Two Chinese nationals are accused of attempting to smuggle a fungus into the U.S. that authorities describe as a “dangerous biological pathogen.”

Eunjing Jian, 33, and Zuniong Liu, 34, are charged with conspiracy, smuggling, making false statements and visa fraud, authorities in Michigan said.

According to the complaint, Liu attempted to smuggle the fungus through the Detroit airport to study it at a University of Michigan lab where Jane, his partner, worked.

The fungus, the BBC reports, is called Fusarium graminearum and can cause a disease in wheat, barley, maize and rice that can wipe out crops. If it gets into food, the fungus can cause vomiting and liver damage.

In the scientific literature, the fungus is described as a “potential agro-terrorist weapon” and is responsible for “billions of dollars in economic losses worldwide each year.”

U.S. officials also claim that Gian was funded by the Chinese government for her research on the pathogen in China. They also claim that she is a member of the Chinese Communist Party.

The case comes amid strained relations between the US and China centered on tariffs imposed by the Trump administration, to which Beijing has responded.