Managing fusarium head blight in winter barley with cultivar resistance and fungicide

Authors: Cowger, Christina; ARELLANO, CONSUELO - North Carolina State University; Marshall, David; FITZGERALD, JOSHUA - Virginia Polytechnic Institution & State University

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/6/2019
Publication Date: 2/16/2019
Citation: Cowger, C., Arellano, C., Marshall, D.S., Fitzgerald, J. 2019. Managing fusarium head blight in winter barley with cultivar resistance and fungicide. Plant Disease. https://doi.org/10.1094/PDIS-09-18-1582-RE.
DOI: https://doi.org/10.1094/PDIS-09-18-1582-RE

Interpretive Summary: While there has been research on managing FHB in spring barley, little has been published on cultivar resistance and optimal fungicide timing for FHB management in winter barley. A three-year (2015-2017) field experiment was conducted to help winter barley producers select FHB-resistant varieties, judge the potential benefit from a fungicide, and choose the optimal timing for fungicide application. The split-plot experiment took place in a misted, inoculated nursery in Raleigh, North Carolina, using main plots of four winter barley cultivars (Atlantic, Endeavor, Nomini, and Thoroughbred). Three fungicide treatments were applied to sub-plots: prothioconazole + tebuconazole (Prosaro) when 100% of spikes had just emerged, the same fungicide six days later, or no fungicide. Neither visual disease symptoms nor deoxynivalenol (DON) in harvested grain gave any reason to prefer one of the fungicide timings over the other. Across the three years, DON ranked the cultivars Endeavor < Nomini = Thoroughbred < Atlantic. Combining the moderate resistance of Endeavor with a fungicide application, averaging the two timings, resulted in a 75% DON reduction compared to unsprayed Atlantic. Taken together, our results indicate that growers concerned about minimizing DON in malting barley should both plant moderately resistant barley varieties and apply fungicide if there is scab risk. During the same period, 16 commercial winter barley cultivars were tested in from three to seven Virginia and North Carolina environments each, and the DON results were compared after standardization across environments. The winter two-row malting barley cultivars Endeavor and Calypso displayed superior and robust DON resistance across environments.

Technical Abstract: While there has been research on managing FHB in spring barley, little has been published on cultivar resistance and optimal fungicide timing for FHB management in winter barley. A three-year (2015-2017) field experiment was conducted to help winter barley producers select FHB-resistant varieties, judge the potential benefit from a fungicide, and choose the optimal timing for fungicide application. The split-plot experiment took place in a misted, inoculated nursery in Raleigh, North Carolina, using main plots of four winter barley cultivars (Atlantic, Endeavor, Nomini, and Thoroughbred). Three fungicide treatments were applied to sub-plots: prothioconazole + tebuconazole at 100% spike emergence, the same fungicide six days later, or no fungicide. Neither visual disease symptoms nor deoxynivalenol (DON) in harvested grain gave any reason to prefer one of the fungicide timings over the other. Across the three years, DON ranked the cultivars Endeavor < Nomini = Thoroughbred < Atlantic. Combining the moderate resistance of Endeavor with a fungicide application, averaging the two timings, resulted in a 75% DON reduction compared to unsprayed Atlantic. Taken together, our results indicate that growers concerned about minimizing DON in malting barley should both plant moderately resistant barley varieties and apply fungicide if there is scab risk. During the same period, 16 commercial winter barley cultivars were tested in from three to seven Virginia and North Carolina environments each, and the DON results were compared after standardization across environments. The winter two-row malting barley cultivars Endeavor and Calypso displayed superior and robust DON resistance across environments.