Plants, people and the next pandemic

R-numbers, fomite versus airborne transmission, droplets versus aerosols, mRNA and viral vector vaccines. For over a year the argot of epidemiology, virology and other scientific and medical disciplines has seeped into everyday language, as people across the globe grappled with the unprecedented challenges of the COVID-19 pandemic.

Meanwhile, scientists and communicators have struggled to limit the spread of misinformation and ensure that reliable facts are what ultimately goes viral.

As the world is still fighting to handle the COVID-19 crisis, what are the messages and lessons that we must adopt now to better prepare for future challenges?

Global agriculture is a key battleground

Globalization, climate change, ecosystem degradation and biodiversity loss are key variables in the growing threat of infectious disease outbreaks. Agriculture overlaps with each of these processes and is vulnerable to the disease risks they amplify.

Former director of the International Maize and Wheat Improvement Center’s (CIMMYT) Global Wheat program, Hans Braun, recently stressed the parallel between what we have witnessed with COVID-19 and disease threats facing global agri-food systems. “The epidemiology models for humans … we see now have a lot in common with plant epidemiology,” Braun said in a conversation on wheat diseases. There are currently over 1,300 pests and pathogens known to infect agricultural crops worldwide.

“When it comes to epidemics, what applies to humans applies to plants. If there is a new race of a given crop disease, in that moment, the plant does not have a defense mechanism, like humans in the case of COVID-19, because we haven’t developed any immunity,” Braun explained.

As with a human pandemic, investments in prevention, containment and preparedness measures — such as the global wheat rust monitoring systems managed by the Borlaug Global Rust Initiative at Cornell University and CIMMYT — are of key importance. “If ‘doomsday’ happens, it will be too late to react,” Braun said. “At present, with a human pandemic, people are worried about the supply chain from food processing to the supermarket. But if we have an epidemic in plants, then we do not have the supply chain from the field to the food processing industry. And if people have nothing to eat, they will go to the streets and we will see violence. We simply cannot put this aside.”

Agriculture accounts for 30% of global GDP, yet only 5% of global research and development investment goes to the sector. “If there is any flip side to the COVID-19 disaster, it is that hopefully our governments realize that they have to play a much more serious role in many areas, in particular public health and disease control in humans but also in plants,” Braun said.

The butterfly and the bulldozer

Wheat leaf rust symptoms in the field. The fungus, Puccinia triticina, forms small reddish-orange pustules or uredinia, which rupture the upper surface of the leaf blade as the spores mature.
Wheat leaf rust symptoms in the field. The fungus, Puccinia triticina, forms small reddish-orange pustules or uredinia, which rupture the upper surface of the leaf blade as the spores mature.

The exponential growth trajectory of a disease outbreak can lead one to think of the famous butterfly effect. A single fateful encounter between a host and a pathogen can lead to world-shaking consequences. However, this overlooks how human activity is creating massive environmental and ecosystem changes that impact the likelihood and severity of future disease outbreaks.

Recently Frédéric Baudron, systems agronomist at CIMMYT, and Florian Liégeois, virologist at the Institut de Recherche pour le Développement (IRD) recalled that, “60% of infectious diseases are zoonotic, meaning that they are spread from animals to humans, and 72% of these zoonoses originate from wildlife.” They noted that biodiversity loss caused by “land use changes, generally due to changes in agricultural practices, has been the leading driver” of recent zoonotic disease outbreaks.

“There are at least three mechanisms at play,” Baudron and Liégeois explained. “First, increased contact between wildlife and humans and their livestock because of encroachment in ecosystems. Second, selection of wildlife species most able to infect humans and/or their livestock — often rodents and bats — because they thrive in human-dominated landscapes. Third, more pathogens being carried by these surviving wildlife species in simplified ecosystems. Pathogens tend to be ‘diluted’ in complex, undisturbed, ecosystems.”

Reducing the impact of our global agricultural system on biodiversity will be a gargantuan, complex task requiring a global effort like the Paris Climate Agreement, they argued. Policies incentivizing sustainable intensification and the growth of supportive markets are part of the solution. “But these measures are likely to be insufficient alone,” Baudron and Liégeois pointed out, “as a large share of the global food doesn’t enter the market but is rather consumed by the small-scale family farmers who produce it.”

CIMMYT and, by extension, CGIAR are in a position to play an important role in addressing this challenge. “Interestingly, many of these [zoonotic disease hotspots] are located in regions where CIMMYT’s activities are concentrated: Central America, East Africa and South Asia,” Baudron and Liégeois said. “This, in addition to the fact that agricultural changes are a major driver of the emergence of zoonoses, means that CIMMYT researchers may have a role to play in preventing the next global pandemic.”

Partners and funders

Borlaug Global Rust Initiative at Cornell University, CGIAR, and Institut de Recherche pour le Développement (IRD).

© 2021 International Maize and Wheat Improvement Center
We would like to thank all funders who supported this research through their contributions to the CGIAR Trust Fund.

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Marcia MacNeil, Rodrigo Ordóñez
Project coordination
Leslie Domínguez, Emma Orchardson
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Alfonso Cortés, Nancy Valtierra
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Nancy Valtierra
Web design
Ricardo López
Graphics and illustrations
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Writers and editors
Nima Chodon, Madeline Dahm, Leslie Domínguez, Alison Doody, Wasim Iftikar, G. Michael Listman, Marcia MacNeil, Steven McCutcheon, Marta Millere, Emma Orchardson
T.S. Amjath Babu, Frederic Baudron, Hans Braun, Shiela Chikulo, Olaf Erenstein, Velu Govindan, M.L. Jat, Timothy Krupnik, Sylvanus Odjo, B.M. Prasanna, Harminder S. Sidhu, Jelle Van Loon
Francisco Alarcón, Alfonso Cortés, Wasim Iftikar, Peter Lowe, Ranak Martin, S. Mojumder/Drik, Matthew O'Leary, Love Kumar Singh/BISA, F. Sipalla, Dhruba Thapa/NARC, Szefei Wong/Dreamstime, CIMMYT Archives
Silvia Rico
Correct citation
CIMMYT. 2021. Resilience. Renewal. Transition. CIMMYT Annual Report 2020. CDMX, Mexico: CIMMYT.
AGROVOC descriptors:
Maize; Wheat; Plant breeding; Genetic resources; Innovation adoption; Plant biotechnology; Seed production; Food security; Sustainability; Research policies; Economic analysis; Cropping systems; Agricultural research; Organization of research; Developing countries. Additional Keywords: CIMMYT. AGRIS category codes: A50 Agricultural Research; A01 Agriculture– General Aspects. Dewey decimal classification: 630

© International Maize and Wheat Improvement Center (CIMMYT), 2021. All rights reserved. The designations employed in the presentation of materials in this publication do not imply the expression of any opinion whatsoever on the part of CIMMYT or its contributory organizations concerning the legal status of any country, territory, city, or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries. CIMMYT encourages fair use of this material. Proper citation is requested.


Asian Development Bank
Accelerating Genetic Gains in Maize and Wheat
Australian Centre for International Agricultural Research
Bangladesh Bureau of Statistics
Bioactive food components
Borlaug Institute in South Asia
CGIAR Research Program on Climate Change, Agriculture, and Food Security
International Center for Tropical Agriculture
International Maize and Wheat Improvement Center
CIMMYT Maize Genetic Resource Lines
Carbon dioxide equivalent
Cereal Systems Initiative for South Asia
Crops to End Hunger
Ethiopian Institute of Agricultural Research
CGIAR Excellence in Breeding Platform
Executive Management Team
European Union
United Nations Food and Agriculture Organization
Farm Power and Conservation Agriculture for Sustainable Intensification
Foreign, Commonwealth & Development Office of the United Kingdom
Fusarium head blight
Innovative Applications in Analytics Award
Indian Council of Agricultural Research
International Center for Agricultural Research in the Dry Areas
International Food Policy Research Institute
International Institute for Applied Systems Analysis
International Institute of Tropical Agriculture
Institut de Recherche pour le Développement
International Rice Research Institute
Integrated Tribal Development Agency
Jiangsu Academy of Agricultural Sciences
Kenya Agricultural & Livestock Research Organization
Key performance indicators
CGIAR Research Program on Maize
Nitrous oxide
Nepal Agricultural Research Council
National Agricultural Research Systems
Odisha Rural Development and Marketing Society
Punjab Agricultural University
Program for Growth and Resilience
Mexico's Secretariat of Agriculture and Rural Development (Secretaría de Agricultura y Desarrollo Rural)
Sustainable Development Goals
Seeds of Discovery
Stress Tolerant Maize for Africa
Zimbabwe Resilience Building Fund
United Nations
United Nations Development Programme
United States Agency for International Development
United Nations World Food Programme
CGIAR Research Program on Wheat
Unless otherwise indicated, all amounts are expressed in U.S. dollars

Sustainable Development Goals

The 2030 Agenda for Sustainable Development, adopted by all United Nations (UN) Member States in 2015, provides a shared blueprint for peace and prosperity, for people and the planet. At its heart are the 17 Sustainable Development Goals (SDGs), which are an urgent call for action by all countries to achieve a better and more sustainable future for all.

The SDGs set the pathway for agricultural, social, and economic development. They address the global challenges we face, including poverty, inequality, climate change, environmental degradation, peace and justice.

CGIAR transformed its approach to ensure that its work is aligned with the ambitious goals. CIMMYT, through its research-for-development activities, contributes to empower women, reduce greenhouse gas emissions, and improve the health and nutrition of the world's poorest people.

CIMMYT’s work contributes to the following SDGs:


CIMMYT – the International Maize and Wheat Improvement Center – is the global leader in publicly-funded maize and wheat research and related farming systems. Headquartered near Mexico City, CIMMYT works with hundreds of partners throughout the developing world to sustainably increase the productivity of maize and wheat cropping systems, thus improving global food security and reducing poverty. CIMMYT is a member of the CGIAR System and leads the CGIAR Research Programs on Maize and Wheat and the Excellence in Breeding Platform. The Center receives support from national governments, foundations, development banks and other public and private agencies.

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