How to Navigate Foliar Fungicide Use in a Tight Soybean Market
With soybean prices under pressure and input costs climbing, foliar fungicide applications-typically costing $30 to $40 per acre-face increased scrutiny. Farmers aiming for optimal return on investment (ROI) must weigh disease risk, crop stage, and application timing with precision. Agronomists and Extension experts recommend aligning fungicide strategy with yield potential and environmental risk factors.
University Extension data confirms product plus application costs range from $30 to $40 per acre, pushing growers to consider yield thresholds. According to Penn State Extension, in the absence of strong disease pressure, these costs may not be recoverable. Farmdocdaily stresses that even when costs are known, two major uncertainties remain:
The yield response from fungicide use.
The additional drying costs from increased grain moisture levels due to fungicide application.
Growth Stage is EverythingTo time applications correctly, growers must identify when 50% of soybean plants have reached key developmental stages, per Iowa State University Extension. Most agronomists, including Matt Duesterhaus from Crop-Tech Consulting, target the R2 to R4 stages for fungicide-also the window when farmers often apply insecticides and foliar nutrients. These stages in late July mark peak pod development, a critical phase for maximizing yield potential.
"These pod development stages are about finalizing the potential for soybean yields," Duesterhaus explains. Protecting flowers and early pods is essential, as weather and pest pressure can reverse yield gains quickly.
| $3.50 | 11.40 | 7.10 |
| $4.25 | 9.70 | 5.90 |
| $5.15 | 7.80 | 4.90 |
| $6.05 | 6.60 | 4.10 |
| $6.95 | 5.80 | 3.60 |
Soybeans - Bushels Needed per Acre to Cover Fungicide Cost
| $8.50 | 4.70 | 2.90 |
| $9.75 | 4.10 | 2.60 |
| $11.00 | 3.60 | 2.30 |
| $12.25 | 3.30 | 2.00 |
| $13.50 | 3.00 | 1.90 |
White Mold Requires a Different ApproachWhen dealing with white mold, Michigan State University Extension recommends fungicide applications as early as R1 (when 50% of plants have one open flower). Mike Staton, an Extension specialist, also suggests a second application 10 days later if cool, humid weather persists.
New tools like Sporecaster, a mobile app developed by the University of Wisconsin, offer real-time recommendations on whether fungicides should be applied for white mold. Additionally, the Crop Protection Network has released updated 2025 Foliar Fungicide Efficacy Ratings, offering state-of-the-art product guidance.
Key Takeaways for 2025 PlanningFarmers in the Midwest and beyond should consider:
Aligning applications with R2-R4 stages for general fungicide use.
Applying at R1 and R1+10 days for white mold-prone fields.
Factoring in yield potential and disease pressure before investing in $30-$40/acre inputs.
Using tech tools like Sporecaster and consulting university extension resources.
Amid tighter margins, every fungicide pass must be data-driven, targeted, and justified by agronomic risk and economic return.