Asian longhorned beetle alert: Be on the lookout for these tree-killing insects

Long Islanders are being asked to keep an eye out for the voracious Asian longhorned beetle, known for its ability to kill more than one dozen types of North American hardwood trees.

The U.S. Department of Agriculture said August is a key month for keeping this invasive pest in check because that is when people are most likely to see adult beetles. 

About 53 square miles of central Long Island straddling the Nassau and Suffolk border is the only current quarantine area in New York, as officials try to keep the beetle in a contained area. It has been eradicated in previous quarantine areas in New York City as well as in Islip.

“We are asking that people check their trees, and trees in their communities, for the beetle and the damage it causes,” said Rhonda Santos, public information officer at the USDA’s Asian Longhorned Beetle and Emerald Ash Borer programs.

“This is important if they live in the quarantined area since that is where we know the beetle is,” she said in an email. “But it’s also important in the communities surrounding the quarantine since the beetle can move on its own or be moved unknowingly by people." 

The shiny, black, white-spotted insects are between 1 and 1½ inches long and have antennae that surpass their body length. The damage they inflict on trees is extensive, creating, in their larval stage, tunnels in trunks and branches. When they emerge as adults, the beetles leave holes and then devour the leaves and bark.

Once the trees are infested, they will never recover, according to the USDA. Damaged trees pose hazards, especially during storms when they can be knocked over. The insects were first spotted in the U.S. in Brooklyn in 1996.

The USDA said 2,892 trees infested with the Asian longhorned beetle were found in the area roughly bounded by parts of Massapequa to West Babylon on the South Shore and up to the Long Island Expressway on the north. An exact map is available on the New York State Department of Agriculture and Markets website.

Movement of wood and trees is strictly regulated in quarantine areas to prevent further spread of the beetle.

“It is certainly something we continue to watch for and remain aware of, and I continue to remind arborists and others at our winter meetings to be on lookout for it, or for suspicious signs such as the very round exit holes — a pencil fits easily inside — on broadleaf trees like maples, elm and some others which have been heavily attacked,” said Dan Gilrein, an entomologist and associate agricultural program director at Cornell Cooperative Extension of Suffolk County. “I forward any suspicious reports to the NYS ALB Eradication Program staff.”

People who believe they have found either an Asian longhorned beetle or a tree damaged by it are urged to take a photograph to document it and call the ALB hotline at 866-702-9938 or file an online report at asianlonghornedbeetle.com.

If possible, capture the beetle in a container and freeze it for identification purposes, the USDA recommends.

By Lisa L. Colangelo

lisa.colangelo@newsday.com@lisalcolangelo

Lisa joined Newsday as a staff writer in 2019. She previously worked at amNewYork, the New York Daily News and the Asbury Park Press covering politics, government and general assignment.