As hemp becomes a more important crop, so too does research into pests and diseases impacting it.
It’s a hardy plant, but various diseases and hemp insect pests can negatively impact yields or kill plants altogether. One of the major threats to the crop is Fusarium head blight (FHB), caused by the Fusarium fungus. It can lead to the death of plant tissues in hemp seed heads and flowers.
Furthermore, Fusarium fungi can produce harmful mycotoxins that pose risks to human and animal health, and this is particularly concerning for producers in the animal feed market.
UK researchers associated with the University of Kentucky Martin-Gatton College of Agriculture, Food and Environment have been making some headway; identifying a significant risk factor. They found the species of Fusarium affecting hemp are the same as those triggering head blight in wheat, barley and other cereal crops.
“Our preliminary findings suggest that crop rotations involving hemp and wheat need to be reconsidered,” according to Nicole Gauthier, who is a hemp extension plant pathologist and Department of Plant Pathology extension professor. “The risk of Fusarium spreading between these crops could impact both yields and quality.”
Fusarium also presents a threat beyond the field.
“It’s looking like Fusarium can survive in stored hemp, impacting product quality even after harvest,” Professor Gauthier said. “This highlights the importance of careful post-harvest management.”
A 2020-2021 study led by Professor Gauthier that included over 300 samples from 17 field sites across Kentucky found an average of 39% of samples (from each field site) tested positive, ranging from 11% to 47% incidence.
One of the particularly challenging aspects of FHB revealed by the research is infections in hemp can occur months before visible symptoms develop, which often occurs after plants begin to flower. While this creates difficulties for detection, it also provides a window for intervention.
But there are no fungicides currently approved for use on hemp for FHB, and resistant cultivars have yet to be developed – addressing both of which are long-term goals of the research team.
The research is being carried out under the UK Hemp Research, Extension and Education program at Martin-Gatton CAFE.
