Foliar Fungicide Effects on Disease Severity, Yield, and Agronomic Characteristics of Modern Winter Wheat Genotypes

Abstract

Core Ideas Foliar fungicide application at the flag leaf stage (Zadoks 39) improved grain yield and grain protein content.One time application of foliar fungicide resulted in economic returns up to US$204 ha–1.Grain volume weight, grain size, leaf area index, and leaf greenness were improved from foliar fungicide application at the flag leaf stage. Foliar diseases limit winter wheat (Triticum aestivum L.) production in the Great Plains of the United States. Farmers often use foliar fungicide application to counter yield loss. Two‐year field experiments were conducted at two locations in Nebraska to investigate the effects of foliar fungicide (Prosaro 421 SC [Bayer Crop Science, Leverkusen, Germany]: prothioconazole + tebuconazole) at the flag leaf stage on yield and agronomic characteristics of winter wheat. Foliar fungicide application increased grain yield, grain protein content, seed weight, grain volume weight, leaf greenness, and leaf area by up to 42, 1, 16, 6, 48, and 35%, respectively. Foliar fungicide at the flag leaf stage in the spring reduced disease severity (up to 84%), area under disease progress curve (up to 87%), and agronomic characteristics that resulted in economic returns of up to US$204 ha−1 excluding the premium farmers get from increased protein. Susceptible to moderately susceptible genotypes were more responsive to foliar fungicide on controlling disease severity and improving grain yield compared to moderately resistant to resistant genotype when disease pressure was high. This study showed that the economic benefit for all genotypes obtained from improved grain yield, grain volume weight, grain protein content, and grain size due to one‐time application of foliar fungicide at the flag leaf stage in winter wheat could have significant benefit to the farmer’s economy and wheat industry.