Brown spots on phal leaves

[turock]

Hi all, time to play Name That Spot!

I have a large phal hybrid that is one of my healthiest orchids--or was, I should say, until a mealy bug mob moved in. I recently repotted the plant and used a systemic pesticide (imidacloprid) to try and control the bugs.

Now I'm noticing many small brownish spots on the underside of the leaves. They look kind of watery but don't ooze anything when I poke them.


In some cases the spots are also visible on the top side of the leaves. They also cause the plant's tissue to be translucent in the sunlight.


I cut off the first few blemished areas I found, about three days ago. But when I checked the plant again today, two entire leaves were dotted with them. I cut off both leaves and am still seeing some spots in random places on the remaining leaves.

I've seen sunburn, insect damage, cold damage and edema, but this doesn't look like those. Could this be a reaction to the insecticide, or could I have an infection on my hands? Should I continue to hack and slash at my once-lovely plant or is there a better way to move forward?


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