DEC: Report oak trees losing leaves


RAY BROOK — Reporting oak trees that lose some or all of their leaves in July or August is the goal of a new oak wilt awareness campaign by the New York State Department of Environmental Conservation. 

DEC Commissioner Basil Seggos recently announced plans to manage the spread of the invasive species that causes oak wilt.

Oak wilt is a serious tree disease in the eastern United States, killing thousands of oaks each year in forests, woodlots, and home landscapes.

Oak wilt is caused by a fungus, Ceratocystis fagacearum, which grows in the water conducting vessels of host trees, plugging up these vessels and preventing water transport.

As water movement within the tree is slowed, the leaves wilt and drop off.


Seggos confirmed that the 15 trees infected by oak wilt in New York during 2016 have been removed.

DEC is encouraging the public to be on the lookout this summer for oak trees that suddenly lose all or most of their leaves during the months of July or August.

These occurrences should be reported to DEC’s Forest Health Information Line toll-free at 1-866-640-0652, or via email

Submitting pictures of oaks showing symptoms of oak wilt is highly encouraged.


DEC is continuing to monitor for additional infection sites in cooperation with state and local partners, including the Plant Disease Diagnostic Clinic (PDCC) at Cornell University, and the New York State Department of Agriculture and Markets (DAM.)

“Without the support of the Department of Agriculture and Markets and Cornell University, these oak wilt infections may have gone unnoticed and the potential for spreading throughout New York State could have led to a significant loss of oak trees,” said DEC Commissioner Basil Seggos.

“Continued collaboration with our state and local partners is critical to protecting our rural and community forests.”

DEC identified potential infection sites, collected samples, and submitted them to Cornell University for analysis.

Cornell’s PDDC staff conducted tests to confirm or rule out the presence of oak wilt.

The funding for this work was provided by DAM through the Specialty Crop Block Grant Program.

PDDC will continue to test submitted samples throughout the 2017 growing season while working to streamline and testing procedures.


DEC is dedicating four additional staff to oak wilt this summer.

Crews will monitor trees in the protective zones near infection centers and watch for oak wilt symptoms to track the spread of oak wilt in the areas where it was detected last year.

DEC will also be conducting aerial surveys in July and September over the protective zones, in the lower Hudson Valley, and the Southern Tier to look for symptomatic trees.

DEC staff will visit symptomatic trees detected in aerial surveys and by landowners to determine if a sample should be taken. DEC plans to take 200 oak wilt samples this year, which will be sent to Cornell for processing.

DEC is also working with partners to plan a public oak wilt symposium for this fall.


Governor Cuomo increased funding for invasive species control to $12 million from the Environmental Protection Fund in the 2017-18 State Budget, including a $2 million grant program for communities and groups across New York.

Invasive species are detrimental because of their ability to reproduce quickly, outcompete native species, and adapt to new environments.

Because invasive species did not evolve with the other species in their new location, they often do not have natural predators and diseases that would normally control their population within their native habitat.

Economists estimate that invasive species cost the United States more than $120 billion in damages every year.

For more information about oak wilt or the emergency orders, visit DEC’s website at


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