Effect of Seed Treatment on Soybean Appearance

"My soybeans are treated, what should I expect?"

Field Facts written by Pioneer Agronomy Sciences


Pioneer® brand soybean seed with fungicide and insecticide seed treatments applied by Pioneer Sales Professionals will also have a colorant added which is most often green in color. The general "treated appearance" of the seed may vary between varieties or even variety Lots, as the adherence of the product may be affected by dust on the seed or the oily finish of some soybean seeds.

Soybeans treated with a colorant may show more of the physical imperfections of the seed. The quality of the soybean seed is not different than that of untreated seed, but the colorant may magnify these normally "hidden" characteristics.

The general 'treated appearance' of soybean seed may vary between varieties or even within a variety.


Treated seed may require some planter adjustments in the field. It is not uncommon to see a reduced seed drop of 8-10% on treated seed versus untreated if no adjustments are made. Be prepared to make planter adjustments per the manufacturer’s recommendations. The addition of talc may also improve the plantability of the seed.

Agronomic Benefits

Treated soybean seed will provide many agronomic benefits regardless of planting date. However, treated seed should be prioritized for the following environments or situations:

  • Earliest planted fields
  • Poorly drained fields
  • Fields with a history of poor stand establishment
  • Treated soybean seed will provide many agronomic benefits regardless of planting date.

    Field Observations

    • Faster emergence
    • Increased stand establishment
    • Reduced feeding from bean leaf beetles when an IST is used
    • Faster crop canopy development
    • Suppression of soybean aphid when an IST is used

    Documenting the Benefits

    Because insects in untreated soybeans may continually re-infest IST treated soybeans in the adjacent rows of the side-by-side, we recommend that you plant comparisons of untreated and treated soybeans in "blocks" and not in "strips". When harvesting in the fall, harvest the comparison far enough apart to account for movement of insects from the untreated to the treated blocks. Usually a minimum of 80-100 feet is adequate.