AMES, Iowa – For the past 28 years, the mission of the SCN (Soybean Cyst Nematode) Coalition has been to increase farmer awareness of SCN, as well as the number of soybean farmers actively managing the pest to protect the sustainability of the U.S. soybean industry.

The coalition has organized and used numerous innovative activities and communications approaches in recent years to help soybean farmers actively manage soybean cyst nematode, according to Greg Tylka, Iowa State University (ISU) professor of plant pathology and microbiology, and director of the Iowa Soybean Research Center, who established the coalition in 1997.

“Among the most original and popular efforts are the educational campaigns ‘National Nematode Day’ (each year on Oct. 6th), ‘SCN Action Month’ (in October), and ‘Are you Smarter than a Nematode?’ quiz sweepstakes,” Tylka said.

According to the coalition, the microscopic, soil-borne soybean cyst nematode is considered the most serious biological threat to the U.S. soybean industry. In North America, it causes yield losses worth more than $1 billion annually.

Today, the coalition includes university scientists from 28 states and Ontario, Canada, grower checkoff organizations, and corporate partners. Much of the funding for the coalition and related research has come from checkoff funds from the North Central Soybean Research Program, the United Soybean Board, the Iowa Soybean Association, and other soybean commodity groups.

Tylka said, “The coalition has achieved incredible reach and success by conveying science-based information about the biology and active management of SCN, using consistent terminology and unified messages delivered to farmers by university, checkoff organization, and industry personnel in creative, yet research-based, terms. This approach minimizes the possibility of confusion or mixed messages, and has proven to be very effective, as shown in various market research survey results.

“Another creative and award-winning approach the coalition has undertaken to help farmers combat SCN is the SCN Profit Checker (SCNProfitChecker.com),” he added. “This is an online tool that farmers and those who advise them can use to estimate the extent of the yield loss that can be caused by SCN in specific fields.”

He said users of the calculator submit a few known and important pieces of information about an SCN-infested field and the calculator will provide a data-based estimate of the yield loss SCN will likely cause for that field.

“The yield loss estimate is expressed both in bushels per acre reduced, and in dollars per acre lost,” he said. “The calculator is powered by an algorithm that we developed, using data collected from 35,000-plus Iowa State University field research plots over 23 years. Use of the calculator is completely anonymous (no data are tracked or saved), and the calculator has been used nearly 90,000 times since it was launched in September 2023.”

Each year, ISU Extension and Outreach publishes a list of commercially available, SCN-resistant varieties in the fall. A preliminary version of the list for 2026 is available at: www.thescncoalition.com.

He said growing resistant varieties is the best management tactic for SCN when growing soybeans, adding that the nematodes still become “resistant to resistance.”

“So in soybean years, we encourage farmers to alternate growing soybeans that have the two different genetic types of SCN resistance in order to slow the loss of effectiveness of resistance,” he said. “We also recommend growing non-host crops such as corn in alternating years to disrupt the pest’s life cycle, and there are several nematode-protectant seed treatments that farmers should evaluate when growing soybeans in SCN-infested fields.”

In addition, the coalition’s tagline, “What’s Your Number? Take the Test. Beat the Pest” encourages farmers to use the SCN ProfitChecker to see an estimate of SCN’s economic toll on their fields. With that information, they can select the best resistant soybean varieties for their location, and also consider using other management practices. The coalition regularly shares ever-changing information about SCN population levels, the availability of resistant soybean varieties, and yield results for SCN-resistant varieties with different genetics.

Ed Anderson, executive director of the North Central Soybean Research Program in Ankeny, Iowa, who has long been involved in the coalition and its outreach efforts, said the coalition’s efforts have been very effective at raising awareness and developing solutions through helping farmers make the best decisions for short-term management, based on extensive field trials and effective communication and outreach on currently available solutions and recommendations.

The coalition’s efforts also include working with soybean breeders to develop more diverse genetics to fight SCN, and encouraging companies to license the genes and breeding materials, and put them into commercial use, as well as looking for new solutions through promoting basic and applied research to combat SCN and other nematode pests.

“This pest is not going away,” Anderson said. “We have to stay ahead of it if we’re going to be able to grow soybeans profitably into the future.”