Overview

A fungicide is any substance or mixture intended to prevent, destroy, repel or mitigate fungi or their effects. Fungicides are used in agriculture, horticulture, forestry, and building maintenance to manage fungal diseases that damage crops, ornamentals, timber and structures. They include synthetic chemicals, natural compounds and biological controls.

Types and modes of action

Fungicides can be classified by chemistry, site of action and timing of application. Common categories include contact fungicides, which act where they are applied; systemic fungicides, which are absorbed and transported within the plant; and biological fungicides, based on living organisms or natural metabolites. Modes of action target fungal cell walls, membranes, respiration, or reproduction to inhibit growth or kill the pathogen.

Uses and application methods

Applications range from seed treatments and foliar sprays to soil drenches and trunk injections. Typical uses are:

  • Protecting crops from leaf and fruit diseases
  • Preserving harvested produce during storage
  • Controlling wood-decay and mold in buildings
  • Managing nursery and turf diseases

Safety, regulation and environmental impact

Fungicides are regulated to reduce risks to human health, non-target organisms and the environment. Proper selection, dosage and timing help limit residues and runoff. Some fungicides can affect beneficial fungi, pollinators or aquatic life, so integrated pest management (IPM) approaches and label instructions are important to minimize harm.

Resistance and best practices

Repeated use of a single fungicide class can select for resistant pathogen strains. Rotating active ingredients with different modes of action, combining cultural controls (crop rotation, resistant varieties, sanitation) and using biological alternatives reduces resistance pressure and maintains long-term effectiveness.

Further information

For regulatory guidance, safety data and technical details consult product labels and authoritative sources. A general introduction to the topic is available through resources such as further reading on fungicides.