Fungicides are chemical substances used to control and prevent fungal diseases in plants. They work by either killing the fungi or inhibiting their growth and reproduction. Fungicides are commonly used in agriculture to protect crops from fungal infections, which can cause significant damage to yield and quality. There are different types of fungicides, including contact fungicides that remain on the surface of the plant and systemic fungicides that are absorbed into the plant tissue and provide longer-lasting protection. The use of fungicides in agriculture is a key tool for farmers to maintain crop health and productivity.