Farmers looking to decide when to apply a soybean foliar fungicide can get their biggest ROI from the application by determining the crop’s growth stage, says Matt Duesterhaus, Crop-Tech Consulting research agronomist.
Right now in the Midwest (late July), many soybean crops are somewhere in the midst of the R2 to R4 growth stages.
A growth stage begins when 50% or more of the soybean plants are in or beyond a specific stage, according to Iowa State University Extension.
Duesterhaus says that during the R2 to R4 growth-stage range, you start seeing some of the biggest yield moves—both up and down—in soybeans.
“These pod development stages are about finalizing the potential for soybean yields,” Duesterhaus explains. “From R2 to R4, we need to do everything we can to protect the beans so they can hang onto those flowers as pods. Then, in August, we see how we can fulfill the potential out there.”
Duesterhaus provides additional insights in the brief video recorded this week during the 2024 Farm Journal Corn & Soybean College in Heyworth, Ill.
Watch the video here: https://www.youtube.com/watch?v=0UByvOkbx-g
Fungicide Efficacy Insights
Stephanie Porter, Outreach Agronomist for the Illinois Soybean Association, says it’s important to correctly identify what specific soybean fungal disease is present at growth stage R3. Then, you can determine what fungicide mode of action groups will provide the best fungicide efficacy to achieve maximum disease control.
In an online article, Porter says the North Central Regional Committee on Soybean Diseases has developed information on foliar fungicide efficacy for control of major foliar diseases.
“These efficacy ratings are based upon the level of disease control achieved by the product and are not necessarily reflective of yield increases achieved by the product application,” Porter says. “Efficacy will depend on the right application timing, rate, and method of application and this is outlined in product label instructions to achieve the optimum effectiveness of the fungicide.”
Read her complete article at Staging Soybeans for Fungicide at the R3 Growth Stage
Learn more about staging soybeans at:
Understand the Soybean’s Journey from Planting to Harvest
Study Soybean Growth To Build Up Yield
Want to Take More Beans to the Bin at Harvest?
