Root rot is a disease caused by fungus. Rotting of the roots keeps the plant from absorbing water and nutrients from the soil. This fungal attack is one of the most serious diseases any plant can be infected with. The early stages cause wilting of the plants leaves and discoloration. In many cases, the plant will die if measures are not taken to contain the infection. Prevention is key with root rot--once the symptoms appear, it is often too late, but there is a chance to save the plant.
Free the plant from the dirt, making sure not to damage the roots. Check the root system for excessive damage. If the roots look strong, you may pot the plant again.
Cut off excessively damaged roots, leaving healthy ones in place. This will keep the fungus from spreading further to the foliage.
Wash the old soil off of the root system to remove fungus.
Soak your old pot with a 10 percent bleach-and-water solution (1 part bleach to 9 parts water) for 30 minutes, then rinse.
Place new soil into the disinfected pot and soak the soil with thiophanate-methyl, the fungicide. This will prevent spread of the fungus from the roots into the soil and kill existing spores.
Place the plant in the soil, making sure to cover the root system properly. Water the soil lightly and ensure there is enough drainage.