Research Brief

Diagnosing oak wilt with the naked eye

A leaf showing spots from oak wilt.
A leaf showing spots from oak wilt. Credit: Minnesota Invasive Terrestrial Plants and Pests Center.

University of Minnesota researchers developed a groundbreaking method for the rapid and accurate detection of oak wilt, a devastating disease threatening oak trees across North America. The disease is widespread in east-central and southeast Minnesota, though its range continues to expand northward, according to the DNR. Early detection methods are necessary in efforts to control the progression of this disease.

Recently published in Plant Methods, the research was funded by the University’s Minnesota Invasive Terrestrial Plants and Pests Center, supported by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources (LCCMR). 

The researchers created a diagnostic tool by incorporating gold nanoparticles into the Loop-mediated isothermal amplification (LAMP) assay. The LAMP assay is a desirable tool for field diagnostics because it is quick, reliable, low cost and requires minimal preparation. 

“This study introduces a novel approach that simplifies and speeds up the diagnosis of oak wilt, potentially transforming disease management practices for this serious threat to oak tree health in both natural and urban ecosystems in Minnesota,” said co-author Akli Zarouri, a researcher in the College of Food, Agricultural and Natural Resource Sciences.

They found: 

  • Gold nanoparticles react with the DNA molecules to create a distinct red pellet in the presence of the pathogen.
  • By using a naked eye detection, the tool provides results in 30 minutes.
  • The assay was rigorously tested on infected and healthy red oak samples, demonstrating exceptional sensitivity and specificity. It also proved effective with crude DNA extracts from diseased wood, streamlining the diagnostic process. 

“This LAMP assay, with its rapid processing and easy visualization, offers a powerful tool for field diagnosis of oak wilt, and holds potential for broader applications in plant pathology,” said lead author Vinni Thekkudan Novi, now a researcher at the USDA who completed this work as a graduate fellow in the U of M’s College of Food, Agricultural and Natural Resource Sciences. 

The researchers are in the process of field testing this technology so that it will be available for land managers in the near future.

Future research may focus on validating the LAMP assay under field conditions with a larger sample size to better represent oak wilt epidemiology and ensure consistent diagnostic sensitivity and specificity. Additionally, optimizing the assay for different environmental conditions for the visualization step could make it applicable and easier to use in various settings.

This research was also supported by the USDA National Institute of Food and Agriculture and the Schwan Food Company Graduate Fellowship.

About the College of Food, Agricultural and Natural Resource Sciences 
The University of Minnesota’s College of Food, Agricultural and Natural Resource Sciences strives to inspire minds, nourish people, and sustainably enhance the natural environment. CFANS has a legacy of innovation, bringing discoveries to life through science and educating the next generation of leaders. Every day, students, faculty, and researchers use science to address the grand challenges of the world today and in the future. CFANS offers an unparalleled expanse of experiential learning opportunities for students and the community, with 12 academic departments, 10 research and outreach centers across the state, the Minnesota Landscape Arboretum, the Bell Museum, and dozens of interdisciplinary centers. Learn more at cfans.umn.edu.

About the Minnesota Invasive Terrestrial Plants and Pests Center

The Minnesota Invasive Terrestrial Plants and Pests Center was founded by the Minnesota Legislature to research the prevention, detection and control of terrestrial invasive species. MITPPC researchers use transformative science to prevent and minimize the threats posed by land-based invasive plants, pathogens, and pests. Founded in 2015, MITPPC is the only research center of its kind in the country, and the center's work to protect the state's native prairies, forests, wetlands, and agricultural resources benefits all of Minnesota and beyond. Learn more at mitppc.umn.edu.

Media Contacts

Lori Fligge

College of Food, Agricultural and Natural Resource Sciences, Twin Cities
612-626-5457