In-Season Soybean Management


  • Foliar fungicides and insecticides are 2 commonly used in-season management tools for protecting yield in soybean. 
  • Nitrogen (N) fertilizer is seldom used in soybean production; however, given the high N requirement of the crop and increasing yields, N availability could limit production.


  • Determine whether in-season applications of foliar fungicide + insecticide or N fertilizer can consistently increase soybean yield.

Study Description

Plot Layout: Small plot experiments
Replicates: 16 per location
Locations: 5 locations over 2 years in IL
location map

In-Season Management Treatments:

  • Non-treated
  • Foliar fungicide + insecticide
  • N fertilizer (80 lbs N/acre)

Locations (By Year):  Princeton 2011 (P11), Champaign 2011 (C11), Mascoutah 2011 (M11), Princeton 2012 (P12) and Belleville 2012 (B12).

Foliar (Fol):  A foliar fungicide and insecticide were applied simultaneously at labeled rates during early pod development (R3).

Nitrogen (N):  80 lb N per acre as ESN (polymer coated urea) was surface applied at full flower (R2).



  • Yields were generally high at all locations; Princeton was the highest, averaging 85 and 72 bu/acre in 2012 and 2011, respectively.
  • Mascoutah, Belleville and Champaign all averaged 62 bu/acre.
  • Yield increases from foliar fungicide + insecticide or N treatments ranged from 0.8 to 3.7 bu/acre.
  • Yield increases with N fertilizer were significant at all 5 site-years (p < 0.10).
  • 2 of the 5 site-years had significant yield increases with foliar fungicide + insecticide.
  • 4 of the 5 site-years had a greater average yield response to N fertilizer than fungicide + insecticide.


yield increase chart

Soybean yield increase with foliar fungicide + insecticide (Fol) or N fertilizer at
5 IL site-years in 2011 and 2012. Asterisks indicate a significant (p < 0.10)
yield increase.

2012 data are based on average of all comparisons made in 5 locations through Nov. 21, 2012. Multi-year and multi-location is a better predictor of future performance. Do not use these or any other data from a limited number of trials as a significant factor in product selection. Product responses are variable and subject to a variety of environmental, disease and pest pressures. Individual results may vary.