What is wrong with this Phalaenopsis leaf?

[DenmanNJ]

Originally Posted by estación seca

This kind of Phal, with stems producing flowers for many months to years, likes high temperatures and humidity. It is susceptible to spider mites. I would check for spider mites. I would also wonder about physical damage - bumping or scraping the leaf, or sunburn.

Take a tissue, press it under a leaf near the stem, and run it to the leaf tip. With spider mites you will see brown or red streaks. They also often leave very fine cobwebs under the leaves.

Treatment is a stiff spray of water, 70% alcohol or dish soap solution (1 tsp /5ml in a quart /liter of water.) You need to treat every few days for 3-4 treatments to get them all.0

No signs of spider mites. I spoke with a friend of mine who grows orchids in his greenhouse - he said this Phal exhibits signs of sun damage. So I treated it with Epsom salts and moved it away from the window.