| It looks to me like the crown has got wet, and then stayed wet over night. I'm not sure how much chance the growth has of surviving, but at least with Paphs it will make new growths.
I would use a sprinkle of cinnamon over the browning, others will suggest a good anti fungal you can buy local.
My best advice would be to just look out for watering getting into the crowns of growth after watering. It can be really damaging. Try and water before midday, and if water does get into the crown, I find a small piece of tissue paper (or something equally soft) gently dabbed onto the crown will help soak up the worst, and the rest should evaporate before any rot can set in. |