Fungal Plant Disease
Fungal plant disease is the occurrence of plant diseases caused by fungal agents over large areas with significant impacts on crop productivity or natural habitats (adapted from Arneson, 2001 and Moore et al., 2019).
Primary reference(s)
Arneson, P.A., 2001. Plant Disease Epidemiology: Temporal Aspects. The Plant Health Instructor. (Revised 2011). Accessed 7 March 2025.
Moore, D., D. Geoffrey, G.D. Robson and A.P.J. Trinci, 2019. 21st Century Guidebook to Fungi. 2nd Edn. Accessed 7 March 2025.
Annotations
Additional scientific description
Fungi are eukaryotic organisms that have a distinct nucleus and are classified as a separate kingdom, as are animalia and plantae. They include many important species causing plant diseases of local or global significance such as blights, wilts, rots, mildews, canker, smuts or rusts. The fungus structure largely consists of filamentous strands called mycelium and reproduces through various types of spores (CABI, no date).
Fungal diseases can occur in many forms on vegetative or reproductive organs of plants. The list of widely known diseases includes many types such as anthracnose; black knot; blight including chestnut blight and late blight; canker; clubroot; damping-off; Dutch elm disease; ergot; Fusarium wilt; leaf blister; mildew including downy mildew and powdery mildew; oak wilt; rot including basal rot, grey mould rot and heart rot; rust including wheat, soybean, pine blister, coffee and cedar-apple rust; scab including apple scab; smut including loose smut and corn smut; snow mould; sooty mould; and Verticillium wilt (Encyclopaedia Britannica, no date).
Collectively, fungi and fungal-like organisms (FLOs) cause plant diseases with over 8000 species shown to cause disease. Some of the world's great famines and periods of human suffering can be blamed on plant disease-causing fungi and FLOs (Williams et al., 2017).
The most known example of a disaster caused by a fungal pathogen is the potato late blight epidemic that caused the great famine in Ireland in the 1840s. This continues to be a good example of a single disease-causing devastating losses to potatoes worldwide (Suo-meng & Shao-qun, 2022). Another example is the wheat rust disease. It is well known that the continuing challenges of wheat rust diseases date back to ancient times when a specific festival `Robigalia` was organized in relation to protecting wheat crops from the rust disease (Bhavani et al., 2022).
In addition to being agents of pre-harvest and post-harvest diseases and rots, some fungi can produce highly toxic, hallucinogenic and carcinogenic chemicals that have not only affected the lives of millions historically but also continue to cause problems today. In 2006, dozens of dogs perished from food tainted with aflatoxin, a chemical produced by several Aspergillus species. These fungi can grow on many plants such as corn and produce toxins on the grain that not only affect the liver but are also one of the most carcinogenic substances known (Williams et al., 2017).
In addition to the harmful effects of fungal plant diseases, it should also be noted that Some fungi have beneficial roles in soil, but many are the major causal agents of plant diseases both during growth and in post-harvest processing. A wide range of fungicides are used to control fungi and to avoid production losses (FAO, 2017).
Metrics and numeric limits
Not known.
Key relevant UN convention / multilateral treaty
The International Plant Protection Convention (1997) is an intergovernmental treaty signed by over 180 countries, aiming to protect the world’s plant resources from the spread and introduction of pests and promote safe trade (FAO, 2011). The Convention develops and introduces International Standards for Phytosanitary Measures as its main tool to achieve its goals, making it the sole global standard-setting body for plant health. The IPPC is one of the ‘Three Sisters’ recognised by the World Trade Organization’s (WTO) Sanitary and Phytosanitary Measures (SPS) Agreement, along with the Codex
The Codex Alimentarius (FAO and WHO, no date).
The International Health Regulations (2005), 3rd edn. (WHO, 2016).
The WTO Agreement on the Application of Sanitary and Phytosanitary Measures (SPS Agreement) (1994) (WTO, no date).
The WTO and the World Organization for Animal Health (OIE) (WTO, 1998).
Convention on Biological Diversity. (CBD, 2025). https://www.cbd.int/ Accessed on 7 March 2025.
Drivers
Favourable climatic conditions, disruption of natural balance and deficiencies in crop and forest hygiene contribute to the build-up and spread of the inoculum of fungi regularly causing substantial damage to crops, forests and other natural habitats. Prevention of spread and outbreaks is always easier than responding to epidemics and control. Adopting the principles of sustainable plant production, sustainable forest management and integrated pest management practices are critical for the control of fungal plant diseases. Specific management methods include a focus on diversified production, the use of disease-resistant varieties, the use of pathogen-free certified planting materials, regular surveillance and rapid containment at initial stages all in an integrated manner.
Fungi mutate frequently and produce new strains that might be more aggressive. Therefore, continuous surveillance and development of resistant varieties to emerging strains is critical for integrated management of fungi and fungal-like organisms.
Impacts
Many fungal disease epidemics have affected crop production and forests in many countries and regions in world history. These include epidemics caused by potato blight, wheat rust diseases, chestnut blight, rice blast and banana Fusarium wilt. Estimation regarding economic losses for the whole group of fungal diseases is limited, but there are a few studies concerning the impact of specific diseases. For example, potato late blight causing the famine in Ireland in 1840s resulted in up to 10 billion USD in yield loss and management costs (Suo-meng & Shao-qun, 2022). It is estimated that wheat rust diseases cause global annual losses can be around 15 million tons valued at US$ 2.9 billion (Huerta-Espino et al., 2020).
Fungal plant disease outbreaks may cause food security challenges especially if the staple food crops are affected. They can also result in market or price instability. One good example of this is fluctuations of cocoa prices caused by the black pod disease of cocoa in Africa in 2024 (Africanews, 2024; J.P. Morgan, 2024). Similar effects occur in other crops too in different regions, but most remain unnoticed or not reflected sufficiently in the international fora. Plant disease outbreaks can also be a great concern for job losses for farm workers as in the case of outbreaks of banana Fusarium wilt TR4 (Altendorf, 2019).
In certain cases, fungal plant diseases can also affect animal and human health directly. In general, the issues related to pesticide residues and toxic substances in feed and food may escape attention, particularly in the developing world. There have been some critical cases in history in this respect. In 2006, dozens of dogs perished from food tainted with aflatoxin, a chemical produced by several Aspergillus species. These fungi can grow on many plants such as corn and produce toxins on the grain that not only affect the liver but is also one of the most carcinogenic substances known (Williams et al., 2017).
Multi-hazard context
The figure below summarises common interactions between fungal plant diseases and other hazards. This information should be used with caution and not be solely relied upon in Disaster Risk Management, particularly as some interactions may not have been included. Note that hazardous events occurring together or locally in space or time may not necessarily cause, amplify or be otherwise related to each other. Specific examples of multi-hazard context can be found in the ‘Hazard drivers’ and ‘Impacts’ sections above.
Multi-hazard diagram
Risk Management
The missions of the International Plant Protection Convention (IPPC) cover fungal plant diseases as well as other pests and diseases. It forms an international forum providing space for intergovernmental discussions and negotiations on managing the risks resulting from the spread of plant diseases (as well as other biological agents threatening plants). It provides facilities for the establishment of international standards, capacity building and reporting for the purpose of minimizing risks of the spread of these agents.
Countries are expected to adhere to the international standards and strengthen their phytosanitary capacity and biosecurity systems. Their capacity for preparedness, monitoring and rapid response should also be strengthened. In addition, international cooperation should be established or strengthened to address the regional or global challenges related to the management of invasive and transboundary plant pests and diseases, particularly those that are airborne such as rust diseases of wheat and many types of blights and mildews of many crops.
Monitoring
The section and the table below offer an overview of monitoring for fungal plant diseases. This information can be used for forecasting within a national early warning system (EWS). Since EWS capacities and processes differ across countries, the most current and specific information regarding EWS should be obtained from the appropriate national or regional agency/authority responsible for disaster management.
| Which institution(s) produce(s) Disaster Risk Data/Information? | There are several early warning systems particularly at the regional level, for example for Europe (Peter et al., 2011) and North America (Meissner et. Al. 2015). At global level, the pest reporting system of IPPC can be considered the most official resource for reports of the occurrence of quarantine plant pests including diseases (IPPC, 2025). Although such reports are deposited well after the establishment of a pest these can be considered as early warning resources for other concerned countries. At field level, a good global monitoring system has been developed for rust diseases of wheat (Global Rust Reference Centre, Aarhus University, 2025) providing monitoring and early warning, particularly for the new races. |
| How is the Hazard Observed/Monitored/Forecast? | Looking at disease reports from countries. |
References
Altendorf, S. 2024. Banana Fusarium Wilt Tropical Race 4: A mounting threat to global banana markets? Accessed 9 March 2025.
Africanews, 2024. Accessed 9 March 2025.
Arneson, P.A., 2001. Plant Disease Epidemiology: Temporal Aspects. The Plant Health Instructor. (Revised 2011). Accessed 9 March 2025.
Bhavani, S., Singh, R.P., Hodson, D.P., Huerta-Espino, J., Randhawa, M.S., 2022. Wheat Rusts: Current Status, Prospects of Genetic Control and Integrated Approaches to Enhance Resistance Durability. In: Reynolds, M.P., Braun, HJ. (eds) Wheat Improvement. Springer, Cham. DOI: 10.1007/978-3-030-90673-3_8. Accessed 9 March 2025.
CABI, no date. Description of Fungi and bacteria. Accessed 9 March 2025.
CBD, 2025. Convention on Biological Diversity. Accessed on 7 March 2025.
Encyclopaedia Britannica, no date. List of Plant Diseases. Accessed 9 March 2025.
FAO, 2011. International Plant Protection Convention 1997. Food and Agriculture Organisation of the United Nations (FAO). Accessed 9 March 2025.
Global Rust Reference Centre, Aarhus University, 2025. Accessed 7 March 2025.
FAO, 2017. Global Assessment of the Impact of Plant Protection Products on Soil Functions and Soil Ecosystems. Food and Agriculture Organization of the United Nations (FAO). Accessed 9 March 2025.
FAO and WHO, 2025. About Codex Alimentarius. Food and Agriculture Organization of the United Nations (FAO) and World Health Organization (WHO). Accessed 9 March 2025.
Huerta-Espino J., Singh R., Crespo-Herrera L.A., Villaseñor-Mir H.E., Rodriguez-Garcia M.F., Dreisigacker S., Barcenas-Santana D., Lagudah E., 2020. Adult plant slow rusting genes confer high levels of resistance to rusts in bread wheat cultivars from Mexico. Front Plant Sci 11:1. DOI: 10.3389/fpls.2020.00824. Accessed 9 March 2025.
IPPC, 2025. Pest reporting. Accessed 7 March 2025.
J.P. Morgan, 2024. Rising cocoa prices: Will the chocolate crisis continue in 2025? Accessed 7 March 2025.
Meissner, H., Fritz, J., Kohl, L., Moylett, H., Moan, M., Emerine, S., Kaye A., 2015. PestLens: an early-warning system supporting US safeguarding against exotic plant pests. Bull. OEPP 45: 304–310.
Moore, D., Geoffrey, D., Robson, G.D., Trinci, A.P.J., 2019. 21st Century Guidebook to Fungi. 2nd Ed. Accessed 9 March 2025.
Suo-meng, D., Shao-qun, Z., 2022. Potato late blight caused by Phytophthora infestans: From molecular interactions to integrated management strategies. Journal of Interactive Agriculture, Elsevier, Vol. 21, Issue 12. Accessed 9 March 2025.
WHO, 2016. International Health Regulations (2005), 3rd ed. World Health Organization (WHO). Accessed 9 March 2025.
Williams, S.D., Boehm, M.J., Mitchell, T.K., 2017. Fungal and Fungal-like diseases of plants. Accessed 9 March 2025.