2020
Does Early Planting Date Justify Fungicidal Seed Treatment in Soybeans?
Category:
Sustainable Production
Keywords:
Crop protectionDiseaseField management
Lead Principal Investigator:
Rachel Vann, North Carolina State University
Co-Principal Investigators:
Project Code:
19-082
Contributing Organization (Checkoff):
Institution Funded:
Brief Project Summary:

Some North Carolina producers are starting to shift soybean planting earlier into the spring due to success with early maturing soybean varieties. Most of the fungicide seed treatment work conducted by the Soybean Extension Program has been done with soybeans planted from mid-May through mid-June. How would our results differ when considering planting soybeans earlier in the season? This research seeks to answer this question. It evaluates fungicidal soybean seed treatments across four planting dates ranging from early April through mid-May. Economic analyses consider both fungicidal seed treatment cost and impact on soybean yield.

Key Benefactors:
farmers, agronomists, extension agents

Information And Results
Project Deliverables

Final Project Results

The goals of this project were to determine whether planting date affects the necessity of a fungicidal seed treatment in soybeans and to identify the most effective fungicidal seed treatment in early planting situations. In 2019 and 2020, research was conducted at six NC locations (Beaufort (2019 and 2020), Robeson (2020), Rowan (2020), Sampson (2019), and Yadkin (2019) Counties) to answer these questions. We compared three soybean planting dates (late March to early April, mid to late April, and mid-May) across three soybean maturity groups (III, IV, V). We compared four-five fungicidal seed treatments to an untreated control within each planting date and maturity group combination.

A fungicidal seed treatment protected stand at two of the six locations across planting dates and maturity groups; the impact was similar across fungicidal seed treatments. In 2019, the use of a fungicidal seed treatment protected yield (+5.9-6.9 bu/A) across planting date and maturity groups at two locations. There was no impact of fungicidal seed treatment on yield at locations in 2020. Nonetheless, if you broke down the yield protection from the use of a fungicidal seed treatment across the planting dates in both years, there was more protection of both soybean stand and yield at earlier planting dates. It is therefore our recommendation at this time based on this two-year data set that growers planting earlier than Mid-May consider the use of a fungicidal seed treatment to protect soybean stand and yield in fields with a history of seedling disease pressure, as environmental conditions at earlier planting dates can be more conducive
to seedling disease development. Our results indicate that when multi-mode of action fungicidal seed treatments are used, they typically provide similar protection of soybean stand and yield between industry-leading products.

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.