Poster # 110

Dalitso Yabwalo ¹, Karl Glover ¹, Connie Tande ¹, Anna Hagemann ¹ and Madalyn Shires ¹
1. South Dakota State University, Brookings, SD
Corresponding Author: Dalitso Yabwalo, dalitso.yabwalo@sdstate.edu

Hagemann, Anna

anna.hagemann@jacks.sdstate.edu

Fusarium graminearum, a fungus that causes Fusarium head blight (FHB), affects both kernel quality and yield of wheat. In infected heads, the pathogen disrupts nutrient translocation to the kernels leading to poorly filled kernels which also accumulate mycotoxins. Deoxynivalenol (DON) is the most prevalent mycotoxin produced by F. graminearum. This study aimed to identify the optimal fungicide application strategy that maximizes wheat yield (bu/A) and kernel quality. The treatment structure included fungicides applied at (i) anthesis namely, Prosaro (6.5 fl oz/ac), Miravis Era (10.3. fl oz/ac), Miravis Ace (13.7 fl oz/ac), Prosaro Pro (10.3 fl oz/ac), and Sphaerex (7.3 fl oz/ac), (ii) two fungicides applied in sequence, with the first application done at anthesis followed by a second application at the completion of flowering, and (iii) fungicides applied at the completion of flowering (post Anthesis) namely; Prosaro Pro (10.3 fl oz/ac), Sphaerex (7.3 fl oz/ac), and Miravis Ace (13.7 fl oz/ac. A randomized complete block design with four blocks was used to allocate fungicides to experimental units. Inoculation was conducted with corn spawn at boot stage and ascospores 24h after anthesis fungicide application. Data were analyzed using the generalized linear model (proc glimmix) with appropriate link functionalities. The sequential application strategy was the most effective for FHB management with the lowest DON content, Fusarium damaged kernels (FDK), and FHB severity, although there were no statistically significant (p≤0.05) differences among treated plots. The sequential application strategy also produced 38% higher yield than the untreated and about 13% more than the anthesis and post anthesis applications. The sequential application of Miravis Ace (13.7 fl oz/ac) followed by Prosaro Pro (10.3 fl oz/ac) resulted in the lowest FHB related metrics (DON, FDK, and FHB severity). Positive Spearman associations (r=0.67, p<.0001) between FDK and DON, FHB severity and DON (r=0.53, p<.0001), were also observed. The results generated in this study suggest that applying fungicides at anthesis followed by a second application by the end of the flowering period is a superior strategy for managing FHB severity and maximizing yield, particularly under high disease pressure. ACKNOWLEDGEMENT AND DISCLAIMER This is based upon work supported by the USDA Agreement No 59-0206-0-115. This is a cooperative project with the U.S. Wheat & Barley Scab Initiative. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the view of the U.S. Department of Agriculture.

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