White mold on Oncidium Nanboh Waltz pine bark

[Wilder]

Hello,

I got an Oncidium Nanboh Waltz Boso Sweet yesterday. The plant looked very healthy at the store- succulent pseudobulbs, good roots visible through the pot, and largely unblemished, shiny leaves.

Last evening after I got it home, I noticed that the pot seemed slightly overpotted with pine bark and the pseudobulbs were a little buried. I started removing a layer of bark, only to notice white mold growing on the lower layers of bark.

I got in touch with the store I brought it from immediately after. They took a look at the photos, and told me that white mold on the bark is nothing to worry about and that a thorough drying up of the medium will help. Today, the mold seems to have covered more bark chips and the pot smells mildly like fresh mushrooms. There's also tiny, cream coloured spheres all over the base of the pseudobulbs on the bark that may be spores (?).

The good news is that the plant (leaves, pseudobulbs and visible portions of roots still look very healthy, for now.

What should I do from here on? Will the mould die? Should I treat the roots and medium in something? The links in the sticky on this forum don't mention anything in particular to white mold, just black mold. I'd appreciate any insight anybody has to offer, please!

[aliceinwl]

The breakdown (fungus) on the media is an indication that the media is old. The best thing to do at this point is to repot your orchid into fresh media. Repotting is time consuming so a lot of in-store orchids are overdue for a repot. Throwing an orchid (old media and all) into a larger pot, packing it with more media, and drenching it with water is standard practice: they are concerned about the plant surviving through its current bloom without any additional in-store care. After its done flowering the customer can throw it out and buy a new one.

The fungus on the bark is unlikely to hurt your orchid, but as the bark continues to break down the media will become more soil like. This will ultimately result in the air spaces filling in and the roots being smothered. Don’t try to treat the roots and media. Home remedies like hydrogen peroxide will just damage the root tissue.

If this is a plant that you want to keep long term, I’d repot it as soon as possible (don’t wait for flowering to finish) so you can prevent any root death.

[Wilder]

Originally Posted by aliceinwl

The breakdown (fungus) on the media is an indication that the media is old. The best thing to do at this point is to repot your orchid into fresh media. Repotting is time consuming so a lot of in-store orchids are overdue for a repot. Throwing an orchid (old media and all) into a larger pot, packing it with more media, and drenching it with water is standard practice: they are concerned about the plant surviving through its current bloom without any additional in-store care. After its done flowering the customer can throw it out and buy a new one.

The fungus on the bark is unlikely to hurt your orchid, but as the bark continues to break down the media will become more soil like. This will ultimately result in the air spaces filling in and the roots being smothered. Don’t try to treat the roots and media. Home remedies like hydrogen peroxide will just damage the root tissue.

If this is a plant that you want to keep long term, I’d repot it as soon as possible (don’t wait for flowering to finish) so you can prevent any root death.

Thank you, this puts me at ease! I do want to keep the orchid for as long as possible. Pine bark is currently unavailable where I am at the moment, but I will repot it as soon as I can.