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funder_partner: Brazilian Agricultural Research Corporation (Embrapa)

Wheat blast spread globally under climate change modeled for the first time

Written by Julian Bañuelos-Uribe on . Posted in News, Press releases.

Climate change poses a threat to yields and food security worldwide, with plant diseases as one of the main risks. An international team of researchers, surrounding professor Senthold Asseng from the Technical University of Munich (TUM), has now shown that further spread of the fungal disease wheat blast could reduce global wheat production by 13% until 2050. The result is dramatic for global food security.

With a global cultivation area of 222 million hectares and a harvest volume of 779 million tons, wheat is an essential food crop. Like all plant species, it is also struggling with diseases that are spreading more rapidly compared to a few years ago because of climate change. One of these is wheat blast. In warm and humid regions, the fungus magnaporthe oryzae has become a serious threat to wheat production since it was first observed in 1985. It initially spread from Brazil to neighboring countries. The first cases outside of South America occurred in Bangladesh in 2016 and in Zambia in 2018. Researchers from Germany, Mexico, Bangladesh, the United States, and Brazil have now modeled for the first time how wheat blast will spread in the future.

Wheat fields affected by wheat blast fungal disease in Passo Fundo, Rio Grande do Sul, Brazil. (Photo: Paulo Ernani Peres Ferreira)

Regionally up to 75% of total wheat acreage affected

According to the researchers, South America, southern Africa, and Asia will be the regions most affected by the future spread of the disease. Up to 75% of the area under wheat cultivation in Africa and South America could be at risk in the future. According to the predictions, wheat blast will also continue to spread in countries that were previously only slightly impacted, including Argentina, Zambia, and Bangladesh. The fungus is also penetrating countries that were previously untouched. These include Uruguay, Central America, the southeastern US, East Africa, India, and eastern Australia. According to the model, the risk is low in Europe and East Asia—with the exception of Italy, southern France, Spain, and the warm and humid regions of southeast China. Conversely, where climate change leads to drier conditions with more frequent periods of heat above 35 °C, the risk of wheat blast may also decrease. However, in these cases, heat stress decreases the yield potential.

Wheat fields affected by wheat blast fungal disease in Passo Fundo, Rio Grande do Sul, Brazil. (Photo: Paulo Ernani Peres Ferreira)

Dramatic yield losses call for adapted management

The affected regions are among the areas most severely impacted by the direct consequences of climate change. Food insecurity is already a significant challenge in these areas and the demand for wheat continues to rise, especially in urban areas. In many regions, farmers will have to switch to more robust crops to avoid crop failures and financial losses. In the midwest of Brazil, for example, wheat is increasingly being replaced by maize. Another important strategy against future yield losses is breeding resistant wheat varieties. CIMMYT in collaboration with NARs partners have released several wheat blast-resistant varieties which have been helpful in mitigating the effect of wheat blast. With the right sowing date, wheat blast-promoting conditions can be avoided during the ear emergence phase. Combined with other measures, this has proven to be successful. In more specific terms, this means avoiding early sowing in central Brazil and late sowing in Bangladesh.

First study on yield losses due to wheat blast

Previous studies on yield changes due to climate change mainly considered the direct effects of climate change such as rising temperatures, changing precipitation patterns, and increased CO2 emissions in the atmosphere. Studies on fungal diseases have so far ignored wheat blast. For their study, the researchers focused on the influence of wheat blast on production by combining a simulation model for wheat growth and yield with a newly developed wheat blast model. Environmental conditions such as the weather are thus included in the calculations, as is data on plant growth. In this way, the scientists are modeling the disease pressure in the particularly sensitive phase when the ear matures. The study focused on the influence of wheat blast on production. Other consequences of climate change could further reduce yields.

Read the full article.

Further information:

The study was conducted by researchers from:

  • CIMMYT (Mexico and Bangladesh)
  • Technical University of Munich (Germany)
  • University of Florida (United States)
  • Brazilian Agricultural Research Corporation (Brazil)
  • International Fertilizer Development Center (United States)
  • International Food Policy Research Institute (United States)
The grain in this blast-blighted wheat head has been turned to chaff. (Photo: CKnight/DGGW/ Cornell University)

Preventing and protecting against wheat blast

Written by Emma Orchardson on . Posted in News.

A blast-blighted stalk of wheat. (Photo: Chris Knight/Cornell)

Every year, the spores of the wheat blast fungus lie in wait on farms in South America, Bangladesh, and beyond. In most years, the pathogen has only a small impact on the countries’ wheat crops. But the disease spreads quickly, and when the conditions are right there’s a risk of a large outbreak — which can pose a serious threat to the food security and livelihood of farmers in a specific year.

To minimize this risk, an international partnership of researchers and organizations have created the wheat blast Early Warning System (EWS), a digital platform that notifies farmers and officials when weather conditions are ideal for the fungus to spread. The team, which began its work in Bangladesh, is now introducing the technology to Brazil — the country where wheat blast was originally discovered in 1985.

The International Maize and Wheat Improvement Center (CIMMYT), the Brazilian Agricultural Research Corporation (EMBRAPA),  Brazil’s University of Passo Fundo (UPF) and others developed the tool with support from USAID under the Cereal Systems Initiative for South Asia (CSISA) project.

Although first developed with the help of Brazilian scientists for Bangladesh, the EWS has now come full circle and is endorsed and being used by agriculture workers in Brazil. The team hopes that the system will give farmers time to take preventative measures against the disease.

Outbreaks can massively reduce crop yields, if no preventative actions are taken.

“It can be very severe. It can cause a lot of damage,” says Maurício Fernandes, a plant epidemiologist with EMBRAPA.

Striking first

In order to expand into a full outbreak, wheat blast requires specific temperature and humidity conditions. So, Fernandes and his team developed a digital platform that runs weather data through an algorithm to determine the times and places in which outbreaks are likely to occur.

If the system sees a region is going to grow hot and humid enough for the fungus to thrive, it sends an automated message to the agriculture workers in the area. These messages — texts or emails — alert them to take preemptive measures against the disease.

More than 6,000 extension agents in Bangladesh have already signed up for disease early warnings.

In Brazil, Fernandes and his peers are connecting with farmer cooperatives. These groups, which count a majority of Brazilian farmers as members, can send weather data to help inform the EWS, and can spread  alerts through their websites or in-house applications.

Wheat blast can attack a plant quickly, shriveling and deforming the grain in less than a week from the first symptoms. Advance warnings are essential to mitigate losses. The alerts sent out will recommend that farmers apply fungicide, which only works when applied before infection.

“If the pathogen has already affected the plant, the fungicides will have no effect,” Fernandes says.

A blast from the past

Because wheat had not previously been exposed to Magnaporthe oryzae,  most wheat cultivars at the time had no natural resistance to Magnaporthe oryzae, according to Fernandes.  Some newer varieties are moderately resistant to the disease, but the availability of sufficient seed for farmers remains limited.

The pathogen can spread through leftover infected seeds and crop residue. But its spores can also travel vast distances through the air.

If the fungus spreads and infects enough plants, it can wreak havoc over large areas. In the 1990s — shortly after its discovery — wheat blast impacted around three million hectares of wheat in South America. Back in 2016, the disease appeared in Bangladesh and South Asia for the first time, and the resulting outbreak covered around 15,000 hectares of land. CGIAR estimates that the disease has the potential to reduce the region’s wheat production by 85 million tons.

In Brazil, wheat blast outbreaks can have a marked impact on the country’s agricultural output. During a major outbreak in 2009, the disease affected as many as three million hectares of crops in South America. As such, the EWS is an invaluable tool to support food security and farmer livelihoods. Fernandes notes that affected regions can go multiple years between large outbreaks, but the threat remains.

“People forget about the disease, then you have an outbreak again,” he says.

Essential partnerships

The EWS has its roots in Brazil. In 2017 Fernandes and his peers published a piece of research proposing the model. After that, Tim Krupnik, a senior scientist and country representative with CIMMYT in Bangladesh, along with a group of researchers and organizations, launched a pilot project in Bangladesh.

There, agriculture extension officers received an automated email or text message when weather conditions were ideal for wheat blast to thrive and spread. The team used this proof of concept to bring it back to Brazil.

According to Krupnik, the Brazil platform is something of a “homecoming” for this work. He also notes that cooperation between the researchers, organizations and agriculture workers in Brazil and Bangladesh was instrumental in creating the system.

“From this, we’re able to have a partnership that I think will have a significant outcome in Brazil, from a relatively small investment in research supplied in Bangladesh. That shows you the power of partnerships and how solutions can be found to pressing agricultural problems through collaborative science, across continents,” he says.

Read more: Towards an early warning system for wheat blast: epidemiological basis and model development

Fall Armyworm R4D and Management

Written by Emma Orchardson on . Posted in Uncategorized.

The fall armyworm (Spodoptera frugiperda; FAW), an insect-pest native to the Americas, has been a persistent and serious pest of maize for over a century. Public and private sector scientists in the Americas – particularly in Brazil and the United States – have developed and deployed effective strategies to control the pest.

Incidence of fall armyworm was first reported in Nigeria in January 2016, and subsequently in over 40 countries across Africa. In Asia, the pest was first reported in India in mid-2018, and has since emerged in several countries in the Asia-Pacific. Strategies for fall armyworm management in both Africa and the Asia-Pacific can benefit immensely from those already fine-tuned in the Americas, with necessary customization to fit local agroecologies and farming systems. There is also a need to intensively work on various aspects of integrated pest management (IPM) for effective and sustainable fall armyworm management. This includes Research-for-Development (R4D) for discovering, validating and piloting best-bet technological interventions or management practices.

This project brings together the expertise of key institutions with long-standing experience in effectively dealing with transboundary insect-pests to strengthen the capacities of Africa- and Asia-based institutions in fall armyworm management. The goal is to develop and disseminate comprehensive, expert approved, IPM-based fall armyworm pest management practices that will enable various stakeholders – especially farmers, extension agents, and pest control advisors – to effectively scout, determine the need for, and appropriately apply specific interventions to control the fall armyworm in maize and other crops in Africa and Asia.

Objectives

  • Develop, publish and disseminate comprehensive, expert-approved, IPM-based information resources for various stakeholder groups
  • Integrate traits for fall armyworm resistance into the CIMMYT breeding pipeline
  • Establish a fall armyworm Research-for-Development (R4D) Consortium