An Alternative to Optimize the Use of Fungicides to Control Fusarium Head Blight on Wheat

Abstract

Fusarium head blight (FHB) is one of the most important wheat diseases in Uruguay. Preventative fungicide sprays are the most common tool in FHB control. However, the timing of fungicide spray is still a bottleneck of this technology. The objective of this study was to evaluate the use of an empiric model suggested by Moschini and Fortugno to predict the occurrence of weather conditions conducive to the disease. The experiments were conducted during 2003-2006 with a diverse combination of cultivars and sowing dates. Three treatments were tested: i) No fungicide applied (T0), ii) fungicide sprayed at the beginning of flowering stage (T1), iii) fungicide sprayed when infection periods were predicted (T2). Prevalent weather conditions during the studied period were not conducive for severe FHB outbreaks. Joint analysis of the 50 experiments indicates significant effect of the treatment and the number of critical periods occurred over the susceptible stages on the incidence, severity and FHB index. These results indicate that at least two infection periods are needed for disease outbreak to occur. On the other hand, the use of the suggested model allowed to avoid unnecessary fungicide spraying (similar FHB index between T0 and T1) on 25% of the tested situations. This study contributes to the sustainable management of wheat production in Uruguay by more efficient use of chemical resources, minimizing their economical and ecological impact.