UNDERSTANDING THE CHALLENGES OF FUSARIUM HEAD BLIGHT FORECASTING

Fusarium Head Blight (FHB) is one of the most important diseases of wheat and barley in U. S. During severe epidemics FHB has resulted in billions of dollars in losses and has renewed interest in developing integrated disease management strategies for this disease. Plant disease management strategies recommend the use of moderately resistant cultivars; reduction in corn residue in the field; and the use of protective fungicides, when needed. Forecasting systems can help wheat producers evaluate the risk of disease and the need for fungicide applications. In this dissertation, winter and spring wheat FHB forecasting models were developed to help growers evaluate the risk of disease epidemics in their area. Both models used weather information from seven days prior to anthesis. In additions to this weather information, the spring wheat model successfully incorporated cultivar resistance as a risk assessment factor, and the winter wheat model accounted for the presence of corn residue. Both models had accuracies above 70%. Error analysis was conducted and a decision rule was incorporated to the spring wheat model to account for drought and significantly wet periods 21 days prior to anthesis.Challenges addressed in this research included the relationship between weather station scale level indicators and large scale FHB epidemics, methods of reducing variability introduced from cropping practices, methods for evaluating modeling approach and model selection and ranking.