Black locust leaves. Credit: Jan Samanek, Phytosanitary Administration, Bugwood.org, CC BY-NC 3.0 US, cropped for use.
Background
Black locust (Robinia pseudoacacia) is an aggressive invasive tree that threatens many different habitats in Minnesota, especially those that have historically supported oak savannah and prairie plant communities. Once established, black locust is difficult to manage due to its ability to develop new shoots from root collars and suckers, its pernicious thorns, and large size of mature trees.
Recent sightings of declining black locust stands suggest the presence of aggressive natural enemies. From these stands, researchers uncovered two canker fungi—which have been documented as serious pathogens of black locust in Europe—as well as other pathogens. Fungal pathogens collected during statewide surveys of dying buckthorn in Minnesota and Wisconsin may also prove to be lethal to black locust. Researchers aim to explore fungal biological control of black locust with mycoherbicides.
Research questions
- Where are other declining stands of black locust in Minnesota?
- What native fungal pathogens are associated with declining stands and cause cankers, wilts and root rots?
- What is the potential for these fungi to be used as mycoherbicide agents to control black locust?
- What are the most effective and accessible methods for successful field application of the mycoherbicide agents?
Practical implications
A successful mycoherbicide could be immediately implemented and become an important new tool that can be used by land managers to help control this serious invasive tree. By providing an effective treatment, it would slow or prevent the spread of black locust to the north and west areas of Minnesota where it is not currently found.
Findings
This project began in January 2026 and is in progress for the next several years. Please check back at a later time for updates.
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