K. D. Bondalapati, Plant Science Department, South Dakota State University, Brookings, US-SD 57007;
J. M. Stein, Plant Science Department, SDSU;
S. M. Neate, Department of Plant Pathology, North Dakota State University, Fargo, US-ND 58102;
S. H. Halley, North Dakota State University Langdon Research Extension Center, Langdon, US-ND 58249;
L. E. Osborne, Plant Science Department, SDSU; and
C. R. Hollingsworth, University of Minnesota Research and Outreach Center, Crookston, US-MN 56716
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Accepted for publication 1 November 2011.
The associations between Fusarium head blight (FHB), caused by Gibberella zeae, and deoxynivalenol (DON) accumulation in spring malting barley (Hordeum vulgare) and hourly weather conditions predictive of DON accumulation were examined using data from six growing seasons in the U.S. Northern Great Plains. Three commonly grown cultivars were planted throughout the region, and FHB disease and DON concentration were recorded. Nine predictor variables were calculated using hourly temperature and relative humidity during the 10 days preceding full head spike emergence. Simple logistic regression models were developed using these predictor variables based on a binary threshold for DON of 0.5 mg/kg. Four of the nine models had sensitivity greater than 80%, and specificity of these models ranged from 67 to 84% (n = 150). The most useful predictor was the joint effect of average hourly temperature and a weighted duration of uninterrupted hours (h) with relative humidity greater than or equal to 90%. The results of this study confirm that FHB incidence is significantly associated with DON accumulation in the grain and that weather conditions prior to full head emergence could be used to accurately predict the risk of economically significant DON accumulation for spring malting barley.
© 2012 The American Phytopathological Society