Is Fungicide Efficacy Affected by Application Time-of-Day?

TRIAL OBJECTIVE

• Fungicides have been widely adopted by soybean growers, with some farmers making or considering two or more applications in a season.^1,2
• Farmers interested in maximizing their input costs may wonder whether there is an optimum time-of-day for fungicide applications.
• This research was conducted with a goal of determining whether the time of fungicide application during the day has any impact on crop yield potential.

RESEARCH SITE DETAILS

• This research was conducted in Woodford County, Illinois in 2021 and 2022.
• Trials located in grower fields with treatments repeated twice (2 reps) at each location.
• Soybean products ranging from 3.1 to 3.7 Relative Maturities (RM) were planted.
• Standard fertility and weed management practices were followed.
• Delaro^® Complete Fungicide was applied at the R3 soybean growth stage.
• Fungicide applications were made in the morning (~8:00 AM), mid-day (~12:00 PM), and evening (~5:00 PM).

UNDERSTANDING THE RESULTS

• Averaged across all treatments, no significant yield differences (LSD=2.15) were observed between fungicide application timing during the day (Figure 1).
• Two out of three locations exhibited a minor trend of lower yield after the evening application.
• Disease pressure was low to moderate for both years.

KEY LEARNINGS

• In this research, fungicide application timing during the day did not have a significant impact on average yield potential.

Sources:

¹Carr, J. 2019. Soybean fungicide application advice. ILSoyAdvisor. Illinois Soybean Association. https://www.ilsoyadvisor.com/soybean-fungicide-application-advice/.

²Schmidgall, S. 2019. Applying foliar fungicide on soybeans. ILSoyAdvisor. Illinois Soybean Association. https://www.ilsoyadvisor.com/applying-foliar-fungicide-soybeans/

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