1. Evaluate the efficacy of 10 foliar fungicides on full season soybeans grown on two research farms in Maryland by
measuring foliar disease incidence and severity
2. Determine any greening or green stem effects of the fungicides
3. Monitor fungicide active ingredient efficacy over time and identify any fungicide insensitive foliar fungal pathogens
4. Determine the yield impact of foliar fungicides and their economic impact.

1. Evaluate the efficacy of 10 foliar fungicides on full season soybeans grown on two research farms in Maryland by
measuring foliar disease incidence and severity
2. Determine any greening or green stem effects of the fungicides
3. Monitor fungicide active ingredient efficacy over time and identify any fungicide insensitive foliar fungal pathogens
4. Determine the yield impact of foliar fungicides and their economic impact.

A full-season commercial soybean variety with good yield potential representative of what’s typically grown in Maryland and will be purchased for use in all trials across all site locations. A soybean variety with a medium rating for frogeye leaf spot and other foliar diseases will be chosen in order to maximize chances of observing response to fungicide applications.

Seed will be direct seeded into soybean residue on three site locations (Western MD Research & Education Center in Keedysville, MD and the Wye Research & Education Center in Queenstown, MD, and Central Maryland Research & Education Center). Plots will be drilled on 7.5 inch rows, 10 feet wide by 30 feet long, arranged in a randomized complete block design.

Fertility and crop management (weeds and insects) will be managed in accordance with extension guidelines.

Stand counts will be conducted approximately two weeks after planting to assess emergence.

Fungicides for the trial will be submitted by chemical companies for testing for a fee. Fees will be used to offset costs and sustain the program for future years of research. Some products may also be purchased and used as checks in the test. All fungicides will be applied per the maximum label rate per label instructions. Fungicides will be applied with a CO2 backpack sprayer.

Foliar disease ratings will be assessed prior to treatment application and ratings will continue biweekly until soybeans reach maturity. NDVI ratings (plant greenness) will also be collected to determine any “greening” effect of the treatments. Green stem ratings will be collected at R8. Disease, NDVI, and green stem ratings will be compared statistically. Disease ratings will be used over time to compare and track any changes in pathogen resistance to specific active ingredients.

Plots will be harvested with a small plot research combine at maturity. Yields for each plot will be calculated and a statistical analysis will be done to compare treatment yields to determine if there’s any treatment effect. Yield and treatment cost will be used to calculate and compare possible economic benefits of fungicides on full season soybeans.

Data from this study will be published in extension publications and/or peer-reviewed crop production journals. Data will also be presented to growers at regional and statewide meetings and newsletters on an annual basis so that growers can view the most recent fungicide data for soybeans.

Update:
Plots have been established at three UMD research centers; Wye Research and Education Center (WYE; Queenstown, MD), Central Maryland Research and Education Center (CMREC; Clarksville, MD), and Western Maryland Research and Education Center (WMREC; Keedysville). Plots were planted on May 16, 2023 at WMREC, May 18 at WYE, and May 22 at CMREC. All plots were planted with soybean var. MAS 3220 E3. All locations had good emergence and are currently at the R1 growth stage. Fungicides will be applied at the R3 growth stage. Currently only very low levels of disease are present in the trials.

Data from last year's fungicide efficacy trials have been submitted and accepted for publication in the Plant Disease Management Reports journal.

Update:

View uploaded report

Foliar fungicides applied at R3 or R3+14 days did not provide a yield benefit in this trial. Data analyzed across multiple site years (from 2021-2023) indicate the single fungicide application at R3 provides the greatest net return on investment of $29/acre compared to a two fungicide pass program (-$26/acre). Fungicides also delayed plant senescence compared to the non-treated control.

Fungicides are becoming increasingly popular in full season soybean production. Land grant institutions across the US and in surrounding states have robust applied research programs where industry ag chemical companies submit new products and formulations for testing for the management of soybean diseases; such a project has been absent in Maryland for several years, creating a dearth in knowledge of fungicide efficacy for our soybean producers in Maryland. This project will provide data that soybean producers would benefit from, such as: fungicide efficacy for managing common fungal diseases of soybean, monitor fungicide resistant pest populations, and track the economic impact of foliar fungicide applications over multiple years and environments unique to Maryland.