The world needs a global system to detect and halt the spread of crop disease

cassava leaves with mosaic disease

Cassava Mosaic Disease in Cambodia. Credit: Georgina Smith/CIAT

More than 20 percent of the five staple crops that provide half the globe’s caloric intake are lost to pests each year. Climate change and global trade drive the spread, emergence and reemergence of crop disease, and containment actions are often inefficient, especially in low-income countries.

A Global Surveillance System (GSS) to improve and interconnect crop biosecurity systems could go a long way in improving global food security, argues a team of researchers in the journal Science. The team includes University Distinguished Professor Jan Leach, associate dean for research and a plant pathologist in the College of Agricultural Sciences.

“This work summarizes a strategy for how the world can be better prepared for the introduction and spread of pathogenic microbes in important crop systems,” Leach said.

Leach and colleagues say the GSS framework they propose should gain traction in 2020, which was designated International Year of Plant Health by the United Nations. The GSS aims to bring together the more than 180 member nations of the International Plant Protection Convention (IPPC), with a focus on countries at high risk relative to their ability to respond.

The system would prioritize six major food crops – maize, potato, cassava, rice, beans, and wheat – as well as other important food and cash crops that are traded across borders. The GSS proposal is the result of a scientific meeting convened by the International Center for Tropical Agriculture and held in 2018 at the Rockefeller Foundation’s Bellagio Center in Italy.

“As part of efforts to satisfy global demand for food – which could mean increasing agricultural production by as much as 70 percent by 2050 – we need a GSS to reduce food lost to pests,” said Mónica Carvajal, a researcher at the International Center for Tropical Agriculture (CIAT) and lead author. “A lot of collaboration and discussion is needed to improve existing systems so we can avoid outbreaks that could negatively impact food security and trade.”

Inspired by recent outbreaks

In 2015, researchers from China discovered Cassava Mosaic Disease (CMD) in Cambodia but did not publish their findings until 2016. By 2018, the disease had spread to Thailand and Vietnam, and is now estimated to be present in 10 percent of the surfaces cultivated in the region, threatening millions of smallholders who cultivate cassava and generate $4 billion in export revenue.

This year, agricultural authorities from four countries, supported by research organizations including CIAT, published an emergency control plan for CMD in Southeast Asia.

The GSS proposal includes specialists who studied the wheat blast outbreak that hit Bangladesh in 2016 and the bacterial outbreak of Xylella fastidiosa that started affecting olive trees in Europe in 2013. Experts on human epidemics also formed part of the research team, as well as members of the U.S. National Plant Diagnostic Network, the European and Mediterranean Plant Protection Organization, the French National Research Institute for Sustainable Development, the U.S. Agency for International Development, and numerous university and research institutions.

What would GSS do?

The GSS would focus on tightening networks’ “active surveillance” and “passive surveillance” personnel who are on the front lines of disease outbreaks. Active surveillance consists of labs at agriculture inspection stations, and customs and phytosanitary inspectors at borders and ports of entry. Despite their formal infrastructure, only an estimated 2-6 percent of cargo can be effectively screened.

The second group includes loose networks of farmers; extension workers with national agricultural organizations; scientists and agronomists at research centers and universities; and specialists in agriculture industries.

“For this infrastructure to be effective, connections between first detectors and downstream responders must be well coordinated,” the authors write. “But diagnosis capacity, information sharing and communications protocols are lacking or weakly established in most regions. Our reflection on many disease outbreaks is that whether in high-income countries or low-income countries, the passive surveillance infrastructure has the most in-field monitoring and trained eyes but the least coordination from local to global.”

The GSS would tap into cutting-edge technology for rapid disease diagnostics and take advantage of communications networks, including social media, to rapidly share information. The system would have regional hubs and consist of five formal global networks. These would include a diagnostic laboratory network, a risk assessment network, a data management network, an operational management network and a communications network.

The GSS would seek to establish reporting and rapid communications protocols in the same manner that the World Health Organization shares information on global human disease outbreaks.

Researchers plan to work with the United Nations Food and Agriculture Organization’s International Plant Protection Convention agenda for 2020-30 to make the GSS a reality.

CSU University Communications Staff