Oncidium gold dust with whitish patches on pseudo bulbs

[sweta]

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.