Fungicides are chemical compounds used to kill or stop the growth of fungal diseases on plants. Fungus can cause serious damage to your houseplants. The following plant diseases are the result of fungal infections: black spot, botrytis (gray mold), crown, stem, & root rot, leaf spot, powdery mildew, and red blotch. Fungicides can either be contact, translaminar or systemic. The contact variety are not absorbed into the plant & only protect the plant where the spray is deposited; translaminar pass through the upper sprayed surface of the leaf to the bottom unsprayed surface; systemic are absorbed by the plant and passed by the xylem vessels through the entire plant. Most fungicides are sold in a liquid form and contain .08%-.05% sulphur. The higher the sulphur content, the more potent the product. Fungicides in powdered form are usually around 90% sulfur and are very toxic.