Avoid Post-harvest and Storage Molds: Fusarium Bud Blight and Head Blight Contamination in Stored Hemp

PRINCETON, KENTUCKY

   Fusarium head blight (FHB, also called scab in wheat and Gibberella ear rot in corn) is a serious disease of cereals and corn around the world. The disease also affects other cereal grains and grasses. Losses result from combinations of direct yield impacts caused by blighting and reduction in crop value caused by mycotoxin contamination. Fusarium bud blight and head blight on hemp (Figure 1) has been confirmed on cultivars grown for grain and fiber, as well as for floral tissue (cannabinoid production). The disease is an emerging concern in hemp production across the eastern U.S. and may increase in importance as the hemp market expands in the Great Plains, Midwest, and other regions of the U.S.

 Figure 1:Symptoms of Fusarium bud blight and head blight on hemp (Photo: Nicole Gauthier, UK)

   Management

   Resistant cultivars are currently not available; however, cultivars with longer internodes between individual buds may allow for better air circulation and decrease humidity within the flower/seed heads. Increased plant and row spacing improves air circulation and can reduce canopy humidity.  No conventional fungicides are labeled for control of Fusarium on hemp at this time. Management of budworms may reduce wounds and consequently reduce infections by Fusariumspp. There is no research available on the role of cereals or corn in the infection cycle of Fusarium on hemp, but it is likely that inoculum buildup can occur when hemp is rotated with other crops that are susceptible to the disease or when grassy weeds are not controlled. Management information will be updated as more information is available.  Research is ongoing.

• Avoid storing infected plant material; keep “suspicious” materials away from asymptomatic (healthy) materials. 
• Monitor relative humidity in storage facilities, coolers, and containers. 
• Check moisture regularly, particularly as temperature fluctuation can cause moisture migration. 
• Maintain good air circulation to reduce moisture and lower humidity.  Relative humidity should remain below 70% to reduce fungal growth and spread.

   Additional Resources

• Disease Alert Fusarium Bud Blight and Head Blight Contamination in Stored Hemp: Avoid Postharvest and Storage Molds  ∆