The state Department of Environmental Conservation is asking pool owners to participate in its annual survey to help safeguard the environment against the threat of Asian longhorned beetles.

The survey is part of a six-year research effort to eradicate the beetles, according to a DEC news release. The agency is warning pool owners to check their pool filters periodically for the insects. The purpose of the survey is to track the beetles’ movements. Once they are spotted in certain pools, officials can check the surrounding trees for possible infestation, said DEC spokeswoman Lori Severino.

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The agency said the beetles, which are native to China and Korea, have been damaging trees and forests in the boroughs of Manhattan, Queens and Staten Island, and in Islip and central Long Island since 1996. Most of the insects were eradicated by 2013, but in parts of Amityville, Queens and Brooklyn, they still pose a threat, according to the DEC website.

The DEC is also asking the public to be on the lookout for signs of the beetle’s presence in trees, such as perfectly circular dime-size holes; deep exit holes that can fit a No. 2 pencil; half-inch depressions that act as egg-laying sites with or without sap oozing from them; and sawdust or frass, a fine, powdery sawdust-like byproduct, at the base of a tree or tree branches.

Nick Bates, an urban forestry educator at Cornell Cooperative Extension of Nassau County, has been a part of the replanting effort to replace trees damaged by the insects.

“The biggest concern is hazard trees,” said Bates, referring to trees that have been so damaged by the beetle infestation that they become fragile and can barely stand. “They bore large holes in the trees and cause branches or a tree to fall.”

The DEC is asking residents to take pictures of the beetles they spot and send the images to the Forest Health Program at foresthealth@dec.ny.gov, or mail the beetles to the DEC’s Forest Health Diagnostics Lab for identification, at 108 Game Farm Rd., Delmar, NY 12054.