Seed coating with plant-derived lipid biosynthetic and metabolic inhibitors protects soybean plants infected by seed-borne Cercospora cf. flagellaris. Soybean plants grown from seeds with Cercospora cf. flagellaris inoculation. Photos provided by Chien-Yu Huang

As fungal diseases continue to challenge soybean production, researchers are working to develop new tools that help growers protect yields while reducing reliance on traditional fungicides. At the LSU AgCenter, Chien-Yu Huang, assistant professor in the Department of Plant Pathology and Crop Physiology, is leading a project aimed at developing plant-derived treatments to control major soybean diseases, including Cercospora leaf blight, frogeye leaf spot and aerial blight.

The three-year study is now entering into its second year and has already produced encouraging results.

The project focuses on naturally derived compounds that may provide a safer and more environmentally friendly alternative to conventional fungicides. According to Huang, the first year of the project centered primarily on seed treatments, which offer the advantage of protecting plants from disease with a single application.

Many soybean pathogens originate from infected seeds or pathogens that survive in the soil, making seed treatments an important first line of defense.

Huang and her research team evaluated many plant-derived compounds through laboratory testing, examining seed germination, emergence rates and disease severity. They observed promising results from some of the treatments, indicating their potential to suppress disease while maintaining healthy plant development.

Early foliar treatment studies were evaluating how these compounds might perform when applied directly to plant leaves.

“The first year we have collected some data really supporting some of our formulas for seed treatments, so this year so far we are focused on that,” Huang said.

Building on the success of the first year, Huang and her research team are now moving from laboratory studies into field evaluation. This growing season marks the project’s first field trial at the LSU AgCenter Doyle Chambers Central Research Station.

Based on first year lab results, Huang selected the most promising seed treatment formulations for field evaluation and will allow researchers to evaluate treatment performance under real-world growing conditions. The study includes three replicated plots to ensure accurate and reliable results.

Moving forward with the project into year three, Huang hopes to expand field trials across Louisiana to determine how the treatments perform under a range of environmental conditions and weather patterns. She understands the unique challenges that replicating field trials in Louisiana faces.

“Recently this year we had to push a little bit because it’s raining a lot this year, so our planting season, got a bit delayed for one or two weeks,” she said.

To advance the project into field testing, Huang partnered with Sara Thomas-Sharma, assistant professor in the Department of Plant Pathology and Crop Physiology, who designed the field experiment and oversees field management practices.

Huang also mentors graduate students who conduct laboratory testing, culture fungal pathogens and assist with field observations throughout the growing season.

The research addresses both primary and secondary sources of disease infection. Seed treatments are intended to prevent primary inoculum, pathogens carried on soybean seeds, while future foliar treatments could help control secondary inoculum spread from infected plants in the field. Huang is continuing to evaluate how long the plant-derived compounds remain effective under field conditions and how they may be incorporated into future disease management programs.

Ultimately, the goal is to develop a new disease-management product that is both effective and sustainable. Because the compounds being studied are derived from plants and many already have available safety information, they may offer an easier path toward regulatory approval while providing an eco-friendly alternative to conventional fungicides. Early results suggest it could become a valuable new option for soybean producers seeking effective ways to manage disease pressure and protect crop yields.

“There are several issues when we use fungicides to control fungal diseases, including fungicide resistance and concerns about synthetic fungicide safety,” Huang said. “We are trying to give growers another tool they can use in their toolbox.”

As the project advances from the laboratory to the field, Huang and her team remain focused on delivering practical solutions to future challenges.

Madaleine Alessi and Indira Poudel, graduate students in the Huang group, started the field trial for the 2026 growing season by using plant-derived molecules against Cercospora leaf blight.