Detection of Fusarium Bud Blight in Kentucky Hemp Signals Emerging Disease Potential and Mycotoxin Exposure Risks

Detection of Fusarium Bud Blight in Kentucky Hemp Signals Emerging Disease Potential and Mycotoxin Exposure Risks By Mostafa Rahnama Since hemp was reintroduced in the U.S. under the 2014 Farm Bill, acreage has increased dramatically with a peak in 2019 at about 100,000 acres in the southeastern U.S. and over 500,000 acres in 47 states across the U.S. Hemp is susceptible to a wide range of diseases, including leaf spots, root rots, and head & flower molds. In 2019 and 2020, Fusarium bud and flower blight (FBB) was confirmed in Kentucky, as well as in North Carolina, New York, and Tennessee. In 2019, two cases of FBB were submitted to the diagnostic lab, and in 2020, three additional cases were confirmed. Travel limitations (Covid-19) prevented a thorough field survey by university specialists and agents, but in October 2020, N. Gauthier conducted an analysis of 14 hemp sites in which FBB was confirmed in four of them. Fusarium graminearum and other bud & head blight Fusarium spp. are common pathogens of cereals, grains, and grasses, particularly monocots. The pathogen is ubiquitous with a wide host range, but inoculum levels can be high in monocultured field production systems. Fusarium graminearum is primarily a flower pathogen; it infects flowers and accessory tissues, often moving to contaminate seeds. The fungus produces harmful trichothecene mycotoxins including deoxynivalenol (DON), nivalenol (NIV) and zearalenone (ZEA). Objectives of this project are to 1) Sample stored hemp from the 2020 growing season, accurately identify Fusarium graminearum, and confirm mycotoxin potential and 2) Develop educational materials for growers, educate on scouting and methods for sampling and testing their 2021 crops.