Oak Wilt Detected in Canandaigua

The New York State Department of Environmental Conservation (DEC) announced today that oak wilt, a tree fungus that causes disease in oak trees, has been detected in Canandaigua, Ontario County.

This is the third location in New York State where oak wilt has been confirmed and the second location discovered in 2016. The disease was confirmed in Islip earlier this year and had previously been found in Glenville in 2008 and 2013.

"If left untreated, oak wilt is a serious disease that can quickly spread and kill oak trees," said DEC Commissioner Basil Seggos. "New York State is taking the detection of oak wilt in Canandaigua seriously and has already begun implementing survey and control procedures recently used in Schenectady and Suffolk counties to contain and treat the oak wilt infestation found in Canandaigua."

A concerned homeowner contacted Cornell Cooperative Extension after an oak tree on their property began dying with no identifiable cause. Samples from the tree were sent to the Cornell Plant Disease Diagnostic Clinic, where they tested positive for the fungus that causes the disease. There is no known treatment to contain and kill the oak wilt fungus other than to remove infected trees, as well as any surrounding host oak trees.

An emergency order will be issued establishing a protective zone prohibiting the movement of oak material out of the immediate area to prevent the fungus from spreading. Aerial and ground surveys will be conducted during the next few weeks to identify additional trees that may be infected. DEC staff will contact property owners near the infected oaks to inform them about oak wilt and request permission to examine oaks on their properties for signs of the disease.

Since the infested tree was discovered late in the growing season, only a small window exists to look for signs of the disease before the natural loss of leaves during the fall makes it too difficult. Infected trees will be removed during the winter months; surveys will resume in the spring when dead trees and signs of the fungus are more apparent.

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 the fungus, Ceratocystis fagacearum, which grows in the water-conducting vessels of host trees, causing the vessels to produce gummy plugs that prevent water transport. As water movement within the tree is slowed, the leaves wilt and drop off, and eventually the tree dies.

DEC asks the public to report any occurrences where an oak tree died over a short period of time, especially if it occurred between July and August, to the Forest Health Information Line toll-free at 1-866-640-0652.

For more information about oak wilt, please visit DEC's website.