The Southeastern U.S. Fusarium Head Blight Epidemic of 2003

Abstract

Fusarium head blight (FHB) caused unprecedented losses to southeastern U.S. wheat producers and millers in 2003. The epidemic was documented afterward through interviews with 120 researchers, extension agents, millers, and growers. Sixty-two counties in five states were assigned an FHB impact score of 1 to 4, and 2003 yield and weather data were obtained for those counties. The relationships of yield and pre- and post-flowering weather variables to impact score were evaluated using regression and correlation analyses. Yield as a percentage of the 10-year average was negatively correlated with FHB impact (r = -0.588, P < 0.0001). FHB impact was positively correlated with hours of post-flowering rainfall (r = 0.465, 0.590, and 0.619 for 10, 20, and 30 days post-flowering, respectively; P = 0.0001), but not correlated with hours of pre-flowering rainfall (P = 0.99). While this was not a controlled study, the results suggest that pre-flowering weather may have played a less significant role than post-flowering weather, and was unlikely to have been a good predictor of FHB severity in the southeast in 2003. Using 10-year average production data, premilling economic losses were estimated for 40 counties in Maryland, Virginia, and North Carolina at over $13.6 million. Wheat production in those counties comprised just 71.7%, 45.8%, and 48.0% of the statewide totals, respectively; thus, actual 2003 FHB-related losses to growers in those states were probably much higher. Additionally, mills in the region suffered losses of several million dollars in 2003 due to increased shipping, testing, and handling costs brought on by FHB. Accepted for publication 26 September 2005. Published 26 October 2005.