Postdoctoral associate Jyoti Saini Sharma inspects common buckthorn for crown rust, photo provided by Pablo Olivera Firpo
Background
Common buckthorn (Rhamnus cathartica) is a highly invasive plant that is well-established across Minnesota. It disrupts ecosystems and degrades wildlife-supporting habitats by outcompeting and displacing native vegetation. Buckthorn is difficult and costly to eradicate, requiring long-term commitment from land managers.
Several crown rust fungi (Puccinia Series coronata) have been found to infect and negatively affect common buckthorn. Building on their prior research on rusts of glossy buckthorn, this project team will identify the specific crown rust fungi that infect common buckthorn in Minnesota, determine the symptoms of disease, and document the host range of the pathogen. Once identified, they’ll evaluate the pathogen’s effects on common buckthorn including growth and mortality.
Research questions
- What are the crown rust fungi that infect common buckthorn in Minnesota?
- What is the host range of the pathogen species in common buckthorn and graminoids?
- What are the disease symptoms and severity of the pathogen species?
- What is the effect of the pathogen on common buckthorn seedlings?
Outcomes
Over a two-year statewide survey of rust-infected buckthorn, researchers found that one crown rust species, Puccinia coronati-brevispora (Pc-b), was by far the most common, accounting for more than 80% of all samples collected. This same rust also infects smooth brome, one of Minnesota's most widespread invasive grasses. Three other crown rust species were detected, including the species that infects oats, but they occurred much less frequently.
The team's field studies showed that exposing young buckthorn seedlings to rust-infected (Pc-b) smooth brome straw greatly reduced their growth and survival. Additional experiments showed that crown rust also significantly reduced the growth and recovery of smooth brome and Kentucky bluegrass.
Overall, these results show that Pc-b can greatly reduce the growth and survival of both common buckthorn and smooth brome. This suggests it could become a valuable natural tool to help manage these invasive species as part of an integrated management approach.
Outreach
- American Phytopathological Society Plant Health Conference, 2024
- Upper Midwest Invasive Species Conference, 2024
- CFANS Research Symposium, 2026
News and media
- Fighting buckthorn with fungi - MITPPC
- U researchers hopeful for naturally-occurring end to invasive buckthorn - CBS WCCO
- Scientists think a fungus could conquer invasive buckthorn - Star Tribune
- Beating the buckthorn blues - UMN News
- Submit field observations of diseased or dying buckthorn - MITPPC
- Meet Jyoti Saini Sharma: A seasoned plant pathologist exploring rust fungi to control buckthorn and invasive grasses - MITPPC