Multi-Year Results of Fungicide Applications on Specific Corn Products - DEKALB® - IOWA



Yield response of corn products to fungicide application at tasseling development stage (VT) was measured in replicated small plot research trials in Iowa across 2 years and 2 locations. Pictures were taken to show how some products resist disease development in the absence of fungicide application.


The objective of the experiment was to demonstrate the genetic propensity of certain corn products to resist disease pressure.

Location Previous Crop Planting Date Harvest Date
Victor, IA Soybean Normal for region Normal for region
Atlantic, IA Soybean Normal for region Normal for region

SITE NOTES: The trial consisted of 4-row 45-foot-long plots with 3 replications in two adjacent blocks (fungicide treatment and untreated) at each site-year. The center 2 rows were harvested for yield. Fungicide was applied at full labeled rate using a high clearance sprayer at VT.



Table 1. Positive Yield Response by Year and Site. NA – No data available. *No positive yield response. **DEKALB® Disease Shield™ Product. 1 – Northern Corn Leaf Blight; 2 – Gray Leaf Spot; 3 – Anthracnose Stalk Rot; 4 – Southern Rust


Figure 1. This photo indicates average disease pressure without fungicide at Victor, IA in 2017. Gray Leaf Spot and Southern Rust are the predominant diseases in this picture.


Figure 2. DKC63-60RIB Brand Blend with fungicide (left) and without fungicide (right) at Victor, IA in 2017.


Figure 3. DKC 64-34RIB Brand Blend with fungicide (left) and without fungicide (right) at Victor, IA in 2017.

  • Note the leaf disease severity of an average corn hybrid in Figure 1 compared with DKC63-60RIB Brand Blend and DKC64-34RIB Brand Blend in Figures 2 and 3 respectively.
  • Note that little observable difference in disease presence between plants treated with fungicide and those not treated with fungicide in these two products.


  • Corn product response to fungicide treatment can differ across years, so each season growers should evaluate whether to apply fungicides based upon the environment, disease incidence, and disease tolerance of products.
  • Select products with good disease ratings to help mitigate risk of diseases. These selections could include DEKALB® Disease Shield™ RIB Complete® corn blend products.

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