Brown patches under leaves: Phal. amabilis sick?

[Sharon's Sheepdogs]

I think adding the spag was a good idea. Just keep it out from under the crown of the phal so crown rot doesn't develop. What you might want to do for now is put a couple teaspoons of physan 20 in a gallon of distilled water, pour some in a plastic bag & gently drench the entire orchid, bark & all in the water for 5 min. & then allow the phal to hang upside drown. This will allowi the water to completely drain out of the crown, I would do this every few days allowing it to almost dry before repeating. I always add a teaspoon of physan to the water I am using to water my orchids as a preventative.Hopefully this will help the orchid until what is really wrong can be determined.

If there is any possibility this is crown rot though, I would recommend a completely different approach.

The phal had previously been growing outdoors. In what conditions is it growing now? Trying to determine if it is a bacterial disease (since there's browning on the leaves) or if it's having difficulty acclimating to its new conditions.

[rbarata]

I think adding the spag was a good idea.

Given the dry look of the roots without almost no media to hold moisture, I agree.

About the original question (the spots), sorry but I can't help.

[jkofferdahl]

The roots do look dry, and I don't see any fresh growth tips on them. I have to ask about the humidity where they plant grows - do you know the level?

I'd not rule out either a fungal or an insectal infection at this point. You should look into that. Some insects are tiny enough to be hard to see. However, I'm still leaning toward watering and humidity. The condition of the roots, which should be chock full of new growth at this time of year, concerns me; they're goor, and will support the plant, but should be doing better. Also, the undersides of the leaves of the plants appear to have a bit of folding/wrinkling to them which is also indicative of being underwatered. I'd possibly put a small amount of sphagnum back, but I would also really urge you to try watering twice a day. A mounted Phal can't really be overwatered, but it can easily be underwatered!

[bil]

My thoughts are that watering is best done in the morning with water at the ambient temp.

If it had crown rot, my advice would be to bin it, but I don't see that.

My first treatment would be a fungicide and an anti bacterial too to be on the safe side.
The roots look fine and shouldn't be physically able to get too wet. My mounted phals have a good big pad of moss over the roots, and they get sprayed every day when it's dry, and every 2-3 days when it isn't. Watering with a spoon is tedious and time consuming, IMO.

Crown rot in phals is I feel exclusively caused by heat or cold. I have never got it from wetting the crown. Other orchids you should always do your best to avoid wetting the leaves and crown, but phals just don't care.

[Roberta]

looking closely at the underside of the leaf, I wonder if there might be spider mites. (They are very tiny. They "stipple" the underside of the leaf so it ends up looking silvery). If that's the pest, insecticides wont kill them (they're arachnids) Soapy water or an oil-based product will kill them though. If they went from a humid area (outside) to a less humid one (the inside of the house) they could multiply (especially if air movement isn't great) The roots look good. Don't look dehydrated to me

[bil]

If it is spider mites, you can always buy an acaricide.

[jkofferdahl]

A good dusting of DE will also take care of them.

[Dragonar]

Hi guys,

Thanks so much for the replies!

Yea the pictures that I uploaded were after I removed the initial sphagnum so that we can have better assessment of the roots.
Previously the sphag were just covering the mount but not the roots (in an attempt to better aerate the roots) but currently I have added more sphagnum to cover all the roots if possible.

Doesn't seem to be a case of crown rot though as a new leaf developed but it definitely is growing slow. Humidity is 75% right now according to google.

Previously at outdoors, it had just very little sphag and rain fall lasts for 2-4 hours each time. There will be days where there is no rainfall or twice the amount of rainfall though.
Currently, it is by my NE facing window and I've added sphag to it.

I did see one spider mite (or something that looks like it) the other day crawling on my hands when I was watering this orchid. Never saw anymore of them ever since. There are no webs as well. Problems with getting orchids that were grown outdoors :/

Previously I had an infestation of mealy bugs on two of my potted orchids that were grown outdoors previously, from the same source I had purchased my amabilis. Noticed the infestation in a week or two after purchase (I always repot my orchids straight) and sprayed lemongrass oil on the roots, left it there for a few days and flushed the oil out during watering. It did work wonders but after that, almost all of the roots shriveled and it did take sometime for both of them to recover. Not sure if I am using it in the correct method?

I will try and purchase physan 20 or something similar

[Roberta]

I don't think you want to put oil on the roots - you saw that it damaged them. On the leaves, where the bugs live, is the place to do it - cover the leaves well (especially the bottom), get it down into the crevices at the base of the leaves.if you saw one spider mite, there are others. They don't show webs until you have a REALLY serious infestation. But they are very small... unless your eyes are much better than mine, a hand lens is very useful to look for them. Growing outside, with the rain and wind, they may be around but they stay under control. Inside the house, they may multiply. Soapy water drowns them, oil smothers them. Be sure to treat again after about a week - no treatment kills the eggs, and may not kill the larvae. So you need to repeat the treatment several times to get all the generations.

Physan is an algicide and fungicide, but won't do anything to the bugs. It may slow down rot if it gets started. Powdered cinnamon (from the kitchen) is a good fungicide - if you cut away a rotted section of leaf, dust the cut with cinnamon.

[Dragonar]

Well, I placed it on the roots as that was where the mealy bug were previously. Nothing much on the leaves if I could recall. But yes I agree that if there's one there will be others. Shall do something to it now as a preventive