Evaluation of fungicide timing and preventative application on the control of Fusarium head blight and resulting yield

Abstract

The effect of spray application timings of two fungicides on Fusarium head blight (FHB) severity and grain yield was investigated in an inoculated field experiment. The fungicides Prosaro (tebuconazole + prothioconazole) or Folicur (tebuconazole) were applied 7 days pre-, at GS61, or 7 days post-artificial inoculation with Fusarium graminearum (Fg) at 25 % flowering (GS61). Prosaro was also examined at an additional timing of 3 days post-GS61. In addition, the efficacy of a preventative application of tebuconazole + prothioconazole at GS61 was investigated with inoculation at GS61 or delayed 5 days post-, 10 days post- or 15 days post-GS61. Tebuconazole + prothioconazole was generally more effective than tebuconazole alone at all application times. Application 7 days pre- and 7 days post-inoculation at GS61 reduced efficacy and yield benefits of both fungicides, but the losses were greater with tebuconazole alone. There was no significant reduction in efficacy when tebuconazole + prothioconazole was applied 3 days post-inoculation at GS61. A preventative application of tebuconazole + prothioconazole at GS61 provided good disease control and yield benefits irrespective of the timing of inoculation with Fg and appears to be a viable management strategy in situations of higher FHB risk.