Year of Publication

2021

Degree Name

Master of Science (MS)

Document Type

Master's Thesis

College

Agriculture, Food and Environment

Department/School/Program

Plant Pathology

First Advisor

Dr. Carl A. Bradley

Second Advisor

Dr. Lisa J. Vaillancourt

Abstract

Disease management in winter wheat can be improved by a properly implemented foliar fungicide program. The fungicide, application time, and application system should be selected based on the host, pathogens present, risk of fungicide resistance, and time of disease onset. These factors vary among environments and require region-specific research to determine appropriate practices. Trials were conducted to evaluate different aspects of fungicide applications for managing Fusarium head blight (FHB), caused by Fusarium graminearum, and the Septoria tritici leaf blotch complex, caused by Zymoseptoria tritici and Parastagonospora nodorum. A survey of P. nodorum isolates from Kentucky and Illinois and Z. tritici isolates from Kentucky showed that both pathogen populations included strains that were resistant to quinone outside inhibitor (QoI) fungicides. Trials were conducted to determine the optimal fungicide application time to manage the Septoria leaf blotch complex, and whether disease management programs benefited from adding a foliar fungicide. The effect that sprayer speed, nozzle type, and configuration had on coverage of wheat heads and FHB management was evaluated. Applying alternative fungicide chemistries to the QoI class at Feekes 9 along with an application at Feekes 10.51 made with an appropriate nozzle and application speed will provide a more effective fungicide program for winter wheat in Kentucky.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2021.420

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