Examples of bioterrorism or agroterrorism are extremely rarely clearly documented – the field is often characterized by covert operations, political accusations and innuendo. The case of Fusarium graminearum is the best-documented example to date of suspected Chinese-sponsored bioterrorism against Western democracies.
In July 2024, customs officers at Detroit Metropolitan Airport searched Zunyong Liu, 34, a biologist at Hangzhou University in southeast China, after he landed. His luggage contained crumpled tissues, filter paper with cryptic circles, and four plastic bags containing reddish-brown plant material. But these were not harmless samples, but Fusarium graminearum, a pathogen that U.S. authorities have classified as a “potential agroterrorism weapon” capable of destroying entire crops and poisoning both animals and humans.
Agroterrorism at the airport?
Liu initially claimed he had come to visit his girlfriend, Yunqing Jian, who was a postdoctoral fellow at the University of Michigan. However, under pressure from investigators, he eventually admitted that he had intentionally hidden the samples in order to clone them in the lab and use them for further research. On Liu’s cell phone, FBI investigators found relevant literature on “plant pathogen warfare” and recordings of conversations with Jian—evidence of coordinated smuggling plans and previous attempts to import prohibited samples.
His girlfriend, Gian, also quickly came into the spotlight: According to the FBI, she is loyal to the Communist Party and is investigating the same pathogens in Michigan. Investigators have charged the couple with conspiracy, smuggling, and visa fraud.
While Liu was deported directly to China and remained beyond the reach of American justice, Jian remained in custody awaiting a bail hearing.
"Serious national security concerns"
Back in 2020, several US states warned about unsolicited packages from China that citizens were receiving. Authorities expressed suspicion that the packages could contain unknown seeds or invasive plant species. “Invasive species destroy the environment, suppress or destroy native plants and insects, and cause serious damage to crops,” according to a press release from the Virginia Department of Agriculture dated July 24, 2020.
There is now growing concern in the United States that what began as a scientific exchange is actually part of a covert strategy to weaken American agriculture by a strategic competitor.
Security experts and politicians are talking about “serious national security concerns” – last year’s case has become a prime example of a new bioterrorism threat in the era of hybrid warfare: targeted attacks on food production by introducing or deliberately modifying dangerous pathogens.
However, Fusarium graminearum has already become established in the US. It causes grain rot in wheat and barley, and ear rot in corn. However, the real danger would be the genetically modified variant against which nothing could be done. So far, there is no evidence that the smuggled samples are genetically modified, but the danger is real and frightening.
Biotechnology and artificial intelligence – a new dimension of danger
In addition to traditional smuggling methods, the possibility of optimizing pests using synthetic biology or protein design with artificial intelligence is gaining importance. Scientists have long warned that tools for modifying fungi, spores, viruses and toxic proteins could serve not only peaceful but also potentially warlike purposes.
The situation is made worse by the fact that current security mechanisms are not sufficient. A recent study shows that modern artificial intelligence models can generate dangerous protein variants that pass through conventional controls unnoticed.
"Proteins generated by artificial intelligence can have properties comparable to those found in nature, but differ in their DNA sequence. If the protein is potentially dangerous, control systems will 'overlook' the danger," explains Birte Platov, a professor at the Technical University of Dresden in Germany.
Gaps in the production of proteins generated by artificial intelligence
“Protein engineering is a research with a possible dual purpose. Therefore, it can have extremely positive effects, for example in the development of vaccines, gene-based therapies, individualized diagnostic and therapeutic concepts, as well as in the treatment of diseases for which there are currently few or no available treatments,” says Platov. “At the same time, this research is very risky, because the same technology is associated with potentially harmful consequences – such as the unintentional or intentional synthesis of genes encoding dangerous proteins, for example, for the development of biological warfare agents,” she adds.
The German expert council also confirms that dual-use technologies, and in particular the design of proteins with the help of artificial intelligence, technically facilitate attacks on critical infrastructure, agriculture and supply chains.
Underestimated threat of bioterrorism
To date, forensic evidence of actual attacks is rare. However, the changing nature of the threat is forcing Western democracies to be on guard. The combination of AI-assisted protein design, dual-use concerns, and shortcomings in risk assessment is creating a new dimension for agroterrorism and bioterrorism.
As the case of Yunqing Jian and Zunyong Liu shows, attacks on a country no longer have to be carried out exclusively by traditional means – they have long included microbiological means. The next major crisis could begin quite unnoticed – where control over fungal spores and genome variants ceases.
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