Fungicide and Planting Date in Soybean


  • Early planting may help maximize soybean yield potential when soil and weather conditions are suitable for seedbed preparation and seed germination.

  • In many cases, the application of a foliar fungicide can protect plant health and help maintain yield potential. 

  • The Monmouth Learning Center has been conducting trials for the past two years to evaluate the effects of planting date and an application of Delaro® 325 SC foliar fungicide on soybean yield potential.



LocationMonmouth, ILPlanting Date


4/24/19, 6/3/19


4/25/18, 5/18/18

Soil TypeSilt loamHarvest Date10/15/19 10/17/18
Previous CropCorn Potential Yield (bu/acre)  70   70
Tillage TypeConventionalSeeding Rate (seeds/acre)130K130K
  • A 3.6 MG Roundup Ready 2 Xtend® soybean product was planted on two dates each year of this experiment as indicated in chart above un planting date(s). 

  • Both plantings consisted of two treatments:

    • 8 oz/acre of Delaro® 325 SC fungicide applied at R3
    • An untreated check
  • There were two replications of each treatment.

  • Plots were harvested and adjusted to 13% moisture.

  • Disease incidence was very low in the plots in 2019.  A prolonged dry period from late June through early August may have been a major factor.



  • In 2019, the late-planted plots yielded higher than the early-planted plots, which is not typical of the planting date trials conducted at the Learning Center. The early-planted plots may have been affected by the prolonged cold, wet conditions at the beginning of the 2019 growing season.

  • Early plantings tended to benefit much more from the fungicide application.


  • In Learning Center trials, over the majority of years, early planted soybean tends to out-perform later planted soybean.

  • When planting early, it is important that soil and weather conditions are suitable for seedbed preparation and seed germination.

  • Scouting regularly is always the best way to determine if a fungicide application will be beneficial.

  • The benefit of a fungicide application will vary from year to year and individual fungicide application results may vary based on disease presence as well as weather and soil conditions. Consult your local Field Sales Representative or Technical Agronomist for recommendations. 



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