2023 Maryland Soybean Fungicide Trials
Trials were established at the Wye Research and Education Center in Queenstown, MD (WYE), Central Maryland Research and Education Center in Ellicott City, MD (CMREC), and Western Maryland Research and Education Center in Keedysville, MD (WMREC) in 2023 to assess the efficacy of select fungicides for the suppression of soybean foliar diseases. Soybean ‘MAS3220E3’ were no-till direct-seeded into soybean residue at 150,000 seeds/A on 16 May using a 6-row John Deere 1750 planter set on 30-in row spacing at WMREC. Plots were drilled on 7.5-in rows on 22 May at CMREC and 15 May at WYE using a 10-foot John Deere 1590 no-till drill and a Great Plains EWNT-10 drill, respectively. All plots were 30 feet long and established in fields with a previous crop of soybean. Plots were arranged in a randomized complete block design with 5 replications. Data was collected from the center 5-ft of each plot. Soybean cultivation practices were consistent with recommendations from the University of Maryland Extension. The trial consisted of 9 foliar fungicide treatments and a non-treated control. Fungicides were applied with a backpack CO2-pressurized sprayer outfitted with TeeJet 8003 nozzles calibrated to deliver 20 GPA at 35 psi to the center 80-in of each plot. Fungicides were applied at the R3 growth stage on 2 Aug at WYE and 9 Aug at CMREC and WMREC. Treatments with subsequent applications were made 14 days later. Based on the disease history of these fields and monoculture soybean rotation, natural pathogen inoculum levels were utilized for disease infection. Yields were collected by harvesting the center 5-ft of each plot using an Almaco R1 combine, and yields were adjusted to 13% moisture. Plots were harvested on 24 Oct at WYE, 7 Nov at CMREC, and 9 Nov at WMREC. Data were analyzed using ANOVA, and significant differences between treatments were separated using Fisher’s Least Significant Difference (LSD; α=0.10).
The most predominant foliar pathogen at all locations was frogeye leaf spot (Cercospora sojina); however, no disease was observed at a ratable level. This is likely due to the weather conditions around pod fill, as well as the resistance package in the soybean variety, which has a frogeye leafspot resistance rating of 6 on a 10-point scale (10 being the most resistant). No significant differences in yield, test weight, or moisture were observed between treatments at any location. No phytotoxicity was observed with any of the fungicide treatments.
| Treatment, rate/A and timing | Grain Moisture (%) | Test Weight (lb) | Yield (bu/A) | ||||||
|---|---|---|---|---|---|---|---|---|---|
| WMREC | CMREC | WYE | WMREC | CMREC | WYE | WMREC | CMREC | WYE | |
| Non-treated control | 11.6 | 14.7 | 12.4 | 55.5 | 57.5 | 57.7 | 42.4 | 60.6 | 73.0 |
| Headline 2.09 EC/SC, 12.0 fl oz at R3 | 11.8 | 14.3 | 12.3 | 56.9 | 57.1 | 57.8 | 46.6 | 63.8 | 76.0 |
| Veltyma 3.34 SC, 10.0 fl oz at R3 | 11.7 | 14.4 | 12.2 | 59.1 | 56.5 | 57.6 | 49.8 | 60.8 | 77.2 |
| Priaxor 4.17 SC, 8.0 fl oz at R3 | 11.8 | 14.3 | 12.3 | 55.3 | 58.2 | 56.8 | 47.4 | 63.1 | 74.7 |
| Lucento 4.17 CS, 5.5 fl oz at R3 | 11.9 | 14.6 | 12.2 | 58.5 | 58.0 | 57.4 | 46.7 | 58.8 | 78.0 |
| Topguard EQ 4.29 SC, 8.0 fl oz at R3 | 11.9 | 14.7 | 12.5 | 58.3 | 57.1 | 57.1 | 42.2 | 57.6 | 72.4 |
| Revytek 3.33 SC, 15.0 fl oz at R3 | 11.9 | 14.1 | 12.3 | 58.7 | 57.9 | 57.6 | 45.7 | 66.8 | 74.5 |
| Revytek 3.33 SC, 15.0 fl oz at R3 followed by Revytek 14 days after R3 |
11.9 | 14.7 | 12.2 | 59.0 | 57.5 | 57.6 | 43.4 | 58.8 | 77.6 |
| Adastrio 4 SC, 5.5 fl oz at R3 | 11.9 | 14.3 | 12.4 | 58.8 | 57.8 | 57.4 | 47.8 | 63.6 | 72.0 |
| Adastrio 4 SC, 5.5 fl oz at R3 followed by Adastrio 14 days after R3 |
11.8 | 14.7 | 12.4 | 56.3 | 58.2 | 57.5 | 43.3 | 56.9 | 72.0 |
| p-value | 0.8806 | 0.3267 | 0.2030 | 0.7567 | 0.6191 | 0.7071 | 0.4331 | 0.6580 | 0.4046 |
This article appears in July 2024, Volume 15, Issue 4 of the Agronomy News.