The browning on the leaves of my paph has been slowly getting worse. When new growth formed I hoped
it would be spared but it has started to spread there as well. I'm thinking it looks like cercospora. If so should I treat it with a fungicide? Do I need to remove the infection leaves?
Cercospora, if I'm not mistaken, tends to form circular clusters, which is not what I see in your photos.
It may be nothing more than old growth showing signs of age. I have noticed that if I get into a busy period, and ignore my plants more than I should, older growths will display such discoloration.