Brazilian scientists have identified soil fungi from the Trichoderma genus capable of completely eliminating Sclerotinia sclerotiorum sclerotia — the survival structures of the fungus responsible for white mold, a major threat to crops like soybeans, beans, and cotton. The findings, developed in a laboratory setting, open new doors for biological control of a disease typically managed with costly and environmentally harmful chemical fungicides.
The study, led by Laísy Bertanha of São Paulo State University (Unesp) under the guidance of Embrapa researcher Wagner Bettiol, pinpointed strains of Trichoderma yunnanense and Trichoderma dorotheae that inhibit up to 100% of pathogen germination. T. yunnanense stood out with a 97.5% success rate, highlighting its promise as a biofungicide.
A Sustainable Alternative to Chemicals
White mold is notoriously difficult to manage due to the longevity of its sclerotia in the soil. Traditional control relies on intensive fungicide use, which carries high costs, environmental risks, and the potential to drive fungicide resistance. Trichoderma-based biocontrol offers a safer, more sustainable alternative, according to a press release.
The research shows that combining different Trichoderma strains can enhance disease suppression, especially when sourced from the same environment where they’ll be applied. This approach boosts their ability to adapt and target specific pathogens.
Part of Integrated Disease Management
As part of the growing biopesticide movement in Brazil, this study reinforces the role of biocontrol in integrated disease management (IDM). Bettiol notes that although Trichoderma has been used in Brazil since the 1980s, challenges remain in scaling production, integrating it with conventional practices, and ensuring farmer adoption.
Effective IDM should pair biocontrol with other strategies, such as:
- Crop rotation, especially with grasses that are non-hosts of Sclerotinia
- Increased organic matter to boost beneficial microbes
- Use of pathogen-free seeds and machinery sanitization to prevent fungal spread
- Because white mold is monocyclic, the initial presence of inoculum has a major impact on disease severity—making these preventive practices crucial.
Beyond Control: Reducing Virulence
The study also found that Trichoderma strains reduce the aggressiveness of white mold by interfering with the pathogen’s ability to produce oxalic acid, a key compound in its infection process. Among nine Trichoderma species isolated from organic farming soils, T. yunnanense and T. atrobrunneum showed strong disease suppression.
Isolated from irrigated bean fields, T. yunnanense exemplifies how local microbial diversity plays a critical role in soil health and pathogen suppression. This underscores biocontrol’s potential to foster more resilient, balanced agricultural systems.
The effectiveness of biocontrol depends on the adoption of integrated strategies, combining biofungicides, cultural practices and, when necessary, chemicals. “This approach allows a more efficient management of white mold, reducing environmental impacts and promoting more sustainable agriculture,” concludes Bettiol.
