Effect of Environment on Fusarium Head Blight Intensity and Deoxynivalenol Content in Wheat Grains: Development of a Forecasting System

In Argentina, Fusarium head blight (FHB) is a serious fungal disease (caused by Fusarium graminearum) that affects wheat yield and grain quality because of mycotoxin (deoxynivalenol: DON) contamination. The sporadic nature of FHB epidemics is related to its strong weather dependence. Environment-controlled experiments were conducted in Castelar in 2006 and 2007 to study the effect of wetness duration and temperature on three visual estimates of FHB (incidence, severity and Fusarium index) and grain DON content, and to develop a meteorological-based forecasting system of the mycotoxin. Both Fusarium Index (incidence%*severity%/100) and severity were significantly related to wetness duration and temperature and strongly associated to DON content. Relationships between environmental factors and DON content were not significant. From the information generated by these environment-controlled experiments which used local F. graminearum isolates, it was possible to modify one of the current forecasting systems of Fusarium index as well as to predict DON content. The new forecasting system was satisfactorily validated with independent data, and using primary meteorological daily data from surface stations may estimate annual DON content in mature grains.