Effect of Foliar Fungicides on Frogeye Leaf Spot in Three Maryland Geographies in 2022
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 2022 to assess the efficacy of select fungicides for the suppression of soybean foliar diseases. Soybean ‘MAS3521E3’ were no-till planted into soybean residue at 150,000 seeds/A on 1 Jun at WMREC and 31 May at CMREC and WYE. All plots were 30 feet long and arranged in a randomized complete block design with 5 replications. Data was collected from the center 5-ft of each plot. The trial consisted of eight foliar fungicide treatments and a non-treated control. Fungicides were applied with a backpack CO₂-pressurized sprayer. Fungicides were applied at the R3 growth stage on 5 Aug at CMREC and WYE and 8 Aug at WMREC. Treatments with subsequent applications were made 14 days later. Yields were collected by harvesting the center 5-ft of each plot and adjusted to 13% moisture. Plots were harvested on 8 Nov at WYE, 18 Nov at CMREC, and 22 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, growing conditions were generally very favorable and 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 7 on a 10-point scale (10 being the most resistant). Yields were above average, and no significant differences were observed between treatments at any location. No phytotoxicity was observed with any of the fungicide treatments. Data for 2023 is being processed and will be uploaded to the Agronomy News Blog once available. This work was funded by the Maryland Soybean Board.
| 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 | 10.6 | 12.6 | 10.7 | 54.7 | 56.3 | 54.3 | 78.4 | 72.1 | 52.0 |
| Headline 2.09 EC/SC, 6.0 fl oz at R3 | 10.5 | 12.2 | 10.5 | 54.7 | 56.5 | 54.4 | 91.0 | 74.0 | 59.8 |
| Veltyma 3.34 S, 7.0 fl oz at R3 | 10.5 | 12.5 | 10.5 | 54.2 | 56.5 | 54.3 | 90.3 | 72.0 | 70.9 |
| Miravis Top 1.67 SC, 13.7 fl oz at R3 | 10.6 | 12.2 | 10.5 | 55.4 | 54.0 | 54.3 | 86.5 | 63.0 | 59.2 |
| Adastrio, 8.0 fl oz at R3 | 10.5 | 12.7 | 10.5 | 54.9 |
55.4 |
54.7 | 84.6 | 58.0 | 58.0 |
| Revytek 3.33 LC, 8.0 fl oz at R3 | 10.6 | 12.4 | 10.4 | 54.9 | 55.2 | 54.3 | 82.3 | 76.1 | 62.9 |
| Revytek 3.33 LC, 8.0 fl oz at R3 fb Revytek 3.33 LC, 8.0 fl oz 14 days after R3 |
10.6 | 12.7 | 10.5 | 54.8 | 55.4 | 54.2 | 83.6 | 58.9 | 60.9 |
| Lucento 4.17 CS, 5.0 fl oz at R3 | 10.5 | 12.4 | 10.5 | 54.6 | 55.4 | 54.4 | 83.4 | 67.2 | 62.6 |
| Lucento 4.17 CS, 5.0 fl oz at R3 fb Lucento 4.17 CS, 5.0 fl oz 14 days after R3 |
10.6 | 12.4 | 10.5 | 54.6 | 55.7 | 54.4 | 81.9 | 64.0 | 55.5 |
| p-value | 0.8716 | 0.3464 | 0.7067 | 0.2440 | 0.7375 | 0.9531 | 0.6583 | 0.7095 | 0.3133 |
ᶻ Means followed by the same letter are not significantly different based on Fisher’s Least Significant Difference (LSD; α=0.10).
This article appears in November 2023, Volume 14, Issue 8 of the Agronomy News.
Agronomy News, November 2023, Vol. 14, Issue 8
Agronomy News is a statewide newsletter for farmers, consultants, researchers, and educators interested in grain and row crop forage production systems. This newsletter is published once a month during the growing season and will include topics pertinent to agronomic crop production. Subscribers will receive an email with the latest edition.
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