Impact of Fungicide on Soybean Yield

Trial Objective

  • This study was conducted to evaluate if soybean products respond differently to a fungicide application and to determine the impact of a fungicide application on soybean yield, regardless of the level of disease pressure.

Research Site Details

  • The study was set up as a split plot with three replications. Fungicide was the whole plot and soybean product was the subplot.
  • Eighteen soybean products were evaluated ranging in maturity from a 2.0 to 3.5.
  • Delaro® 325 SC fungicide was applied at 10 fl oz/acre at the R3 growth stage.
  • Plots were sprinkler irrigated and weeds were controlled as needed.
  • Some soybean diseases (septoria brown spot, phomopsis pod and stem blight, and anthracnose) were observed at low levels but no soybean disease was prevalent at an economic threshold.

Understanding the Results

  • There was no significant interaction between soybean product and fungicide application even though there were some large differences in yield between the treated and untreated yields for a few products as seen in Table 1.  However, there was an overall significant benefit for the application of a fungicide as reported in Figure  1.


  • The fungicide application provided a positive $2.95 return per acre.
  • Test weight and harvest moisture were unaffected by the fungicide application.
  • For some soybean products, a noticeable difference was observed with more late-season growth from green stems with a fungicide compared to no fungicide (Figure 2).
  • Soybean product did impact yields significantly. Producers should work with their local seed sales team to identify how their branded soybean product performed in this study as detailed in Table 1.



What Does This Mean for Your Farm?

• A fungicide application may provide increased value even in years when soybean diseases are prevalent at low to moderate levels.

This browser is no longer supported. Please switch to a supported browser: Chrome, Edge, Firefox, Safari.