Pathogen

Definition of Pathogen

A pathogen is a biological agent capable of causing disease in plants, animals, or humans by disrupting normal physiological processes. In agricultural and environmental contexts, pathogens include fungi, bacteria, viruses, nematodes, and other microorganisms that infect crops or livestock, leading to reduced growth, yield losses, or quality degradation.

Pathogens spread through soil, water, air, seed, insects, and direct contact, making their management a central concern in crop protection, biosecurity, and sustainable food production.

Why Pathogens Matter

Pathogens matter because they are a major source of risk to food security, farm productivity, and ecosystem health. Their impacts include:

• Crop yield and quality losses caused by plant diseases

• Increased production costs due to disease control measures

• Threats to livestock health and welfare

• Food supply disruptions at local and global scales

• Heightened vulnerability under climate change, as warmer and wetter conditions can favour pathogen spread

Understanding pathogens is essential for effective disease prevention, early detection, and integrated management strategies.

Key Characteristics of Pathogens

• Diverse Types – Including fungal, bacterial, viral, and parasitic organisms

• Host Dependence – Require a host organism to survive and reproduce

• Transmission Pathways – Spread via soil, water, air, vectors, or contaminated equipment

• Environmental Sensitivity – Influenced by temperature, humidity, and soil conditions

• Host Specificity – Some pathogens target specific crops or species

• Adaptability – Ability to evolve and overcome host resistance

• Disease Expression – Cause symptoms such as wilting, rot, lesions, or stunted growth

Related Terms

• Plant Disease

• Fungicides

• Insecticides

• Biocontrol

• Integrated Pest Management (IPM)

• Crop Protection

Useful Resources on Pathogens

Explore these authoritative resources to learn more about pathogens, plant disease, and agricultural biosecurity:

• FAO – Plant Health and Biosecurity – Global guidance on pathogen prevention, surveillance, and control.

• USDA – Plant Disease and Pathogen Resources – Research and extension materials on agricultural pathogens.

• AGRIS – Plant Pathology Research Database – Peer-reviewed scientific literature on pathogens and disease control.

• European and Mediterranean Plant Protection Organization (EPPO) – Standards and alerts related to plant pathogens.

• DEFRA – Plant Health and Disease Control (UK) – Official guidance on managing plant pathogens and biosecurity risks.

• International Society for Plant Pathology (ISPP) – Research, publications, and global collaboration on plant disease science.

• IPPC – International Plant Protection Convention – Global framework for preventing the spread of plant pests and pathogens.

• Plant Health Alliance - Guidance documents on plant biosecurity.