FUNGICIDE APPLICATION AT HERBICIDE TIMING IN DRYLAND WINTER WHEAT
Agronomy & Pest Management
Aaron Esser
Extension Agronomist
Washington State University
RITZVILLE
Abstract
The application of fungicides with herbicide timing is a common practice for winter wheat (Triticum aestivum) farmers across eastern Washington for stripe rust and Strawbreaker foot rot (commonly called eyespot) control. They commonly cite ‘free ride’, ‘cheap insurance’, and ‘plant health’ as justification for this approach. However, this approach increases costs, potentially antagonizes grassy weed control, and research is needed on the impact fungicide application on soil health. Washington State University and USDA/ARS scientists devote resources into assessing and rating wheat cultivars for susceptibility to both these diseases, so growers can make more informed decisions about fungicide application. This data is widely available via print, web, and verbal communication. In 2020, an on-farm trial was established at the WSU Wilke Research and Extension Farm to examine the feasibility of fungicide application, and this study has been repeated each year through the 2024 crop (5 years and 7 site years). Plots are 200 ft long and 30 ft wide with 4 replications and a randomized complete block design. Three treatments were established: 1) 10 gal/ac water (check), 2) 14 oz/ac Quilt Xcel fungicide, and 3) 18 g/ac PiKSi dust (potassium silicate). Quilt Xcel has both stripe rust and Strawbreaker foot rot on its label at the 14 oz/ac application rate. Variety selection is very important and has varied from year to year. In 2020 and 2021 Resilience CL+ was grown, in 2022 and 2023 Piranha CL+ was grown, and in 2024 both Sockeye CL+ and Kraken AX were grown. There were no agronomic differences within all three treatments over the 5 years the study was completed despite multiple growing seasons and varieties planted. Winter wheat yielded 88.4 bu/acre over the duration of the study.
Authors: Aaron Esser
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Aaron Esser Extension Agronomist, , Washington, 99169-1894