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Poster: Epidemiology: Cropping Systems/Sustainability


Effect of pre-anthesis rainfall patterns on fusarium head blight and deoxynivalenol in wheat: a multi-state study
W. BUCKER MORAES (1), K. F. Andersen (1), C. Cowger (2), R. Dill-Macky (3), L. V. Madden (1), P. Anderson Paul (1) (1) Department of Plant Pathology, The Ohio State University, U.S.A.; (2) Department of Plant Pathology, North Carolina State University, U.

Although there is often a correlation between visual symptoms of Fusarium head blight (FHB) and deoxynivalenol (DON) in wheat, under certain conditions, DON levels may be higher than one would expect based on visual symptoms. Between 2012 and 2015, field experiments were conducted at three locations (Minnesota, North Carolina, and Ohio), representing different wheat growing regions and market classes, to investigate the effects of intermittent rainfall during the 7-8-day pre-anthesis window on FHB and DON in wheat. Plots were inoculated with corn kernels colonized by Fusarium graminearum at jointing (Feekes GS 6). The experimental design was a randomized complete block with five pre-anthesis simulated rainfall treatments: 1) rainfall every day (Rain_1); 2) rainfall only on the first and last two days of the window (Rain_2); 3) rainfall only on the middle 3-4 days of the window (Rain_3); 4) rainfall every other day (Rain_4); and 5) check. Plots that received simulated rain had numerically higher mean FHB incidence (INC), index (IND), Fusarium damaged kernels (FDK), and DON than the check at all locations. Rain_1 consistently resulted in higher mean INC and IND than Rain_2, Rain_3 and Rain_4. However, Rain_2 and Rain_4 had comparable mean FDK and DON to Rain_1. Thus, dry-wet moisture cycles may be associated with disproportionately high DON for a given level of IND.