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Analyses of Yield and Economic Response from Foliar Fungicide and Insecticide Applications to Soybean in the North Central United States

    Affiliations
    Authors and Affiliations
    • Yuba R. Kandel
    • Daren S. Mueller , Department of Plant Pathology and Microbiology
    • Chad E. Hart , Department of Economics
    • Nathan R. C. Bestor , Department of Plant Pathology and Microbiology, Iowa State University, Ames 50011
    • Carl A. Bradley , Department of Plant Pathology, University of Kentucky, Princeton 42445
    • Keith A. Ames , Department of Crop Sciences, University of Illinois, Urbana 61801
    • Loren J. Giesler , Department of Plant Pathology, University of Nebraska-Lincoln 68508
    • Kiersten A. Wise , Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907

      Published Online:https://doi.org/10.1094/PHP-RS-16-0038

      Foliar disease and insect management on soybean (Glycine max L. Merrill) in the North Central region of the United States has been increasingly accomplished through foliar fungicide and insecticide application. Data from research trials conducted in Illinois, Indiana, Iowa, and Nebraska were compiled from 2008 to 2014 to determine the impact of fungicide, insecticide, and fungicide + insecticide applications on soybean yield and profitability. In each state, field experiments occurred each year in two to seven locations. All treatments were applied at the R3 growth stage. Disease and insect pressure were very low in all states and years. A foliar application of fungicide, insecticide, or the combination, increased yield in seven out of 14 total site-years (P < 0.10). Economic analysis using an average soybean price of $0.42 per kilogram and average application cost of $62 per hectare indicated that fungicide applications were only profitable in 14% of the trial site-years. Insecticide alone and fungicide + insecticide was profitable in 39% and 45% of site-years, respectively. Effect of fungicide class on yield was inconsistent. Our results indicate that although yield increases can occur with foliar fungicide and/or insecticide treatments, current market prices and application costs may limit profitability when disease and/or insect pressure is low.

      Accepted for publication 22 September 2016.