Corn Fungicide Guide

Efficacy ratings, real pricing, and ROI analysis for 26 corn fungicide products. Based on 867 university field trials and 9,196 yield records.

What This Is

This guide compiles efficacy ratings, pricing data, and decision-making frameworks for corn fungicide products available in the U.S. market. It is not opinion or AI-generated content — it is a structured presentation of data from university field trials and published research.

Efficacy ratings come from the Crop Protection Network 2025 annual publication, which aggregates results from university researchers across the Corn Belt. Ratings reflect multi-year, multi-location trial performance against each disease.

Pricing data is sourced from three ag input suppliers (AgChem, FBN, Farmerceag) at actual purchase prices. Prices vary by geography, volume, and timing — use these as reference points, not quotes.

Yield response data draws from 867 trials across 6 universities spanning 2008-2025, with 9,196 individual performance records. You can explore the raw data in our Trial Data Browser.

Fungicide Efficacy Ratings

Ratings from the Crop Protection Network 2025 based on multi-year university trial data. Click column headers to sort. Use the filter to focus on a specific disease.

Excellent Very Good Good Fair Poor Untested / Not Listed

Source: Crop Protection Network 2025. Ratings reflect multi-year, multi-location field trial performance.

Pricing Comparison

Real purchase prices from three ag input suppliers. Some products have multiple generics at different price points. Click column headers to sort. A dash means no price available from that supplier.

Product Rate (fl oz) Acres/Gal AgChem ($/gal) FBN ($/gal) Farmerceag ($/gal) Best $/Acre

Prices as of early 2025. Actual pricing varies by geography, volume, and timing. Use as reference only.

Mode of Action & FRAC Groups

Understanding mode of action (MOA) is critical for resistance management. Corn fungicides fall into three main FRAC groups, often sold as premixes combining two or three.

FRAC Group 3 — DMI (Triazoles)

Resistance Risk: Low-Medium

Systemic, locally absorbed. Strong on gray leaf spot and eyespot. Examples: propiconazole (Tilt), prothioconazole (Proline), flutriafol (Xyway), mefentrifluconazole.

FRAC Group 7 — SDHI

Resistance Risk: Medium-High

Inhibit succinate dehydrogenase. Strong on gray leaf spot and southern rust. Examples: benzovindiflupyr (Trivapro), fluxapyroxad (Priaxor), pydiflumetofen (Miravis Neo), bixafen (Lucento).

FRAC Group 11 — QoI (Strobilurins)

Resistance Risk: High

Broad-spectrum, excellent on common rust and eyespot. Risk of resistance with repeated single-site use. Examples: azoxystrobin (Quadris), pyraclostrobin (Headline), picoxystrobin (Aproach), trifloxystrobin.

Multi-MOA Premixes (2-3 Groups)

Resistance Risk: Lower (built-in rotation)

Combining multiple FRAC groups in one product reduces resistance risk and broadens spectrum. Most premium products are premixes: Miravis Neo (7+11+3), Delaro Complete (3+11+7), Revytek (11+3).

Decision Framework: 4 Game Plans

Not every field needs the most expensive fungicide. Match your spend to your risk level and yield environment. These four approaches cover the spectrum from maximum protection to no spray.

Iron Wall

$18-21/acre product + $8-12 application

Maximum protection. Premium triple-MOA product at full rate. For high-value corn (>$5/bu), known tar spot fields, or when disease pressure is confirmed high.

  • Product: Miravis Neo, Delaro Complete, or Revytek
  • Timing: VT-R1
  • Expected response: 8-15 bu/acre under moderate-high pressure
  • Breakeven: ~5 bu/acre at $4.50 corn

Smart Money

$12-16/acre product + $8-12 application

Best balance of efficacy and cost. Premium dual-MOA product. For fields with some disease history or moderate risk.

  • Product: Priaxor, Headline AMP, or Stratego YLD
  • Timing: VT-R1
  • Expected response: 5-12 bu/acre under moderate pressure
  • Breakeven: ~4 bu/acre at $4.50 corn

Budget Defender

$2-6/acre product + $8-12 application

Minimum effective coverage using generics. For lower-risk fields, tight margins, or as insurance when disease pressure is uncertain.

  • Product: Generic azoxystrobin ($2-3/acre) or Azoxyprop ($4/acre)
  • Timing: VT-R1
  • Expected response: 3-8 bu/acre under moderate pressure
  • Breakeven: ~2.5 bu/acre at $4.50 corn

Take a Knee

$0/acre

No fungicide application. Appropriate when disease risk is genuinely low: dry weather, no tar spot history, resistant hybrid, low corn prices.

  • Product: None
  • Best when: Dry forecast, clean hybrid, corn under $4/bu
  • Risk: Could lose 5-20+ bu/acre if conditions shift
  • Savings: $15-30/acre in input costs

Application Timing

University trials consistently show that VT (tasseling) to R1 (silking) is the optimal window for foliar fungicide application on corn. Timing matters more than product selection in most years.

V10-V14
Early vegetative. Generally too early for foliar. Exception: severe southern rust moving north early.
VT
Optimal. Tasseling. Maximum ear leaf protection. Best yield response timing in most trials.
R1
Optimal. Silking. Still excellent timing. Most commonly tested timing in university trials.
R2+
Blister/milk. Late. Reduced yield benefit. Only justified under extreme disease pressure (tar spot epidemic).

Key principles from the research:

One application at VT-R1 is the standard. Two-pass programs (V6 + VT) are rarely economical for corn based on university data.

Earlier is not better. Applying at V6-V8 leaves the upper canopy unprotected during the critical grain fill period when yield impact occurs.

Late applications can still help in tar spot epidemics. Indiana research (Ross et al. 2024) showed that even R2 applications provided some yield protection when tar spot pressure was severe.

ROI Calculator

Estimate the return on your fungicide investment. Adjust inputs to match your situation.

Product cost only. See pricing table above.
Ground rig: $6-8. Aerial/drone: $8-14.
Moderate pressure: 5-10. High pressure: 10-15+.
Gross Benefit
$36.00
Net Return
$8.00
Breakeven Yield Response
6.2 bu/acre

Frequently Asked Questions

What is the best fungicide for tar spot on corn?

Based on Crop Protection Network 2025 efficacy data, the top-rated products for tar spot control include Topguard EQ (Very Good), Veltyma (Very Good), and Revytek (Very Good). Triple-mode products like Miravis Neo and Delaro Complete also rate Good to Very Good. Products containing only FRAC Group 11 strobilurins generally have limited tar spot efficacy.

How much does corn fungicide cost per acre?

Corn fungicide costs range from about $1.43/acre for generic propiconazole (Tilt) to over $30/acre for premium products like Proline 480 SC. Popular mid-range options include Priaxor at $15-18/acre, Revytek at $18-19/acre, and Miravis Neo at $20-21/acre. Generic alternatives can cut costs significantly — generic azoxystrobin is $2-3/acre versus $7+/acre for brand-name Headline.

When should I apply fungicide to corn?

The optimal timing for foliar fungicide application on corn is VT (tasseling) through R1 (silking). University trials consistently show the best yield response at VT-R1. Applying at R2 (blister) can still help under heavy disease pressure but provides less yield protection. Applications before V10 or after R3 generally do not provide economic returns for foliar diseases.

Is it worth spraying fungicide on corn?

It depends on disease pressure, corn price, and fungicide cost. University research shows average yield responses of 5-15 bu/acre under moderate to high disease pressure, but near-zero response under low pressure. At $4.50/bu corn and $20/acre total cost (product + application), you need about 4.5 bu/acre yield response to break even. Use the ROI calculator above to model your specific situation.

What FRAC groups should I rotate for resistance management?

The three main FRAC groups in corn fungicides are Group 3 (DMI/triazoles), Group 7 (SDHI), and Group 11 (QoI/strobilurins). Avoid applying the same FRAC group repeatedly in a season. Premix products combining 2-3 groups (like Miravis Neo with Groups 7+11+3) inherently provide multi-site activity. If using a single-mode product, alternate between groups across applications.

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