Inconsistent watering will stress and weaken your plant. When combined with poor-draining soil, it also creates an environment that is inviting to various species of fungi and bacteria.
The most common problem for all pothos plants is root rot caused by a fungus-like organism called black shank (Phytophthora nicotianae). This soil-borne fungal disease thrives in warm temperatures and moist soil.
Rhizoctonia root rot is another fungal disease that can kill your pothos plants. This disease spreads quickly, especially in warm, humid environments.
Bacterial wit disease is caused by several species of bacteria, such as Ralstonia solanacearum and Erwinia tracheiphila.