It starts in the roots and can eventually move through the stems and the rest of the plant tissue.
Pythium root rot is another water mold that can infect your Pothos. It is caused by various Pythium species of fungi that attack root tips and can move through the pothos roots and up into the stems.
If your plant shows unhealthy symptoms and you suspect it has root rot, isolate it from your other plants since fungal diseases spread easily.
Rhizoctonia is a soil-borne fungus that lives everywhere outdoors in gardens and fields. The most common species that can attack your Pothos is Rhizoctonia solani on the stems and leaves.