Ontario Grain Farmer March 2024

12 Research Fighting soybean disease RESEARCHERS FOCUS ON SCN AND WHITE MOLD Rebecca Hannam ONTARIO IS THE 10TH LARGEST SOYBEAN PRODUCING REGION in the world and is home to a variety of innovative research programs that advance crop production and market opportunities. Developing integrated disease management strategies and breeding for disease resistance are key research areas to help farmers protect soybean yield. Two three-year research projects that support the management of soybean cyst nematode (SCN) and white mold will conclude in 2024. THE SCN COALITION SCN is the most yield-limiting disease and plant health issue in soybeans in North America and is estimated to cost farmers $1 billion (USD) annually. While the most significant losses are currently in the U.S., Ontario losses are expected to increase rapidly in the coming years as the erosion of SCN resistance (conferred by P188788 genetics) becomes more widespread. The issue is also becoming more present in Quebec and Manitoba. Dr. Milad Eskandari, associate professor and plant breeder at the University of Guelph, and Albert Tenuta, field crop plant pathologist, Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA), have worked to advance SCN research and increase grower awareness through a multifaceted project. Their objectives included surveying Ontario fields for nematode population and distribution, evaluating nematicides and other products for SCN control, and continuing to work with the SCN Coalition, a partnership with university scientists from 28 US states, commodity boards, and other stakeholders. “By partnering with our colleagues, from both extension and research, we’re able to utilize our strengths and resources to maximize our efforts and ultimately get one message and one voice across to soybean producers in North America,” says Tenuta. PRACTICAL RESEARCH Soil samples collected across the province confirm that all soybeanproducing areas have SCN. As expected, the highest frequency was in the southwest (Oxford to Essex counties), although detection continues to increase in Northumberland and eastern counties. The root lesion nematode was the most widespread nematode found. SCN seed treatment field trials (including sites in Rodney and Highgate, Ontario) showed that environmental factors strongly impact treatment efficiency. No one seed treatment ranks higher in SCN management over all environments, but ILEVO did reduce SCN infection on roots more effectively than Saltro in most instances. The Ontario field trial data showed that nematicide seed treatments are most effective when used on an SCN-resistant variety. TURNING UP THE VOLUME Tenuta is the only Canadian representative on the SCN Coalition and has taken a leadership role in knowledge transfer activities, including organizing a successful National Soybean Nematode Conference in 2022. The partners reach 10,000 North American soybean growers per year through extension publications, field days, and presentations. The group has been recognized with numerous awards for excellence in marketing and promotions. “By increasing awareness, the active management by growers, as well as industry, is increasing in terms of looking at being the most effective at managing SCN with the tools that we have available to us right now, but also thinking about the future,” Tenuta says. The SCN Coalition recently developed the SCN Profit Checker calculator (thescncoalition.com/profitchecker) as a tool to help growers determine how much SCN is costing them in both yield and dollars. PRACTICAL RECOMMENDATIONS “What’s your Number? Take the Test. Beat the Pest.” is the tagline of the SCN Coalition. Eskandari and Tenuta recommend six steps for Ontario growers to plan an integrated SCN management action program. 1. Test fields to know SCN numbers 2. Rotate resistant varieties and different SCN resistance sources (including Peking) 3. Rotate non-host crops such as wheat and corn 4. Look for Sudden Death Syndrome (SDS) and other diseases 5. Consider a nematode-protectant seed treatment 6. Retest fields every four to six years to evaluate progress Additional resources are available at thescncoalition.com. This project was funded by Grain Farmers of Ontario and the Canadian Agricultural Partnership (CAP), a five-year federal-provincial-territorial initiative.