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Soybean R3 Fungicide Trials

Key question: Are fungicides applied at R3 to soybean effective at increasing yield and reducing foliar disease?

Treatments: Strips with fungicide applied at R3 vs. strips with no fungicide application.
*Farmer’s choice of product used.

Fungicide trials information and results

  • Layout of the trial

    Each fungicide trial is custom designed to work within the individual farmer’s designated field using their own equipment to plant, spray, and harvest the treatment strips in their field.

    The farmer chooses the variety of soybean to be planted, the fungicide product and all other management decisions.

    Each field is laid out with a minimum of five fungicide sprayed strips and five strips not sprayed with fungicide. The width of the strips is based on the size of your spray equipment.

    In the example below, the green strips were sprayed with fungicide at R3. The blue points are where the field was scouted for foliar disease.

    In the example below, the green strips were sprayed with fungicide. The blue points are where the field was scouted for foliar disease.

    Fungicide trial map layout

    To document differences in disease between the treatment strips, scouting for foliar diseases was performed at several locations within each treatment strip prior to and approximately two weeks following the fungicide application at the R3 stage. In addition, aerial imagery was taken at each of the scouting points to visually document the differences.

    Scout images

  • Results summary (2018-2019)

    Soybean R3 Foliar Fungicide Trial locations

    2018 and 2019 fungicide trial locations

    2019 scouting school locations

    R3 Fungicide for Soybean: Location details

    2018 fungicide trial location details

    2019 fungicide trial location details

    In 2018, 8 of 11 locations completed and were used in the analysis. In 2019, key information is available for 10 of 11 locations at this time.

    R3 Fungicide for Soybean: Effect on yield

    Effect on yield

    How to interpret graph:

    • Green diamonds are the mean effect of fungicide treatment for each location; diamonds right of the center line indicate the mean effect at that location was positive.
    • Black (no R3 fungicide) and gold (R3 fungicide) symbols are strip yields for each location, as the difference from the location mean.
    • Credible interval is the expected yield effect of R3 Fungicide based on these 18 farms (95% to 5% probability).

    Key points:

    • Across these 18 farms, R3 fungicide increased yield.
    • The benefit was less than 2 bushes per acre.
    • There was more than a 50% chance of a one bushel/acre response.
    • Results by location suggested significant benefit a five of 18 locations.

    R3 Fungicide for Soybean: Effect on Septoria Disease Rating

    effect on septoria rating

    Key points:

    • 2018 and 2019 had low disease ratings.
    • Primary disease observed: Septoria
    • A benefit of R3 fungicide will reduce disease ratings pushing green diamonds to the left of the center line.
    • The benefit of R3 fungicide on disease ratings, across these 17 farms was, at best, small.

  • Summary reports

    2018 locations 2019 locations
    1. Ralls County (PDF) 1. Barton County (PDF)
    2. Barton County (PDF) 3. Greene County (PDF)
    3. Polk County (PDF) 4. Holt County (PDF)
    4. St. Clair County 5. Scott County (PDF)
    5. Nodaway County (PDF) 6. Lincoln County (PDF)
    6. Warren County (PDF) 9. St. Clair County (PDF)
    7. Scott County (PDF) 10. Buchanan County (PDF)
    8. Perry County 11. Perry County (PDF)
    9. Atchison County (PDF) 13. Mississippi County (PDF)
    10. Marion County (PDF) 14. Ralls County (PDF)
    11. Lincoln County (PDF)