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Risk Assessment Models for Wheat Fusarium Head Blight Epidemics Based on Within-Season Weather Data

April 2003 , Volume 93 , Number  4
Pages  428 - 435

E. D. De Wolf , L. V. Madden , and P. E. Lipps

First author: Department of Plant Pathology, The Pennsylvania State University, Buckhout Laboratory, University Park 16802; and second and third authors: Department of Plant Pathology, The Ohio State University/OARDC, 1680 Madison Ave., Wooster 44691

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Accepted for publication 12 November 2002.

Logistic regression models for wheat Fusarium head blight were developed using information collected at 50 location-years, including four states, representing three different U.S. wheat-production regions. Non-parametric correlation analysis and stepwise logistic regression analysis identified combinations of temperature, relative humidity, and rainfall or durations of specified weather conditions, for 7 days prior to anthesis, and 10 days beginning at crop anthesis, as potential predictor variables. Prediction accuracy of developed logistic regression models ranged from 62 to 85%. Models suitable for application as a disease warning system were identified based on model prediction accuracy, sensitivity, specificity, and availability of weather variables at crop anthesis. Four of the identified models correctly classified 84% of the 50 location-years. A fifth model that used only pre-anthesis weather conditions correctly classified 70% of the location-years. The most useful predictor variables were the duration (h) of precipitation 7 days prior to anthesis, duration (h) that temperature was between 15 and 30°C 7 days prior to anthesis, and the duration (h) that temperature was between 15 and 30°C and relative humidity was greater than or equal to 90%. When model performance was evaluated with an independent validation set (n = 9), prediction accuracy was only 6% lower than the accuracy for the original data sets. These results indicate that narrow time periods around crop anthesis can be used to predict Fusarium head blight epidemics.

Additional keywords: disease forecasting, Fusarium graminearium , Gibberella zeae , head scab.

© 2003 The American Phytopathological Society