- Vayantis® fungicide seed treatment contains a novel active ingredient that provides new options for managing diseases from pathogens like Pythium spp. and Phytophthora spp.
- Vayantis seed treatment may provide the greatest benefit to soybeans in environments where traditional seed treatments have lost efficacy by adding a second mode of action against Pythium and Phytophthora.
Management Options
Poor stand establishment in soybeans has several culprits. Early planting into cooler soils can slow emergence and make soybeans vulnerable to soilborne disease or insect damage. Reduced or no-till fields with large amounts of residue can further exacerbate these risks. More than one disease pathogen, such as Pythium spp., Phytophthora spp., Fusarium spp. or Rhizoctonia spp., can be responsible for poor stand establishment in early planted fields (Figure 1).
Planting later into warmer, drier soils can lessen stand establishment risks, but this may sacrifice yield advantages often seen with earlier planting. Unforeseen spring weather could further delay planting, resulting in even greater yield loss. Seed treatments such as CruiserMaxx® Vibrance® and CruiserMaxx® Vibrance® Beans have historically provided good protection against multiple diseases. However, the primary active ingredient used for Pythium management was introduced almost 4 decades ago and has been highly utilized on both corn and soybean seed. Continued use of a single herbicide, insecticide or fungicide is unsustainable for resistance management. Thus, pesticides that have multiple sites of action for an individual pest are recommended. Picarbutrazox, a new active ingredient that will be marketed as Vayantis fungicide seed treatment, contains a novel mode of action (MOA) that has shown great activity on both Pythium and Phytophthora species.
Seed Treatment Trials
The Golden Harvest® Agronomy in Action Research team conducted trials at 8 locations (Figure 2) in the 2020 growing season to evaluate the potential of Vayantis seed treatment as a second MOA when added to CruiserMaxx Vibrance base seed treatment.
Each location compared an untreated check, CruiserMaxx Vibrance seed treatment and CruiserMaxx Vibrance + Vayantis seed treatments on 2 varieties. The soybean varieties planted were either GH2537X and GH2788X or GH3546X and GH3759E3S, depending on which relative maturity (RM) best fit the location.
Results
In general, locations with the 3.4-3.7 RM variety set had good stand establishment and lacked yield differences between treatments due to lack of disease presence. However, many of the 2.5-2.7 RM locations observed yield and/or plant stand differences among treatments. Seed treatment responses were similar across the 2 varieties at each location. Therefore, results were averaged across location to see the main effects of the seed treatments.
Adding Vayantis seed treatment to CruiserMaxx Vibrance increased stands by 3,000 and 6,000 plants/acre at Slater and Cedar Rapids, IA, respectively. Across Slater, Cedar Rapids and Sac City, IA, stands were, on average, 1,000 plants/acre more than CruiserMaxx Vibrance alone and 10,000 plants/acre more than the untreated entries (Graph 2). There were numerical yield advantages from adding Vayantis to CruiserMaxx Vibrance at Slater (4.2 bu), Sac City (2.2 bu) and Cedar Rapids (2 bu), but only a 0.4 bushel advantage was observed when averaged across all locations (Graph 1).
Summary
Although CruiserMaxx Vibrance provided adequate protection against Pythium in 2020 research trials, adding Vayantis increased yield potential by small increments and improved final stands at several locations with higher disease pressure. This indicates that the unique mode of action Vayantis provides may be a good complementary fungicide seed treatment to use as Pythium spp. continue to evolve and adapt to previous management practices.
Vayantis benefits will likely be more obvious in fields where current seed treatments have not been able to fully achieve maximum stand establishment. Unlike when introducing a new active ingredient for managing a previously uncontrolled disease, the value of Vayantis may not be as easily observed on a frequent basis, but it should ensure consistent protection in future years.
For more information on seed treatment options for your soybean crop, contact your local Golden Harvest Seed Advisor.
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