Executive Summary:
A novel sampling method that uses petioles from fallen leaves is non-destructive and highly accurate for detecting Bretziella fagacearum, the fungus that causes oak wilt, using real-time PCR and culture-based methods.
Background:
Bretziella fagacearum has been distributed to much of the Midwest and Southern United States and is responsible for the disease known as oak wilt. It kills 100% of the trees it infects and is spread either via root systems or from beetles that can carry the pathogen spores from one tree to the next. Traditional laboratory testing methods involve destructive sampling of either a fresh branch with leaves at least 6 inches long (including sapwood) or a fresh sample of the sapwood from the trunk.
Description of Technology:
This invention is a novel method to detect Bretziella fagacearum within a tree less invasively. While it still requires an off-site laboratory, it replaces the need for an entire fresh sapwood sample with just a leaf petiole. This significantly reduces harm to the tree and labor, tools, and expertise needed to collect larger, discolored sapwood samples. The method is not limited to fresh petioles and has shown accurate results even in older ones.
Drs. Miles and Chahal developed this sampling method, which can be coupled with their optimized and validated TaqMan PCR assay or traditional culturing methods to detect the pathogen. Sample preparation time has dropped from about 10-12 minutes to 1-2 minutes per sample. It has proven effective across varying disease severities and tree hosts, enhances high-throughput screening, especially in greenhouse seedling experiments, and offers a new solution for detecting B. fagacearum in non-lignified plants.
Key Benefits:
Quicker and less labor and experience needed for sampling (leaf petiole), with highly accurate readings
Samples do not need to be fresh, no need to confirm sapwood discoloration
Faster sample preparation time, screening of greenhouse seedlings possible
Applications: Fast and effective Bretziella fagacearum (oak wilt) testing
Inventors: Timothy Miles, Karandeep Singh Chahal
Related Publications:
Miles, L., Marcy, R. D., & Chahal, K. (2024, September 10). New MSU research puts oak wilt testing within reach of homeowners. Michigan State University Extension. https://www.canr.msu.edu/news/new-research-puts-oak-wilt-testing-within-reach-of-homeowners
Chahal K, Wachendorf EJ, Miles LA, Grove AM, Chilvers MI and Miles TD, 2025. Novel non-destructive detection methods for Bretziella fagacearum in northern red oak and chestnut. Phytopathology. https://apsjournals.apsnet.org/doi/10.1094/PHYTO-08-24-0253-R
Licensing Rights and Collaboration Opportunities Available
Please contact Julia Miller at 517-884-0721 or mill2034@msu.edu for testing, licensing, and sponsored research inquiries.
