Global crop surveillance system, bulwark against disease

A proposed global surveillance system would act as a bulwark against diseases that threaten food crops. UF plant pathologist Karen Garrett, who is affiliated with both IFAS and the EPI, coauthored a policy paper in Science outlining a visionary system that would link existing local and national programs to identify, predict, monitor and mitigate outbreaks of emerging crop diseases.

People need passports to travel between countries, but diseases don’t. Given that only two to six percent of crops entering a country may be inspected, all it takes is for the wrong plant pathogen to be in the right place and an entire region’s crop may be at risk.

An international group of experts on plant diseases, agriculture, entomology, economics and geography envision safeguarding the world’s food security from disease outbreaks by creating a global crop surveillance system. The group, which includes UF plant pathologist Karen Garrett, met in Italy in 2018 to troubleshoot the problem, and recently published their visionary solution in a policy paper in Science.

“Currently, the quality of plant disease programs available varies a lot from one country to another,” says Garrett, who is a professor in the Institute of Food and Agricultural Sciences, and is also affiliated with the EPI.  “The goal of a global surveillance system would be to integrate programs across countries, so that nations which have better systems and nations that are building capacity would be strengthened by being part of this global system. Greater global knowledge would benefit all the members”

The team’s concept for the global surveillance system consists of five linked networks: diagnostic labs, risk assessment modeling, data standardization and management, regular expert communications and distributed operations management systems. Regional hubs would connect local networks to global ones.

Garrett’s expertise encompasses risk assessment and data analysis, as part of her work with the UF Institute for Sustainable Food Systems. Many of these surveillance system networks already exist independently in different countries, she notes, but the global surveillance system would introduce formal links to increase international coordination, standardization and communication.

 Artistic rendering of cassava mosaic virus.

Streamlining communication would be essential, Garrett says: “To get all the systems to communicate better amongst each other would be one key contribution of an integrated global surveillance system.”

Many countries have either a general/passive or a targeted/specific infrastructure capacity for detecting or monitoring. Passive surveillance systems tend to rely on regional university or governmental extension groups to report diseases brought to their attention by monitoring or industry professionals, and often have the most trained eyes at field sites, but they also tend to lack coordination scaling from local to national to global levels. The authors address strengthening this weak spot in order to capitalize on existing local expertise.

Examples of existing systems in the U.S. that would be natural components of a global crop surveillance system include the U.S. National Plant Diagnostic Network and the U.S. Animal and Plant Health Inspection Service. International partners would include CGIAR centers such as the lead institution on the Science paper, the International Center for Tropical Agriculture (CIAT), with tools for understanding disease spread such as PestDisPlace. Scientific societies supporting such a program would include associations such as the American Phytopathological Society and national societies, and the International Society for Plant Pathology.

Climate change and global trade can influence the distribution and spread of plant diseases. Even when crop diseases are identified, monitored and interventions to counter them take place, they may still re-emerge elsewhere. The authors quantify the risks to our food supply: “Worldwide, yield losses caused by pests and diseases are estimated to average 21.5 percent in wheat, 30.0 percent in rice, 22.6 percent in maize, 17.2 percent in potato, and 21.4 percent in soybean; these crops account for half of the global human calorie intake.”

To draw attention to the linked problem of plant health and global food needs, the United Nations declared 2020 the Year of Plant Health. Garrett and her coauthors hope this designation will garner support for their concept.

Cassava mosaic disease has caused widespread damage to a key crop in Africa and is currently spreading rapidly in Southeast Asia. The authors note that delays in publishing studies on it in Southeast Asia, combined with weaknesses in some local organizations, allowed the disease to spread to neighboring regions and countries even when authorities had knowledge of it. Garrett’s lab is actively working on designing recommendations for where to distribute disease-free cassava planting materials in the region based on analyzing distribution networks, where the disease is currently and where it is at risk of spreading. This is a focus of Garrett’s PhD student, Kelsey Andersen-Onofre, who is building on analyses of seed systems in Ecuador and sweet potato seed systems in Uganda for her dissertation. The new analyses start with cassava seed system studies in Southeast Asia with Erik Delaquis of CIAT and other collaborators in the region.

Garrett is careful to point out that most famines caused by crop diseases have political contexts in addition to massive crop failures. “If conditions are stable, such as politics and trade, then usually resources can be mobilized to make up for crop deficits stemming from disease,” Garrett says. One of her own ancestors moved to the U.S. following the Irish potato famine, precipitated by losses due to the disease potato late blight, so she understands the risks when crop failures occur in conjunction with societal instability.

Garrett’s lab is also currently researching regional management strategies for laurel wilt disease in avocados in Florida and Haiti. “Florida is always at risk of new plant pathogens. People talk about the heat and humidity of Florida as providing a petri dish for new pathogen invasions,” Garrett says. “But UF is very active in plant disease diagnostics and risk assessment, and the university is a regional hub for the U.S. National Plant Diagnostic Network, which is a great example of how local and regional networks can be scaled up to national and global levels.”

By: DeLene Beeland