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.

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.
o 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.
o 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:
Soybean variety MAS 3521E3 was no-till planted into soybean residue on May 31 at the Central Maryland Research and Center (CMREC) in Ellicott City and Wye Research and Education Center (WYE) in Queenstown and Western Maryland Research and Education Center (WMREC) on June 1. Plots are 11 feet wide by 20 feet long and planted on 15 inch rows (CMREC and WYE) and 30 inch rows at WMREC.

All plots have emerged and are approaching R3. Fungicide treatments will be applied at R3 using a CO2 backpack sprayer. After treatment application, disease ratings will be collected throughout the remainder of the season until harvest. Plots will be harvested at maturity to collect yield data. All data will be analyzed and final reports summarized.

Update:

View uploaded report

In previous years of this study, foliar fungicide applications with the selected products tested here provided some benefit related to improved seed quality and yield in situations where frogeye leaf spot disease pressure was present at measurable levels. Fungicides also significantly increased plant greenness and delayed senescence.

During the 2022 growing season, however, none of the treatments tested yielded significantly different than the non-treated control. This is likely due to the fact that no ratable foliar fungal diseases were present in the plots this year. Without the presence of a pathogen, fungicides have reduced odds of improving yields over non-treated plots.

Relative net profit was calculated by multiplying the bushel increase over the non-treated control by the cash market price for soybean at the time of analysis (14.60/bu for 2022) and subtracting the cost of application. A flat rate of $26.00 per acre was used for 2022 data; for plot with two applications, $52 was used. This metric, net profit, was used to compare the economics of the fungicides while accounting for yield and market prices. For the 2022 trials, this comparison yielded no significant differences. However, when compared across all seasons (2022-2023), a single fungicide application at R3 significantly increased profits by an average of $38 per acre compared to the two-pass program, which lost an average of $26 per acre.

Future work will be focused on replicating similar experiments over more plot-years to gather more data for Maryland’s unique growing conditions and to track pathogen resistance and fungicide profitability over time.