on first, and watch. When/if it appears the rot isn’t spreading, then repot. That’s my two cents.

[BrassavolaStars]

Hi all,

Fortunately, it is already in a good potting medium. It is currently potted in coarse bark which doesn’t stay wet and is not really degraded much at all. Here is what I have at my disposal in terms of disease control/bactericide/fungicide: Cleary’s, Captan, Copper, Physan, Aliette, Hydrogen peroxide. Which is best and how should I apply it?

[SouthPark]

I'd break out the Aliette to start with. Mix to the recommended proportions with water, and spray all the leaves and the stem. And provide decent air-movement.

Was this plant previously getting good air-movement for the leaves, stem, roots, and media? Pot is good drainage? Just double-checking.

[BrassavolaStars]

I had this plant near an open window and it is fairly windy where I live so I think it was getting fairly good air circulation. There was enough of a breeze to have the smaller plants near it sway very slightly.

I will admit though when it was indoors for display instead of in the greenhouse, it probably wasn’t getting as much circulation as in the greenhouse.

I am assuming the pot was well draining enough as within a week of watering, the media would be thoroughly dry. I also forgot that I have daconil and immunox but I will start with the aliette.

[SouthPark]

Sounds like good growing conditions. Indoors for display is quite ok. When indoors - no problem, as long as it's not still-air for relatively long periods of time.