Evaluating the Response ro Fungicide in Different Tillage System

Trial Overview

  • Fungicide application to corn is a relatively common practice in Illinois.
  • Low commodity prices are calling the return on investment (ROI) for a fungicide application into question.
  • Different tillage systems may provide different environments that are more or less preferable to disease development.

Research Objective

  • This trial was established to evaluate the yield response to fungicide in different tillage systems.
Soil Type
Previous Crop
Tillage Type
Planting Date
Harvest Date
Potential Yield
Planting Rate
Monmouth, IL
Silt Loam
240 bu/acre
36,000 seeds/acre

Site Notes:

A large land block was divided into three different tillage zones:
          - Vertical Tillage
          - Strip Tillage
          - Conventional Tillage
Within each of the three tillage zones, two corn products were planted:
          - 108 Day RM SmartStax® RIB Complete® Corn Blend
          - 114 Day RM SmartStax® RIB Complete® Corn Blend
Each product had treatments consisting of an untreated check and an application of a foliar fungicide that contained strobilurin and triazole active ingredients (A.I.). There were two replications of all treatments. The fungicide was applied at the R1 growth stage.



Understanding the Results

Figure 1. Average yield response (bu/acre) for fungicide application to three tillage systems at Monmouth, Illinois (2017, 2 Replications).
  • Disease incidence was low; however, the disease symptoms that appeared were generally very late in the season and likely had little to no impact on yield.
  • No differences in symptomology were seen between the treated and untreated plots.
  • Because of these factors, no discernible differences or trends were observed in the final yield results (Figures 1 and 2).
  • Three factors are required for disease development: a pathogen, a susceptible host, and favorable environmental conditions.
  • In 2017, the cool, dry conditions in July and August likely held disease pressure to a minimum at the Monsanto Learning Center at Monmouth, IL. An example is the minimal number of gray leaf spot lesions found on corn leaves (Figure 3).

What Does This Mean for Your Farm

  • Various methods for preventing disease development in corn include planting resistant genetics, crop rotation, and good residue management practices.
  • A good scouting program is crucial to identify whether a disease is a problem in any given field.
  • If all three factors for disease development are present, a fungicide application may help protect yield potential.