New Yorkers Are Killing Spotted Lanternflies. Is It Working?

There are many ways to kill a spotted lanternfly.

One is the classic stomp: raising a foot high before hammering it into the sidewalk and hopefully flattening one of the distinctive bugs. Then there are the more standard insect-squishing techniques, such as the rolled-up magazine swat, the hand smack, the paper towel splat. Another is the shoe-swinging method, in which New Yorkers sacrificially tread barefoot on city streets so as to use their footwear as killing instruments.

The actor Kieran Culkin, known for his role as Roman Roy in “Succession,” was observed employing this tactic in Brooklyn last month, using one shoe to destroy, by his audible count, at least 70 lanternflies. One bystander declared him “a true N.Y.C. hero.”

People across all five boroughs have dutifully followed the city’s directive to kill the invasive insects on sight. But is it working?

So far this year, the bugs have been documented riding the subway, littering streets and even infiltrating apartments, evidence of a trend that experts anticipated: New York City’s lanternfly problem is getting worse.

While the grass-roots effort is not likely to significantly curb the lanternfly population, experts said, it can help raise public awareness of the problem while scientists seek a lasting solution. In short: Keep stomping.

Spotted lanternflies, native to Asia, were first identified in the United States in Pennsylvania in 2014. They have swarmed New York City every summer since 2020 and have become a nuisance across the Northeast, Mid-Atlantic and parts of the Midwest. While they pose no risk to humans, lanternflies can damage agricultural crops, particularly grapevines.

It’s difficult to estimate the number of spotted lanternflies in New York, because the city is not keeping an official tally of sightings or killings, said Chris Logue, who oversees plant industry at the New York State Department of Agriculture and Markets. But Mr. Logue said that lanternflies tend to be more noticeable toward the end of the summer because of their natural life cycle: Almost all the lanternflies that have hatched this year are now adults. Also, more of the insects are at eye level because they climb buildings, possibly looking for wind currents to ride, he said.

Brian Eshenaur, an entomologist at Cornell University, agreed that the population of lanternflies in New York City is much higher than it was last year.

“This is typical when the spotted lanternfly moves into a new location,” Mr. Eshenaur said. “The first couple of years, the populations build up, and then around year three they level off, and then often there is a drop in the population in future years.”

At first, officials urged members of the public to scrape lanternfly eggs — which can look like bark — off trees, Mr. Logue said. But that was far more labor intensive than simply squishing the bugs underfoot, so the city switched tactics.

Each female spotted lanternfly lays 30 to 60 eggs, Mr. Logue said, so the hope is that when people kill the lanternflies they come across, they can help mitigate the population growth.

But New Yorkers can only stomp so many invaders.

And Daniel Gilrein, another entomologist at Cornell, described the effect of New Yorkers’ lanternfly killing as “marginal,” saying there was little proof that isolated stomping was “having a desired significant impact on the lanternfly population.” But he noted that the communal effort “helps engage the public” and leads people to feel “somewhat empowered.”

The good news, Mr. Gilrein said, is that the city is currently contending with all the lanternflies it will see this year — only one generation hatches annually. The adults, recognizable by their two sets of wings — one pale gray with black spots, the other bright red — will stay active into October, laying eggs. Then the first hard freeze of winter will kill off all the adults, while the eggs will survive and new lanternflies will hatch next year.

“I expect lanternflies will be spreading into more areas and neighborhoods, establishing new populations that more will notice next summer,” Mr. Gilrein said.

Despite public perception, experts said the lanternflies were not becoming increasingly emboldened or skilled at dodging attempts to kill them. (Mr. Eshenaur said attacking the bugs head-on tends to be more effective than sneaking up from behind, since lanternflies usually launch forward when threatened.)

And while the increase in lanternflies has led to an increase in irritation, New York has so far been spared the agricultural damage that Pennsylvania experienced. Vintners in the Finger Lakes region and on Long Island have been on high alert since lanternflies attacked grapevines in Pennsylvania and reduced their yield, but said the bugs had not yet adversely affected New York’s wine industry.

“I think we have slowed the spread some,” Mr. Eshenaur said. “All of that time that we gained from a slower spread allows more research to take place, and there’s a lot that is happening now.”

According to Kareem Massoud, a winemaker at Paumanok Vineyards on Long Island, there have been reports of lanternflies outside the city, but the insects have yet to infiltrate the eastern portion of Suffolk County. Mr. Massoud said he was aware that the infestation could worsen, and likened it to witnessing “a slow motion train wreck.”

“You see it coming years in advance and, unfortunately, there’s not much we can do,” Mr. Massoud said.

Mr. Massoud said he was in close contact with experts at Cornell and Penn State, where the majority of the country’s lanternfly research is taking place. He has discussed the issue with growers in Pennsylvania, who told him that while lanternfly infestations are bad, they can be managed. Preventive measures include laying a fine mesh over the vines and spraying insecticides, both of which are seen as last resorts because they can also damage the crops themselves. Mr. Massoud also said he appreciated the actions of those who are killing as many lanternflies as they can.

“This is very much the sort of thing where we can enlist the public’s help,” Mr. Massoud said. “Kill it, squash it, capture it, report it.”

The U.S. Department of Agriculture is monitoring ports in an effort to limit the spread of lanternflies to other states or countries. People are also urged to check their cars, luggage and clothing when driving out of the city, Mr. Logue said, adding that lanternflies are “very, very good hitchhikers.”

Experts in Pennsylvania and New York are experimenting with larger-scale solutions, Mr. Logue said.

In higher-risk areas, officials have used special vacuums to suck up lanternflies. In the Bronx, which is experiencing a serious infestation, the New York Botanical Garden has removed plants that the insects are attracted to, said Vincent Galatolo, the garden’s director of plant health.

The Bronx Zoo hung triangular mesh traps engineered to catch lanternflies, said Sean Tarantino, the zoo’s horticulture supervisor. None of the zoo’s animals are interested in eating the invaders, Mr. Tarantino said. But entomologists in the Northeast are exploring introducing insects that naturally prey on lanternflies, although such a measure is years away from implementation, according to Mr. Logue. As time goes on, Mr. Eshenaur added, certain birds and predatory insects such as preying mantises and spiders are likely to figure out that spotted lanternflies can be a food source. Their developing palates could help keep the population in check, he said, but won’t eliminate the bugs.

Still, Mr. Logue said, New York needs its residents to continue the cull. Much is still unknown about the lanternflies and how best to get rid of them, so every action counts.

“Keep doing what you’re doing,” Mr. Logue said. “It’s a new surprise every day with the spotted lanternfly.”