Research HighlightsWhite Mold ROI Calculator Available for North Central Farmers
Highlights:
- A new tool, the White Mold ROI Calculator, can help farmers with economics of fungicide applications.
- After years of data collection across the North Central region, soybean pathologists pooled their findings to create the calculator.
- The calculator is free, simple to use, and housed on the Crop Protection Network website along with other useful tools.
By Carol Brown
After more than eight years of data collection and analysis, a new tool is available to help farmers with decision making for white mold control. The White Mold ROI Calculator helps farmers and agronomists determine the economic value of fungicide application based on disease severity, fungicide and application costs.
The calculator is an outcome of research on the sclerotinia sclerotium pathogen in the North Central U.S. The research has been supported since 2018 with Soy Checkoff funding from the North Central Soybean Research Program (NCSRP). Several scientists have led research projects through NCSRP on this pathogen with Richard (Wade) Webster now at the helm.
“Farmers in the North Central U.S. deal with white mold more than those farming in the mid-south or deep south, due to moisture levels and soil temperatures during soybean flowering stages,” explains Webster, soybean pathology specialist at North Dakota State University. “We’ve been running uniform foliar fungicide trials for white mold management across the North Central region and this is a culmination of our collected datasets. The development of the calculator came about over the past two years. It’s free and anyone can use it.”
The White Mold ROI Calculator was built with many states’ data in the region, and includes prices of eight different fungicide programs through ag retailers from North Dakota to Ohio. The fungicide costs in the calculator reflect the median value across all the contacted retailers.
Users can adjust the fungicide prices if they know what their local co-op charges. They can also adjust the severity level of white mold they see in their fields, the current soybean price, projected yield, and application costs.
“We’ve included a base application cost, which I think is distinctive from other tools. This can be adjusted in the calculator and it should include cost of a contracted applicator, or equipment, whether it’s rented or owned,” Webster explains. “Even if farmers use their own equipment for application, it is still not free, as depreciation and maintenance are part of the cost.”
The calculator will show whether a fungicide application will have a positive or negative return on investment (ROI), based on soybean projected yield, price point and disease level. The analysis displays the net benefit and break-even disease severity index percentage by product.
Fungicides Plus Management for Success
“The Sclerotinia sclerotiorum pathogen can survive anywhere, but it needs specific environmental conditions at the soybean flowering stage,” he comments. “Consistent moisture is key and it doesn’t mean just rainfall; high humidity levels that lead to dew on the leaves and on the soil surface play a part as well. The apothecia, or the fruiting bodies, of the fungus will develop as a lot of moisture is retained along with cooler soil temperatures inside the soybean canopy.”
Farmers can use several practices to reduce white mold severity. Genetic resistance is the first tool farmers have, says Webster, and there are several soybean varieties that have higher levels of white mold resistance. There are no varieties completely resistant to white mold, he notes, and farmers need to be aware that resistance scales are not consistent between seed companies.
“There is inconsistency within disease ratings of white mold. Generally, they are all susceptible, but a degree of 9 at one retailer could be considered the best, but at another retailer, a 9 could indicate the least resistant,” he cautions.
In addition to genetics, wider row spacing and lower planting populations can help reduce white mold. Wider rows and fewer plants allow for moisture to decrease quicker within the canopy and delay the fungal growth.
“There are also certain biological chemicals that can help break down the pathogen in the soil so it doesn’t become an issue,” Webster says. “And longer crop rotations beyond corn and soybean can help reduce severity. In North Dakota, farmers can add small grains into the rotation to increase the time before the next soybean crop is planted.”
Other White Mold Tools
In addition to the White Mold ROI Calculator, other tools for soybean diseases are housed at the Crop Protection Network. The former Sporecaster app — a prediction tool for fungicide applications to control white mold — is now part of the Crop Disease Forecasting Tool so farmers can conduct risk assessments for several crop diseases at one location.
The White Mold ROI Calculator and Crop Disease Forecasting Tool are hosted by the Crop Protection Network. Management and maintenance of the tools are supported by USDA-NIFA and United Soybean Board.
Additional Resources
White Mold ROI Calculator – hosted by Crop Protection Network
Initial NCSRP research project – National Soybean Checkoff Research Database
Managing White Mold in Soybeans – University of Wisconsin YouTube video
Meet the researcher: Richard Wade Webster SRIN Profile | University Profile
Published: Sep 22, 2025
The materials on SRIN were funded with checkoff dollars from United Soybean Board and the North Central Soybean Research Program. To find checkoff funded research related to this research highlight or to see other checkoff research projects, please visit the National Soybean Checkoff Research Database.
