An evaluation of SCN seed treatments for managing SCN and SDS symptoms to develop Missouri specific management recommendations.

1. Evaluate SCN seed treatments for their ability to control and manage SCN in Missouri.
2. Determine if SCN seed treatments reduce SDS foliar symptoms.
3. Assess how well SCN seed treatments perform across environments.

The data generated by this project will allow for the development of Missouri specific information regarding the performance of SCN seed treatments on SCN and SDS. These impacts will be realized in the following ways: first, the information collected will be used to evaluate emerging tools in the SCN management toolbox and how nematode protectant seed treatments perform in Missouri soils; and second, this project will allow for a better
understanding how newly developed SCN management tools impact the development of SDS symptoms.

Updated April 27, 2021:
Seed treatments for the protection and control of soybean sudden death syndrome (SDS) and soybean cyst nematode
(SCN) have become more widely available through numerous companies. As these two diseases are the most damaging diseases of soybeans and begin early in the growing season, treatment must begin early in the season. Often, the presence of SCN in a field increases the foliar disease severity of SDS symptoms. This research study was specifically
developed to better understand how nematode-protectant seed treatments can be used to control and manage these two important diseases of Missouri soybeans.

Trials were conducted at four MU research centers spanning the state. Continuing the nematode-protectant seed
treatment trials that were initiated in the 2019 growing season, the 2020 trials were expanded to include 3 additional products for a total of 8 seed treatment products. All nematode-protectant seed treatments were compared to a base fungicide + insecticide and naked seed. Additionally, each field site represented a range of SCN egg levels and SDS risk levels. Nematode reproduction, sudden death syndrome foliar symptom severity, and soybean yield were measured for each plot, and comparisons were made among treatments.

Much like was observed in the 2019 season, results of the 2020 trials indicated differences among treatments at the
Graves-Chapple research station. Differences among SDS foliar disease severity, SDS root rot, and soybean yield were
observed at this location. Overall, lower SDS foliar disease severity and SDS root rot were observed in the ILeVO® and
Saltro® containing treatments as compared to the nontreated control. Significantly higher yield also was observed in these same treatments as compared to the non-treated control and the Clariva® treatment at this single location. At
no other location in Missouri and for no other treatments was there a significant difference as compared to the
non-treated control or among treatments. Overall, environment, SCN initial egg counts, and SDS field history are the biggest factors driving the effectiveness of nematode-protectant seed treatments.

This study will generate relevant, timely SCN and SDS management information which will be disseminated through the "Missouri Certified" Strip Trial Scouting Schools and other Extension programming for producers throughout the state.