Science

Spotted Lanternflies Take On the Big Apple

Though they are not directly dangerous to humans—they’re not poisonous, they don’t sting and they don’t bite—they do drain the economy, impoverish our trees, and are, to state it simply, annoying. So the question remains: what can you do to rid New York City of lanternflies?

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By Geoffrey Huang

The short walk to Ferry’s with a freshly cooked bacon-avocado-chipotle sandwich in hand from the Tribeca Bridge’s left entrance is not an uncommon practice at Stuyvesant. However, since earlier this year, there has been a tweak to this usual tradition: the walk now induces Stuyvesant students to become vigilante exterminators. What was once a solid concrete pavement outside Ferry’s has now become a red, speckled graveyard.

If you’ve never seen the Ferry’s graveyard, you may have seen these red bugs in the viral video of them swarming the Nomad Tower on 32nd Street and Broadway, or a peculiar one hiking to the 31st floor window of a Manhattan skyscraper in search of a mate, or even the satisfying TikToks of people vacuuming hoards of them off terraces, cars, and trees all across the five boroughs. Lycorma delicatula, more notoriously known as the spotted lanternfly, is native to China. It was first detected in the United States in September of 2014 when a stone shipment from China, inadvertently carrying lanternfly egg masses, was brought to Pennsylvania. Infestations have since spread across Pennsylvania, New Jersey, Long Island, the Hudson Valley, and in July of 2021, the Big Apple.

The inch-long invasive organisms have attractive polka-dotted wings and bright red hindwings that are highly visible when the lanternfly is in flight or when its wings are open. They’re planthoppers, which constitutes for their speed and ability to fly short distances—though they primarily jump long distances.

They owe their dominion to the absence of natural predators in the United States. The few predators that do exist in the areas they invade, including stink bugs and wheel bugs, are unable to control the situation because their main diet does not consist of lanternflies. Apart from environmental factors, lanternflies are naturally fertile and lay millions of egg masses in late summer on the trunks of trees and any other smooth surface. The portable items that they lay their eggs on, such as vehicles and outdoor furniture, can easily be unintentionally transported by humans, conveniently dispersing the species across the US. Because the hoppers crawl to nearby host plants and start new infestations upon hatching, they’re able to dominate areas rapidly.

The hoppers feed by piercing the bark of trees to tap into their vascular systems in search of sap. Due to their relatively large size in comparison to most sucking insects, they’re able to remove large amounts of sap while excreting a thick, sticky dew that coats the tree. The dew doesn’t directly harm the tree, but the loss of carbohydrates and other nutrients meant for storage substantially slows growth and eventually leads to the tree's death.

According to the New York State Department of Agriculture, the lanternflies are a threat to native New York plants and crops including grapevines, apple trees, and maple trees. With a diverse palate that could feed off of over 70 plant species, they pose a significant threat to New York’s agriculture and forest health.

Though they are not directly dangerous to humans since they’re not poisonous, don’t sting, and don’t bite, they do drain the economy, impoverish our trees, and are a general nuisance. New York’s annual yield of apples and grapes yields a net profit of $358.4 million, which the spotted lanternfly’s cravings for apple trees and grape vines can adversely affect. As of now, the full extent of economic damage—ranging from property damage costs to revenue and farm loss—is unknown but is expected to range between a drain of $1.3 billion annually and a loss of about 2,800 jobs. So, the question remains: what can you do to rid the Big Apple of lanternflies?

For starters, you can go with the traditional “Spot and Stomp” method. This is the formal course of action recommended by the New York Department of Agriculture and Markets (DAM): “If you see a lone Spotted Lanternfly in New York City, kill it immediately by stepping on it or crushing it.” You can’t really go wrong with this one—if you miss the first time, just try again (they can’t jump very far without running out of energy).

You can also attack the problem at its roots by searching for and destroying lanternfly eggs, which are the main source of their spread. The insects will typically lay their eggs from September to early December, meaning it won’t be rare to spot eggs in NYC right now. They typically lay egg masses containing 50 eggs, each about one millimeter in diameter. The eggs are laid on smooth surfaces, including bricks, lawn furniture, play structures, fences, and more, and resemble dried patches of white to dull brown mud. If found, the best way to destroy the eggs is to scrape them off the surface with a plastic card and squash or drop them in hand sanitizer.

Though they lack traditional predators, the hoppers are still susceptible to handy-dandy chemical insecticidal sprays. This would be the best method if you find large clusters of spotted lanternflies in your backyard. However, alternatives to chemical sprays include more environmentally-friendly organic insecticides. Examples of such pesticides include Ortho Elementals Insecticidal Soap and Safer Insect-Killing-Soap.

Another option for those who would rather save themselves from bug guts is to catch them in an empty bottle. Simply point the opening of an empty bottle toward the bug and approach it from above. Once you’re close enough, the lanternfly will get startled and instinctively jump inside since jumping is their natural flight response. This method is effective because you can capture a large number of hoppers with a single bottle. Don’t forget to dispose of them after though, preferably and most effectively by placing the bottle in a freezer overnight.

Earlier this year, in response to the invasion, Senator Chuck Schumer called for $22 million more in funding to the US Department of Agriculture to target the invasive species. Of course, New York State does not plan on relying on its citizens as vigilante exterminators forever, but for now, having people kill lanternflies is an effective short-term solution. Scientists will continue to battle the planthopper’s reproductive clock until they develop long-term, sustainable fixes to win back the Big Apple.