Oncidium gold dust with whitish patches on pseudo bulbs
 

Hi all,

The Oncidium gold dust orchid that I ordered about 2-3 months ago has developed whitish patches on the pseudo bulbs. In fact this started on one of the noid oncidiums in my collection. I treated them with horticultural oil, soap water, alcohol but nothing seemed to help so I cut out the part of the pseudo bulb with the white patches but that didnt stop it from spreading to other oncidiums that were closeby and gold dust one was also one.of those. Could this be some kind of scale or could it be fungal infection? I'm attaching pictures will appreciate thoughts and ideas as to what this could be. Its grown in orchiata bark and sphag moss, watered once a week(will increase the frequency shortly) with home temperatures 70F and low humidity.

It's hard to say; I can't see the photos well. It would be good to see a better photo of the brownish patch on the pseudobulb at the right side of the third photo.

The patches might have been mechanical damage from being scraped. I don't cut off damaged patches, especially from such small plants.

The bark is much larger than I would use for a small Oncidium. Like the Twinkle, this should not dry out.

The brownish patch is actually cinnamon powder that I applied after scrapping off the whitish patch. I've been so paranoid lately about passing on pests or diseases to other plants. I dont want to be hard on these tiny plants and use extreme measures but also want to keep them pest free. Should I quarantine this plant? I think I used fine bark similar to twinkle with gold dust ot maybe I ran out of fine bark at some point. Yes will water these more.often as suggested.

Any chance there’s a slug/snail/etc hanging about? It wouldn’t explain the white haze on the leaf but could be the cause of the lower damage.

Hmm I dont think I've ever seen snails or slugs come with any of the orchids. Also I usually repot any new plant before introducing it to my collection. I use mild dose of hydrogen peroxide on roots when repotting to kill any snail or slug eggs so the chances are very very low.

Hydrogen peroxide won't kill snail nor slug eggs, but it can damage orchid roots. Bush snails may infest potting media. They are tiny at maturity, the size of a pencil point, and very easy to overlook.

Hmm....peroxide I use it normally on mature plants only and not on tiny ones also make it a point to rinse the roots with water after couple of min. So far never hsd issues but will keep this in mind. Wow never knew bush snails can be so tiny will need to watch out for them.

You do you, but check out this recent discussion about H2O2.

Hydrogen Peroxide - Toxic to Orchid Roots