What the research measured
The cited 240-trial analysis reported an average soybean yield response of about 1.6 bu/ac to an R3 fungicide application. Studies with frogeye leaf spot reported different responses. Disease pressure, active ingredients, and application costs are recorded in the linked research.
A 240-trial meta-analysis across nine states and Ontario (2005–18), a 66-trial eight-state frogeye analysis (2012–21), a four-state economic analysis and annual university trial programs.5 independent sources.What it is. A single pass of a premixed foliar fungicide, a strobilurin plus a triazole or SDHI partner, sprayed at beginning pod (R3) to protect soybean leaves from frogeye leaf spot, Septoria brown spot and other late-season diseases.
Study conditions and limitations
- Iowa State’s statewide R3 trials found no significant gain in 2021, 2022 or 2024, but +2.6 to +3.7 bu/ac for several premixes in 2025 even with low brown spot.
- Strobilurin resistance in frogeye, brown spot, target spot and Cercospora is present; the Crop Protection Network rates solo strobilurins Poor on frogeye, and pyraclostrobin efficacy fell 18 points over ten years. The source provides efficacy ratings by active ingredient.
- Purdue’s 2019 central-Indiana trials cut disease severity with seven premixes but found no significant yield difference in any of five trials.
- Timing is disease-specific: R3 is standard for frogeye and brown spot, white mold needs R1–R2, and R3 may not control Cercospora leaf blight.
- Response is larger with early planting and wet weather between planting and R3, and in average-yield fields; it shrinks as base yield rises.
Read the sources · 5
- Meta-analysis of soybean yield response to foliar fungicides evaluated from 2005 to 2018 in the United States and Canada ↗
240 field trials across nine US states and Ontario, all sprayed at R3: mean yield response 2.7% (110 kg/ha, about 1.6 bu/ac). Premixes of multiple fungicide groups gave 3.0%; the response was 4.7% in average-yield fields and fell as base yield rose. Less likely to be profitable when foliar diseases are absent or low.
- Efficacy and Profitability of Fungicides for Managing Frogeye Leaf Spot on Soybean in the United States: A 10-Year Quantitative Summary ↗
Network meta-analysis of 66 uniform trials (2012–21) in eight states with frogeye leaf spot: pyraclostrobin alone cut severity 11% and returned 136 kg/ha, while difenoconazole + pydiflumetofen cut severity 57% and returned 441 kg/ha, breaking even more than 65% of the time. Efficacy declined over time for several products.
- Analyses of Yield and Economic Response from Foliar Fungicide and Insecticide Applications to Soybean in the North Central United States ↗
Trials in Illinois, Indiana, Iowa and Nebraska (2008–14) under very low disease and insect pressure: fungicide alone was profitable in only 14% of site-years at $0.42/kg soybeans and a $62/ha application cost; fungicide plus insecticide in 45%.
- Fungicide Efficacy for Control of Soybean Foliar Diseases ↗
Multi-year, multi-location ratings by university pathologists: for frogeye leaf spot, Delaro, Miravis Top and Quadris Top SBX rate Good to Very Good while solo strobilurins Headline and Quadris rate Poor. Ratings are for disease control, not yield.
- To Spray or Not to Spray: Foliar Products at R3 ↗
In Ohio State soybean trials an R3 fungicide raised yield in 9 of 28 environments, by 4 to 8 bu/ac; responsive sites had brown spot and frogeye present and wetter years. A companion on-farm study found gains of 4.4 to 7.9 bu/ac at 4 of 12 site-years.
Before you buy, ask
- What disease pressure did the trials with a yield response have, and do my fields see it?
- What application timing and rate did the cited studies use?
- Is there a scouting threshold that would tell me whether to apply this season?
Record
- Sources checked
- September 26, 2026. Every figure shown is printed on the linked page; unit conversions are noted on the chart.
- Company response
- None yet. Makers and suppliers of this product can send corrections, additional trials, or a statement; it is published here, labelled, and never edits the research summary. Send a correction →