Yellow spots, lesions, bumps on phalaenopsis--pests or edema or something else?

[Shauna]

Hello! I am new to orchids and am noticing some problems in two phalaenopsis I've had for a few months. They have been going along fine, with one producing a new leaf, and the other trying to make new buds and branches on an existing spike. Recently though, I noticed a huge (1" or so) grayish lesion on the underside of one of the leaves. Shortly after, I started noticing pale yellow-green spots on the top side of the leaves that are especially visible when held to the light. When I examine the underside of the leaves, the spots appear dark green and slightly wet, and a few days later those same dark green spots appear raised into little bumps on the underside. There are also a few areas that have odd discolored bumpy areas, mainly on the underside (but one is on top). I've looked up edema, but the pictures I see do not look like what is on my plants. The one that is making new buds has just a few of these spots and the leaves look slightly dehydrated (crinkled), while the other has made a new leaf and looks firm and glossy other than the many spots that have shown up, mainly on the new leaf. Does this look like edema, pests, or something else? What should I do? Any help/advice is greatly appreciated!