Phal leaves and stem turning reddish-brown

[sweta]

One of my rescue phals has its leaves and stem turning reddish-brown suddenly. It lost all its original leaves except one since I got it. Since then it grew 3 new leaves and lots of roots. But recently leaves and stem developed a reddish-brown tinge . Any idea on what could be causing this? Could it be just sunburn? I've treated the orchid with thiomyl fungicide just in case it is some fungal infection. New leaves look healthy other than the reddish brown tinge.

[estación seca]

That's common in Phals and is a response to strong light.

I recommend not using a fungicide unless you know you have a fungus, you know which fungus it is and you know the fungus is susceptible to the fungicide you plan to use. There are beneficial fungi growing around plants that keep pathogenic fungi in check. Fungicides kill the beneficial ones, too.

Different fungi are resistant to different fungicides, so you need to be certain it will work on the fungus you have. And plants growing on a windowsill rarely develop fungi unless the relative humidity is very high.

[sweta]

Thank you for confirming that its probably due to strong light. Thats huge relief to hear that.
I agree with you on the usage of fungicide. I'm not so sure about the various diseases and that's why when I see anything wrong with the phal like patches on leaves etc I just treat it with fungicide. I dont use it on all my healthy phals but only on ones that are struggling to survive and have leaf issues. But I totally get you point and will keep this in mind to use unless I'm sure.