Low Benefits from Fungicide Use on Hard Red Wheat in Low-Disease Environments

Abstract

The use of fungicides on hard red wheat in the northern Great Plains increased in part owing to inexpensive fungicide options and several years of foliar disease epidemics. In some instances, fungicides are used in the absence of disease, prompting questions on the perceived value of these applications. This study analyzed yield data from 46 fungicide trials conducted in low-disease environments from 2007 to 2014 on hard red spring wheat and hard red winter wheat. Data were sorted and organized to determine yield response attributed to fungicide application timing (Feekes 2–3 or Feekes 9) and fungicide mode of action. Fungicide modes of action included quinone outside inhibitors (QoIs), demethylation inhibitors (DMIs), succinate dehydrogenase inhibitors (SDHIs), and blends (mixtures of QoI, DMI, or SDHI). A meta-analysis indicated a significant yield response of 101.6 kg/ha for a Feekes 9 application and 69.3 kg/ha for applications that used a QoI. Economic analyses indicated that when a midpoint value for both wheat price and application cost were used, less than one-third of the trials had a profitable net return when a Feekes 9 application was used. The infrequent positive yield responses associated with foliar fungicides in low-disease environments should prompt growers to evaluate disease risk prior to making an application for foliar diseases.