The New York State Department of Environmental Conservation (DEC) has expanded the oak wilt quarantine district in response to new infections found in Yates and Ontario counties. The newly established district now covers all of Middlesex, Italy, and South Bristol, as well as portions of Bristol and Naples. This action is intended to prevent the spread of oak wilt by restricting the movement of oak wood from the affected area while treatment and monitoring efforts continue.
“Oak wilt can have a devastating impact on private and state lands,” said DEC Commissioner Amanda Lefton. “Expanding the quarantine district in the Finger Lakes is a necessary step to stop the spread of this destructive disease and protect the long-term health of our forests. Oak trees are an important part of our environment and local economies, and DEC is committed to working with communities, landowners, and industry partners to safeguard these vital resources.”
Aerial surveys conducted by DEC in July 2025 identified discolored oak trees. Subsequent testing by Cornell University’s Plant Disease Diagnostic Clinic confirmed oak wilt at seven sites across Middlesex, Italy, South Bristol, and Naples—four on private properties and three within DEC’s High Tor Wildlife Management Area.
To contain the outbreak, DEC removed infected oaks along with some nearby healthy-appearing trees as a precaution. Stumps were treated with herbicide to destroy roots, while logs and branches were either chipped or burned to eliminate fungal spore mats that facilitate disease spread. Monitoring will continue for stump resprouting or symptoms in neighboring oaks for at least five years through aerial surveys.
Under current restrictions, moving oak logs or branch debris out of the quarantine district is not allowed unless material is chipped smaller than one inch in two dimensions. Non-oak wood must be transported only if it measures at least 29 inches long for identification purposes. Limited Transportation Permits are available during fall and winter for moving oak wood products outside the district boundaries. A map outlining these areas can be accessed via DEC’s website.
Meanwhile, DEC has lifted its quarantine order for Glenville in Schenectady County after no new infections were detected since 2018. Oak wilt was first identified there in 2008; since then, more than 200 oaks across 23 properties had been removed as part of containment measures. Ongoing surveillance will continue for signs of recurrence.
Oak wilt was initially discovered in Wisconsin in 1944 before spreading widely throughout parts of North America where it continues to kill thousands of oaks annually. The disease results from infection by Bretziella fagacearum fungus which clogs tree vessels responsible for water transport—leading quickly to leaf loss and death especially among red oaks. Transmission occurs through root connections between trees or via beetles carrying spores from infected wood; firewood movement also plays a role.
Further information about regulations or assistance can be obtained from DEC’s official website or local offices.
