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Oak Wilt Analysis

The Cornell Plant Disease Diagnostic Clinic (PDDC), in conjunction with the New York State Department of Environmental Conservation (NYS DEC) and the New York State Department of Agriculture and Markets (NYS DAM) has been surveying trees across New York State (NYS) for the plant pathogen, Bretziella fagacearum (formerly Ceratocystis fagacearum). This fungus causes a devastating disease known as Oak Wilt that may kill highly susceptible trees such as members of the red oak family, within the same season that symptoms develop.

Because this potentially devastating pathogen had been identified twice in one upstate NY community within a period of 6 years, we felt a broader investigation was needed. Searching potentially favorable sites for the oak wilt pathogen could help to identify areas where the pathogen may be present early enough for management efforts to be more effective. Sampling began in June 2015 and continued through mid-October 2018.

This project was intended to help us get a better understanding of the general health of red oak trees across the state and identify locations throughout the state where additional eradication efforts are needed. Plant pathologists and other green industry specialists that work with tree health have learned through numerous case studies that the earlier an infection is found, the greater the chances are for successful eradication.

As a result of this project, the pathogen has been detected in additional areas. For more information, please see the sections below regarding the 2016 and 2017 finds.    

2016 Oak Wilt Findings

Cornellís Plant Disease Diagnostic Clinic Identifies the Pathogen that causes Oak Wilt on Long Island

On August 2, 2016, the NYSDEC announced that we identified the oak wilt pathogen at a new location, the second in New York State. The pathogen was found on trees from Central Islip on Long Island. The trees were submitted to the Plant Disease Diagnostic Clinic after a concerned arborist had ruled out a number of common diseases and disorders. He had seen some of the informational materials we distributed, specifically the BOLO-Be On the Look Out postcards and he decided to send samples to the Clinic just to make sure he was covering all the bases.

We are thankful to all of the individuals who have diligently pursued answers for the decline of oak trees in these locations.

None of this work could have been done without the support of a Specialty Crop Block Grant and without this project, we may not have found this new site in an early infection stage which is key for successful eradication efforts. The grant allowed us to develop and distribute the informational marketing materials and it gave us the resources needed to develop and test additional identification methods that we hoped would help us identify the pathogen more quickly and by using different types of testing methods.

See the links in the column to the left of materials provided for information about symptoms to look for, who to contact if symptoms are found, and if found on your property, how to submit a sample for processing. See the NYS-DEC press release regarding this at:

Cornellís Plant Disease Diagnostic Clinic Identifies the Pathogen that causes Oak Wilt in Canandaigua, NY.

On October 25, 2016, NYSDEC announced that the oak wilt pathogen had been identified at a third location in New York State, the second new location this year. This identification follows from a concerned homeowner contacting Cornell Cooperative Extension, with subsequent submission of a suitable sample to the Plant Disease Diagnostic Clinic for analysis. For more information, please see the NYS-DEC press release regarding the Oak Wilt find on Long Island at: Additional information may also be found on the NYS-DEC website at:

2017 Oak Wilt Findings

New Oak Wilt Locations Found in Glenville

On 12-12-17, NYSDEC announced the discovery of two new oak wilt locations in Glenville NY. Glenville was the site of the first find in New York State back in 2008. These two new Glenville identifications were the only positive finds made in New York in 2017. This article describes the new locations and the steps they are taking to eradicate the pathogen:

The Cornell Plant Disease Diagnostic Clinic staff performed the sample testing for the NYSDEC 2017 Survey. These two new finds were were the only positive finds from 143 samples processed by the PDDC in 2017. The first positive was found in the Sanders Preserve, approximately 3 miles east of the original oak wilt site and the second positive was found at a residence around 7 miles to the Northwest of the original site.

2018 Oak Wilt Updates

To stay up to date on the 2018 survey, please visit the NYSDEC Oak Wilt webpage to view their Quarterly Reports for 2018.

NY News Daily Article on Oak Wilt in Brooklyn
WCBS Channel 2 News Inteview about Oak Wilt
Associated Press on oak wilt
Cornell Chronical Article on finding oak wilt in 6 new locations.
Sample Submission Instructions and Form for Regulatory Staff & Surveys
Sample Submission Instructions and Form for General Sample Submission
New 2017 Oak Wilt Poster
Oak Wilt Postcard
Oak Wilt Assessment by G. W. Hudler (2008)
YouTube Video by G. W. Hudler (2008)
Additional References and Publications