Lexington, Ky. – Extension faculty at the University of Kentucky Martin-Gatton College of Agriculture, Food and Environment are advancing the fight against Fusarium head blight (FHB) in hemp. This disease, caused by multiple species of the Fusarium fungus, threatens hemp crops nationwide. As hemp becomes increasingly important for grain, fiber and cannabinoid production, effective disease management has never been more critical.

FHB leads to the death of plant tissues in hemp seed heads and floral structures, significantly impacting crop quality and yield. With hemp’s expanded use – particularly in animal feed – UK’s research is essential for ensuring product quality and safety.

While research is still in progress, the team has uncovered that the Fusarium species affecting hemp are the same as those causing head blight in wheat, barley and other cereal crops. This raises concerns about potential cross-infection between hemp and cereal crops in regions where both are grown.

“Our preliminary findings suggest that crop rotations involving hemp and wheat need to be reconsidered,” said Nicole Gauthier, hemp extension plant pathologist and Department of Plant Pathology extension professor. Gauthier is also a member of the UK Hemp Research, Extension, and Education program and editor of the Compendium of Cannabis Diseases. “The risk of Fusarium spreading between these crops could impact both yields and quality.”

The team has also documented early infections in hemp, with some occurring months before visible symptoms develop. This poses a challenge for farmers, as the disease can go undetected until significant damage has occurred.

“Infections can begin long before symptoms are noticeable, which makes early detection difficult,” Gauthier said. “But it also means there’s a window for intervention that could prevent the disease from spreading further.”

One of the main concerns in the research is that the Fusarium fungi can produce harmful chemicals called mycotoxins, such as DON and T-2. These compounds pose risks to human and animal health, making their presence in hemp particularly concerning for producers in the animal feed market.

“As hemp becomes more widely used in animal feed, it’s essential to ensure that crops are free from harmful mycotoxins,” Gauthier said. “Our research confirms that mycotoxins are produced in Fusarium-infected hemp, and further work is needed to understand the full scope of the risk.”

Beyond field infections, researchers believe that Fusarium contamination could persist in stored hemp. This raises questions about current storage practices and the risk of further contamination during processing.

“It’s looking like Fusarium can survive in stored hemp, impacting product quality even after harvest,” Gauthier said. “This highlights the importance of careful post-harvest management.”

The research team’s long-term goals include developing hemp cultivars resistant to Fusarium head blight and investigating potential fungicide treatments. Currently, no fungicides are approved for use on hemp for this disease, and resistant cultivars have yet to be developed. However, the UK Hemp Research, Extension and Education program’s ongoing work is helping to lay the groundwork for these solutions.

Visit the UK Hemp Research, Extension and Education program at Martin-Gatton CAFE at hemp.ca.uky.edu.