I am living in Okinawa and have a ginger plant in a pot. It was over watered and has developed a black-brown layer on its leaves and is not thriving. I wiped it clean with a mild soapy water solution as best I can. It doesn't look like rust, as the black layer is on the top of the leaf and there are some smaller areas on the under side. Any suggestions?
Fungus on My Houseplant
Certified GKH Gardening Expert
It is sooty mold, which is often brought about by pests. Treat the plant with neem oil, which will take care of both the fungus and whatever pests may be causing it. Here is more information: https://www.gardeningknowhow.com/plant-problems/disease/how-to-get-rid-of-sooty-mold.htm