Peace lilies and their common counterparts are normally pretty care free. If you are growing them in containers, suggest you check for proper drainage by removing the lily and look for circling roots that are plugging pots drainage holes. If repotting then, cut away rotted and damaged roots and repot using completely new potting soil. There are fungicide drenches to control the rot organism, yet unless the conditions in the soil improve, rot will continue or return. Contact your local Extension office for a list of approved fungicides in Alabama.