An Evaluation of Single and Two Sequential Fungicide Applications During Flowering for Fusarium Head Blight Management in Winter Wheat in Kansas

Fusarium head blight (FHB), caused primarily by Fusarium graminearum Schwabe, remains a devastating disease of wheat. In this study, experiments were conducted across six location-years to evaluate the efficacy of sequential fungicide applications during the flowering period for FHB control, yield, deoxynivalenol (DON) reduction, and profitability in hard red winter wheat. The sequential treatments consisted of an application of Miravis Ace (propiconazole + pydiflumetofen) at Feekes 10.5.1 followed 4 days later by an application of either Prosaro Pro (prothioconazole + fluopyram + tebuconazole), Sphaerex (prothioconazole + metconazole), or TebuStar (tebuconazole). The sequential treatments were compared with single applications of Prosaro 421 SC (prothioconazole + tebuconazole), Sphaerex, Prosaro Pro, and Miravis Ace at Feekes 10.5.1. A covariance analysis was used to evaluate the influence of the FHB index (%) in the nontreated check on yield, DON, and net profit provided by the fungicide treatments. When the FHB index was low (10%), there were no significant yield or DON improvements. At higher FHB index levels of 30 and 40%, all fungicide treatments resulted in improved DON and improved yield relative to the nontreated check. Treatments including an application of Miravis Ace resulted in higher net profit and yields compared with the other treatments evaluated. The sequential fungicide application programs did not result in a significant yield benefit over a single application of Miravis Ace alone at any FHB index level. The results of this study underscore the importance of a single, well-timed application of Miravis Ace for FHB management in Kansas.