One important component of a successful high-yielding soybean management program is to understand when and how to apply fungicides, as well as which products to use. This webinar will provide an in-depth explanation about how timely fungicide applications can be leveraged to mitigate soybean stress.

Presenter: Jason Carr, CCA & Bayer Crop Science Technology Development Representative

Jason holds a bachelor’s degree in natural resources and environmental sciences and a master’s degree in molecular genetics from the University of Illinois at Urbana-Champaign. He is currently a technology development representative with Bayer Crop Science, where he leads agronomic research projects with corn and soybeans focused on creating tailored solutions for growers. Prior to his current role, Jason spent a decade in soybean breeding with Monsanto as part of a team developing numerous commercially successful varieties in RM groups 2 and 3. Jason is also a 2021 CCA Soy Envoy, a position he held in 2019 and 2020.

Download Carr’s PowerPoint Presentation.

• A fungus is a group of unicellular, multicellular, or syncytial spore-producing organisms that can’t produce their own food and need to feed on other organisms
  • Can attack plant in many different ways and can spread in many ways (wind, rain, insects, birds, machinery, contaminated seed)
• Plant disease triangle
  • Disease only occurs if three things are present at the same time:
    • Pathogen
    • Host
    • Environment
  • Manipulating a component or combination of triangle components influences the incidence and severity of disease
• Resistance (genetic) prevents or slows down a successful infection by the pathogen in the host.
  • Works best with a good fungicide
  • High levels of pathogen and a good environment will overcome resistance
  • Most economically-efficient and environmentally friendly way to control disease
• Protection (chemical) prevents infection and establishment of a pathogen in a susceptible host
  • Prevention usually happens before infection
• Fungicides are used to:
  • Control disease
  • Increase productivity of a crop
  • Improve the storage life and quality of harvested material
• Fungicidal seed treatments are critical for early planting
  • Choose a fungicidal seed treatment that will protect the seed against multiple diseases
  • See biggest advantage in protecting yield potential when used early in the season
• Foliar fungicide applications often improve yield potential for most popular varieties, hybrids and cultivars
• Most fungicides used today are systemic
  • Absorbed into the plant and protects from the inside out
  • However, more likelihood of developing disease resistance if don’t use multiple modes of action
• Fungicide classes and mode of actions:
• Quinone Outside Inhibitors (Qols)/Strobilurins
  • Best when used preventatively
  • Stop spore from developing
  • Soybeans treated with strobilurin fungicides often tolerated moisture stress better
• Demethylation Inhibitors (DMIs)/Triazoles
  • Prevent, cure and protect the plant
  • Once a plant is infected, it can stop the infection from getting worse
• Succinate Dehydrogenase Inhibitors (SDHIs)
  • Preventative with some curative
  • Stop fungus from respiring
• Importance of multiple modes of action
  • Broaden performance
    • Combine strengths
    • Increase consistency across weather conditions
  • Attack the fungi in multiple ways
    • Both preventive and curative
  • Critical for resistance management
    • More than one must have activity on pathogens
    • Mixtures are better than solos
• Fungicide applications protect yield potential by helping soybeans manage stress
  • Untreated soybeans lost pods; treated soybeans protected pods
  • Leaving yield on the table by not using fungicides
• Timing and method of fungicide application
  • Soybeans should be sprayed between R2 and R4
  • Timing isn’t critical, more important to get it on
    • Exception for certain diseases, like white mold
      • R1 and R3 applications to control white mold
  • Better efficacy in higher humidity
  • Research shows similar response to aerial and ground application
• Local research
  • 85-location data set
    • 93% of growers saw a win rate
    • 82% saw an economic advantage to spraying fungicide
    • Average 4.8 bushel-per-acre advantage
  • Soybean yield responses to fungicide and variable population
    • Higher pop = more disease development
      • However, see a consistent yield response to fungicide treatment across populations
      • Often see a better response in lower populations
    • A population around 120,000 seeds with a fungicide produces the best ROI
  • Fungicide treatments do not appear to affect on maturity
    • Stems stay green a little later, which may push harvest later, but often the highest yielding varieties
    • Later soybeans had an increase in moisture at harvest