Wheat is one of the most important staple crops in the world, providing food and income for billions of people. However, wheat production is facing a serious challenge from fusarium blight, a fungal disease that infects wheat ears and reduces grain quality and yield. It also produces mycotoxins, which are harmful to human and animal health. The fungus is influenced by weather conditions, especially temperature and rainfall, and is expected to worsen under climate change scenarios. This spotlight examines the current and projected impacts of fusarium blight on wheat production, prices, and security, and discusses the political implications.

Current Impacts of Fusarium Blight

Fusarium blight is a widespread and devastating disease of wheat, affecting all major wheat-producing regions in the world. The fungus lowers yields and reduces the quality of wheat grains by lowering their test weight, protein content, and germination rate. It also contaminates wheat grains with mycotoxins, such as deoxynivalenol (DON) and zearalenone (ZEA), which can cause acute and chronic health problems in humans and animals, such as vomiting, diarrhoea, reproductive disorders, immune suppression, and cancer. This presence of mycotoxins in wheat affects its marketability and trade, as many countries have set maximum allowable levels for mycotoxins in food and feed.

Fusarium blight outbreaks are highly variable and depend on several factors, such as the susceptibility of wheat cultivars, the timing and duration of flowering, and the weather conditions during flowering and post-flowering. Warm, wet, humid conditions during flowering favour infection by fusarium species, causing ear blights and seed-borne infection. Further rainfall and humid conditions allow secondary infections to occur, allowing further fungal growth and mycotoxin production. Therefore, fusarium blight epidemics are often associated with wet seasons or regions with high rainfall or irrigation.

In terms of specific numbers, the FHB epidemic has been reported to lead to a 10–70% of production loss during epidemic years. For example, in China, a 5–10% yield loss is common due to FHB, but it can reach up to 100% in epidemic years, affecting around 7 million hectares of wheat fields.

These factors can create a supply shortage, which in turn can drive up the price of wheat in the commodity market. However, the exact impact on wheat prices can vary depending on a range of factors, including the severity of the outbreak, the region’s reliance on wheat production, and the global wheat market conditions at the time of the outbreak.

Winter Wheat

Commodity wheat, sometimes referred to as winter or common wheat , accounts for the vast majority of production worldwide as it contains higher protein than other varieties, this allows for a wider range of uses and a higher number of possible products produced from the wheat itself. Winter wheat is planted in the autumn and harvested in the following summer. It is grown in temperate regions of the world, such as Europe, North America, China, and India. Winter wheat also provides soil cover and erosion control during the winter months.

Blight is much more common in winter wheat than in spring wheat because winter wheat has a longer exposure to the risk factors that favour fusarium infection. These risk factors include warm and humid weather during flowering, and susceptible varieties. Winter wheat also tends to flower earlier than spring wheat, which coincides with the peak period of fusarium spore production and dispersal.

Projected Impacts of Fusarium Blight under Climate Change

Climate change is expected to increase the frequency and intensity of extreme weather events, such as heat waves, droughts, floods, storms, and hail. These events can directly affect wheat production by damaging crops or reducing yields. However, climate change can also indirectly affect wheat production by altering the distribution and severity of plant diseases, such as fusarium blight.

The extent to which fusarium blight may affect the prices of winter wheat depends on several factors, such as the magnitude and frequency of fusarium epidemics, the availability and cost of fungicides and resistant varieties, the demand and supply of wheat in the global market, and the regulations and standards for mycotoxin contamination. Fusarium blight can reduce the quantity and quality of winter wheat, which may lower its market value and increase its production costs. Fusarium blight may also pose a threat to food safety and security, as mycotoxins can cause adverse health effects in humans and animals. Therefore, fusarium blight can have negative impacts on the income and welfare of farmers, consumers, processors, traders, and regulators.

Several studies have projected the impacts of climate change on fusarium blight using crop models coupled with disease models and climate scenarios. The results vary depending on the location, time horizon, emission scenario, and model assumptions. However, some general trends can be observed:

• Climate change will advance wheat anthesis dates, the stage of the wheat life cycle that allows for full flowering, it is at this stage that wheat is vulnerable to blight and rainfall during this period is predictive of incidents of blight. Due to higher temperatures and shorter growing seasons this may reduce the exposure of wheat to fusarium infection during flowering, as the peak of infection may occur before or after anthesis. However, this may also increase the risk of heat stress and drought stress during grain filling, which can reduce wheat yields and quality.

• Climate change will increase the incidence and severity of fusarium blight in regions where rainfall and humidity are projected to increase, especially during flowering. This may enhance the infection by fusarium species and the production of mycotoxins in wheat grains. However, this may also reduce the risk of water stress and increase the water use efficiency of wheat crops.

• Climate change will decrease the incidence and severity of fusarium blight in regions where rainfall and humidity are projected to decrease, especially during flowering. This may reduce the infection by fusarium species and the production of mycotoxins in wheat grains. However, this may also increase the risk of water stress and reduce the water use efficiency of wheat crops.

Implications for Wheat Prices and Security

The impacts of fusarium blight on wheat production, quality, and trade have significant implications for wheat prices and security. Wheat prices are determined by the interaction of supply and demand factors in global markets. Supply factors include production, stocks, trade policies, weather shocks, and diseases. Demand factors include consumption, income, population growth, preferences, and biofuel policies. Wheat security refers to the availability, accessibility, utilisation, and stability of wheat for food and feed purposes.

Fusarium blight can affect both supply and demand factors of wheat prices and security. On the supply side, fusarium blight can reduce wheat production by lowering yields and quality. This can create a supply shortage in domestic or international markets, leading to higher prices. Fusarium blight can also affect wheat trade by reducing exports or increasing imports. This can create a trade imbalance or a trade disruption in regional or global markets, leading to price volatility. Fusarium blight can also affect wheat stocks by reducing storage or increasing disposal. This can create a stock depletion or a stock accumulation in national or global markets, leading to price instability.

On the demand side, fusarium blight can reduce wheat consumption by lowering preferences or increasing health risks, even as states maintain high standards, the share of global wheat that meets those standards will decrease thereby decreasing supply and decreasing the amount of high quality wheat products available to consumers. This can create a demand decline in domestic or international markets, leading to lower prices. 

On the supply side, fusarium blight can also affect wheat income by reducing profits or increasing costs. This can create an income loss or an income transfer in producer or consumer groups, leading to price inequality. Fusarium blight can also affect wheat population by reducing growth or increasing mortality. This can create a wheat population decrease or a population displacement in rural or urban areas, leading to price insecurity.

Wider Consequences and Political Risk

The wider consequences of fusarium blight in winter wheat are related to its potential effects on food security, public health, trade, and environment. Fusarium blight can reduce the availability and accessibility of wheat as a staple food for millions of people around the world. Fusarium blight can also compromise the nutritional quality and safety of wheat products due to mycotoxin contamination. Fusarium blight can affect the trade relations between countries that produce or import winter wheat, as different countries may have different standards and regulations for mycotoxin levels. Fusarium blight can also have environmental implications, as it may increase the use of fungicides that can have negative effects on biodiversity and water quality.

The political risk of fusarium blight in winter wheat can be explained as the possibility of conflicts or disputes arising from the different interests and perspectives of various stakeholders involved in the production, consumption, and trade of wheat. For example, fusarium blight can create tensions between wheat exporters and importers, as the former may face lower demand and higher costs due to quality issues, while the latter may face higher prices and lower supply due to scarcity issues. Fusarium blight can also create challenges for policymakers and regulators, as they have to balance the needs and expectations of different groups, such as farmers, consumers, processors, traders, and environmentalists. Fusarium blight can also affect the stability and security of regions or countries that depend heavily on wheat as a food source, as it can cause food shortages, malnutrition, and health problems. Fusarium blight can also trigger social unrest or violence, as people may protest or riot against the authorities or other groups for their perceived failures or injustices related to wheat production or distribution.

Conclusion

In conclusion, fusarium blight emerges as a looming threat to global wheat production and security, with its multifaceted impacts on yield, grain quality, human and animal health, and international trade. The intertwined relationship between fusarium blight and climate change exacerbates the challenge, requiring comprehensive and adaptive strategies. Beyond its immediate economic consequences, the disease's far-reaching effects on food security, public health, trade relations, and environmental sustainability underscore the urgency for collaborative international efforts. Addressing fusarium blight demands not only innovative agricultural practices, resistant crop varieties, and stringent regulatory standards but also necessitates a holistic approach, involving policymakers, researchers, farmers, and consumers to ensure the resilience of global wheat production systems in the face of this pressing threat.