Poster # 104

Joseph Chonza¹, Isaack Kikway¹, Jorge Valle¹, and Pierce A. Paul¹
1. The Ohio State University, CFAES Wooster Campus, Wooster, OH 44691
Corresponding Author: PH: 330.263.3842; Email: paul.661@osu.edu

Chonza, Joseph

chonza.1@buckeyemail.osu.edu

Fusarium head blight (FHB), caused by the fungus Fusarium graminearum, reduces wheat yield and leads to grain contamination with mycotoxins, including deoxynivalenol (DON), which poses health risks for humans and animals. Under favorable weather conditions, a single fungicide application at anthesis may not be sufficient to reduce FHB and DON. In this study we continue and expand on ongoing research to evaluate the efficacy of double/sequential fungicide application programs by investigating the additivity of an anthesis application of Miravis® Ace followed by a post-anthesis application of Prosaro® for FHB and DON management. To accomplish this objective, separate plots of a susceptible wheat cultivar were treated either with Miravis Ace at early anthesis (MIR_A), Prosaro at 4 days after anthesis (PRO_4), Miravis Ace at early anthesis followed by Prosaro 4 days later (MIR_PRO), or left untreated. Trials were conducted in 2018, 2019, 2020 and 2021, with treatments arranged in a randomized complete block design with four replications. FHB index (IND) was rated at Feekes 11.2, and grain samples were collected at harvest and assayed for DON. The tested fungicide treatments resulted in significantly lower mean IND and DON than the non-treated check. In all cases, means were significantly lower for MIR_PRO than MIR_A or PRO_4, and significantly lower for MIR_A than PRO_4 for both IND and DON in three of the four years. The sequential application of Miravis Ace at anthesis followed by Prosaro 4 days after resulted in greater percent control of FHB index and DON than either treatment alone. Observed percent control (CO) values for MIR_PRO were comparable to the expected percent control (CE) values under the assumption of additivity in three of the four years (2018, 2019 and 2021). For IND, CO and CE were 0.96 and 0.95 in 2018, 0.92 and 0.95 in 2019 and 0.94 and 0.96 in 2021, whereas for DON, CO and CE values were both 0.85 in 2018, 0.88 and 0.84 in 2019 and 0.89 and 0.93 in 2021. Based on the principle of treatment independence, the combination of an anthesis application of Miravis Ace followed by a post-anthesis application of Prosaro was additive in terms of percent control. Further analyses will be conducted to evaluate this additive effect under a range of bassline FHB and DON levels in different wheat market classes.

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