yellowish/tan splotches on Oncidium leaves

[Sahlabiya]

Thanks,

I'm attaching two more photos that are clearer - they show the parts that I originally cut off (there have been no more like the brown tip - I suspected it might be salt toxicity so I flushed it well with distilled water at the time).

Yesterday I cut off all of the parts that looked brownish tan and sprayed the whole plant with fungicide. The dark spots seem to be going deeper into the plant on several leaves now and I noticed that the tips of two aerial roots are tannish-brown. I'm wondering if there is left over fungus from before, and hoping that if so, I can get rid of it...