Evaluation of Application Timing of Miravis Ace for Control of Fusarium Head Blight in Wheat

Abstract

Fusarium head blight (FHB) is a serious disease of wheat and barley that not only lowers yield but also contaminates the grain with associated mycotoxins such as deoxynivalenol (DON). Chemical control options for FHB and DON include application of triazole fungicides at the anthesis or flowering stage. This presents practical challenges for growers in managing FHB, as the appropriate timing window typically lasts only 3 to 4 days. If this small window is missed, due to weather conditions or technical problems, fungicide application is less effective in controlling FHB and DON. The present work was conducted over 2 years (2019 and 2020) to test the efficacy of a new fungicide (pydiflumetofen + propiconazole) from Syngenta labeled as Miravis Ace in controlling FHB and DON content at 50% head emergence (Feekes 10.3), anthesis (Feekes 10.5.1), and end of flowering (Feekes 10.5.3) stages. Prosaro 421 SC, a standard FHB control triazole fungicide, was used at all three stages for comparison with the test fungicide. Miravis Ace application at 50% head emergence provided significant control over the nontreated check for FHB incidence (2020), FHB severity (2019), and DON content (2019) with control efficacies as high as 51, 69, and 52%, respectively. However, mean control percentages relative to the check were highest with Miravis Ace at anthesis in both 2019 and 2020 for all the FHB parameters. In conclusion, 50% head emergence provides statistically significant control on FHB and DON, but anthesis was the most effective application stage for Miravis Ace.