Corn Response to Fungicide Application Timing

January 17, 2022

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Corn Response to Fungicide Application Timing - 2021


  • Fungicides are often used to protect corn from disease and help producers reach higher yield potential, but there are multiple timings that the fungicide can be applied.

  • The goal of this trial was to look at the yield impact of one or multiple applications Delaro® Complete Fungicide on three corn products.


Location Gothenburg, NE
Soil Type Hord silt loam
Previous Crop Sorghum
Tillage Type Strip tillage

Planting Date 04/26/21
Harvest Date 11/04/21
Potential Yield (bu/acre) 280
Seeding Rate (seeds/acre) 36,000

Table 1. Trial treatments including corn products of varying relative maturity (RM), fungicide rates, and application timing.


  • The study was setup in a split-plot design with four replications. Fungicide treatments were the whole plot, and corn products were the sub-plot.

  • A base fertilizer application of 25 lb/acre nitrogen (N), 60 lb/acre phosphorus (P), 25 lb/acre sulfur (S), 0.25 lb/acre zinc (Zn) was applied with a strip-till application across all treatments on April 23, 2021.

  • A stream bar broadcast application of 100 lb/acre N was made on 5/12/2021.

  • An additional 60 lb/acreN was applied with 360 Yield Center Y-drops on 6/18/2021 at the V7 growth stage. Weed control consisted of a VE application of 5 oz/acre Corvus® herbicide , 2.0 pt/acre Harness® , 1 qt/acre Atrazine 4L, and 1 qt/acre Roundup® PowerMAX on 5/8/21 followed by a post-emerge application of 3.0 oz/acre Laudis® herbicide , 3 pt/acre Warrant® Herbicide , and 12 oz/acre DiFlexx® herbicide , and 1 qt/ac Roundup® PowerMAX on 6/15/2021. Weed control was excellent season long.

  • Corn was sprinkler irrigated with a total of 5.5 inches of irrigation applied during the growing season.

  • Dry conditions during the growing season led to little fungal disease development in the trial.

  • Plots were combine harvested. Grain moisture content, test weight, and total weight were determined. Statistical analysis for Fisher’s LSD was performed.


Figure 1. Average corn yields for three corn products as impacted by two fungicide rates and timings at the Bayer Water Utilization Learning Center, Gothenburg, NE (2021).

  • Yield was improved by both fungicide application timings over the untreated control even with the dry conditions and low disease pressure observed at the end of the growing season.
    • The VT application alone showed a 5.7 bu/acre advantage over the untreated control.
    • The V6+VT application had a 15 and 9.7 bu/acre advantage over the untreated control and VT application respectively.


  • The key benefit observed with Delaro® Complete Fungicide applications was an increase in corn yield for both application strategies.

  • Applying an early V6 application of Delaro® Complete Fungicide along with a VT application in sequence provided the highest yields in this study.

  • The yield improvement has been consistent across both the 2020 and 2021 growing seasons at the Bayer Water Utilization Learning Center in Gothenburg, NE.

  • Farmers should check with their local Bayer Crop Science seeds sales team member to discuss the right corn product and management plan for their fields.