Oak wilt disease found in Central Islip, officials say

A devastating disease that restricts water use in oak trees has been found in Central Islip, two state agencies said.

Oak wilt was identified in the trees by the Cornell Plant Disease Diagnostic Clinic after samples from a symptomatic oak tree were submitted by a concerned tree-care professional, the Department of Environmental Conservation and the Department of Agriculture and Markets said Tuesday.

It’s the second confirmation of the disease in New York State. Previously, diseased trees were identified and removed in upstate Schenectady County in 2008 and 2013.

After the provided oak samples in Central Islip tested positive, the tree-care professional removed and destroyed the four trees that exhibited signs of being infected, according to a news release.

Both agencies said there is no known treatment to contain and kill oak wilt fungus, other than removing the infected trees as well as any surrounding host oak trees.

“The infestation is small and isolated making an aggressive eradication response warranted and feasible to address this serious disease,” Basil Seggos, commissioner of the DEC, said. “Additional oak trees will need to be removed in the immediate infected area to stop oak wilt in its tracks.”

The DEC said it will use eradication protocols from the Schenectady County situation to control the Islip infestation.

“An emergency order has been issued establishing a protective zone that prohibits the removal of any living, dead, standing, cut or fallen oak trees or any portion thereof, including branches, logs, stumps or roots, green oak lumber and firewood (of any species) out of the immediate area unless it has been chipped to less than one inch in two dimensions,” the agency said in the release.

The order also establishes a 150-foot “red oak free zone” around the area where the infected trees were discovered.

All red oak in these zones will be removed by DEC and destroyed to protect the remaining oak trees in the area, the DEC said.

The release said property owners will be contacted about the about oak wilt, including how to help protect their remaining oak trees.

Also, the agency will schedule a public meeting to address questions and concerns. Aerial surveys, as well as ground surveys, will be conducted to determine the number of trees that need to be removed from the red oak free zone; tree removal is expected to take place within the next six months, the DEC said.

Oak wilt kills thousands of oaks each year in forests, woodlots and home landscapes, primarily in the eastern United States, the release said.

It is caused by a fungus that grows in the water-conducting vessels of host trees and causes the vessels to produce gummy plugs that prevent water transport. As water movement within the tree is slowed, the leaves wilt and drop, and eventually the tree dies.

Residents can report any sudden leaf loss from oak trees — a sign the disease could be present — by calling 866-640-0652. More information is at the DEC website: dec.ny.gov/press/press.html.