Fungicides are a category of chemical substances or biological products designed to control or eliminate fungi and fungal spores to prevent fungal infections in crops or other materials. They include various chemical families such as triazoles, sulfates, copper compounds, etc., with each fungicide having a different mechanism of action and structure, targeting different stages of fungal life cycles and biological pathways, such as inhibiting spore germination or disrupting cell walls. The choice and application of fungicides depend on factors such as the target fungal species, crop type, and environmental conditions.