Fungus is a plant; a microscopic mushroom that infects unprotected wood. Once the wood is infected, fungus grows and decays the wood where moisture and oxygen are present. Treating decayed wood does not remove the damage. Repairing or replacing infested wood with good quality material and repairs is the only way to eliminate damaged areas. Using pressure treated lumber in exterior or moist environments is best. On minor and/or dormant fungi infested areas, application of Bora-Care or Tim-Bor and keeping the area dry will deter further fungal activity.