A recent FBI case involving two Chinese researchers has cast a spotlight on a fungus most people have never heard of: Fusarium graminearum. Allegedly smuggled into the United States, the fungus is being eyed as a potential agroterrorism agent. But what exactly is it, and why is it so dangerous?
A Common Yet Destructive Crop Pathogen
Fusarium graminearum is no stranger to American farms. It’s a fungal pathogen that thrives in rainy weather, especially during a crop’s flowering stage. According to Gary Bergstrom, professor emeritus of plant pathology at Cornell University, this fungus can cause billions of dollars in agricultural damage annually.
It infects grains such as wheat and corn, interfering with kernel development and slashing yields. Worse, it produces harmful substances called mycotoxins. These toxins pose a risk not just to crops, but also to the animals and people who consume them.
How It Infects Crops
In corn, for instance, F. graminearum can enter through the stalk or ear, leading to a condition known as “ear rot.” Infected kernels grow moldy, turning once-edible corn into waste.
The Mycotoxins: More Than Just Crop Damage
The fungus releases four main mycotoxins:
- Deoxynivalenol (DON): Also known as vomitoxin, it causes nausea and vomiting.
- Zearalenone: Disrupts hormonal balance and may lead to infertility in livestock, especially pigs.
- Nivalenol and Fusarenon-X: Both are cytotoxic and immunosuppressive.
These toxins can contaminate human food and animal feed, making them a major concern for food safety regulators.
Hard to Detect in Humans
While livestock poisoning from F. graminearum is typically caught by testing animal feed, diagnosing its effects in humans is much trickier. Dr. Jerrold Leikin, an expert in environmental and occupational health at the University of Illinois at Chicago, said that most hospitals lack the capability to test for these specific mycotoxins.
“It’s almost impossible to diagnose,” Dr. Leikin noted. Symptoms in people could resemble common food poisoning, making the true cause hard to trace.
Regulated But Not Risk-Free
Despite the risks, the chance of significant exposure is low in the United States due to strict regulations. The FDA caps DON levels in flour for human consumption at 1 part per million (ppm). For animal feed, the limit ranges from 5 ppm to 10 ppm, depending on the species.
DON is heat-stable, meaning it doesn’t break down during cooking. However, milling and processing may reduce its concentration. Most flour mills test for DON levels before purchasing grain. If contamination is too high, they reject the batch outright.
Should someone ingest a high dose, treatment generally involves supportive care—hydration and electrolyte management, according to Dr. Leikin.
Strict Import Controls
Bringing agricultural materials into the United States is heavily restricted. Everyday travelers cannot legally carry in fresh produce, meat, seeds, or soil.
Researchers, however, can apply for special permits through the USDA’s Animal and Plant Health Inspection Service. These permits require detailed plans for safe handling, storage, and disposal, as well as information on who will access the material.
“It’s not just about legality—it’s about practicing good science,” said Bergstrom. Proper containment protocols are essential to avoid unintended environmental release.
A Wake-Up Call for Biosecurity
The alleged smuggling incident has raised fresh concerns about agricultural biosecurity. While F. graminearum is already present in the United States, introducing new or genetically modified strains could pose serious threats to crop yields, food safety, and public health.
With global trade and travel on the rise, maintaining strict oversight of agricultural imports is more important than ever. In the meantime, scientists and policymakers alike are keeping a close watch on this destructive fungus—and how it might be used, or misused, in the future.
