brown spots on Laelia rubescens pseudoulbs???

[mollyminiveg]

Hi,
I am new to orchid growing and within the last two weeks, 2 out of 3 of my Laelia rubescence alba pseudobulbs have been turning brown or have brown spots, and wrinkling. The third one is green and big and has just flowered. The climate is dry where I live so I have the orchid on a humidity tray and was using a humidifier for a while next to it. It gets direct sun for 3 hours in the afternoon when it's not cloudy. There are no bugs. Are these pseudobulbs dying? I water every other day or every third day and mist once a day. Your sugestions would be very helpful. Thanks





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[D&S Mabel]

Can you try reposting your photos as I am not able to get them to enlarge (when I click on them, I get an error that they are not in the database). This would help in being able to see the spots you are referring to and maybe telling if they are something to worry about or not.

I have a couple of these plants that are mounted on tree fern slabs and grow year round outside. They have no other growing media (no sphagnum moss, etc. added to the mounts). At this time of year, they get about 2-3 hours of direct morning sun with bright shade the rest of the day, are watered once a week and are allowed to dry out between waterings. All are currently in bloom with multiple spikes as below -



Some of my p-bulbs have brown or black patches on them but these don't seem to effect the plant at all. I see them most on older bulbs which also wrinkle as they give norishment to the rest of the plant and slowly die off.

I realize that your growing conditions are alot different then mine but I would suspect that you may be watering yours too often, especially since it has finished blooming and is probably not actively growing. Keeping them too wet can lead to roots dying off and the plant declining. Check your roots to see what is happening there. Are they healthy?

You might also consider mounting your plant as I have been told that they do best grown this way.

[mollyminiveg]

Thanks for your response. Yours is beautiful! I suppose I am watering too much. The roots look OK, but are still wet from yesterday morning's watering. Do you think I should still mist the plant or cut back on that too? I'll look into mounting them as I've never done that before. I still can't seem to figure out how to post an expanding thumbnail photo, so here are some giant pics. Thanks again.

[dounoharm]

they look fine to me, just normal wear and tear maybe, and it sounds like they need to dry out more between waterings....

[mollyminiveg]

Thanks, I feel much better about their future, and will cut back on the water.

[Ross]

It looks like the mix is exhausted to me. If this were my plant I would have repotted to fresh mix long ago. Moss on top in your climate means the mix is pretty wet underneath. As Ray has pointed out in the past, this means the air spaces are full of detritus and water and the roots cannot get the oxygen they need. I'd bet if you knock this plant out of its pot, most of the roots will be brown and mushy (rot). The brown on the pseudobulbs might be related to this.

If you opt for repotting, try and find some Thiomyl powder. Mix up a batch and soak the whole plant (bare root) after trimming off all the brown mush. Then let dry out overnight. There should be white blotches all over the leaves and pseudobulbs. That's the chemical residue. Leave it there. Prop the plant on top of the new mix (or if you have found viable roots, then get those down into the new mix. You might have to tie the plant into the pot to keep it from wriggling around. Wait till new growths appear before watering heavily. In meanwhile, just spray the top of the mix and the leaves with pure water (distilled or RO) daily to keep the whole plant from shrivelling. If it does start to shrivel, place it in a plastic bag out of direct sun (to raise the humidity) but be watchful for mold. Hope this helps. The Cat alliance only roots from new growths. Rarely, some of the old back-bulb roots may spring out with side roots. This means culture is optimum.

[D&S Mabel]

Yes, looks like normal wear and tear on the bulbs to me too. I don't think you have anything to worry about there.

As Ross points out, your potting material is on its last legs and, although there are a couple green roots showing, their tips don't look that great. I too suspect that if you unpotted this plant, you would find that the roots are not in the best of shape.

I think you either need to repot or mount it soon.

[mollyminiveg]

Thank you all for your advice! I will plan on repoting, or mounting soon. I will also find some Thiomyl powder to use.