The Year of the Spotted Lanternfly

I was sitting in a New Jersey Transit train at Bay Street Station in Montclair, New Jersey, one afternoon when I saw a spotted lanternfly. The station’s eastbound and westbound tracks are divided by a chain-link fence about five feet high, probably to keep people from crossing them. In the double-decker cars, the bottom tier of seats puts you at eye level with the train platform, and, when you look out the window at the stations, you see the passengers’ shoes. I happened to be on the left side of the train, where the view was of the top bar of the chain-link fence, closeup. As I watched, a spotted lanternfly walked along the top of the fence.

Each section of fence is supported by a vertical pipelike pole with a hemispheric metal cap. The spotted lanternfly got to the pole and went up the inch or two at the top slowly, each pair of its legs at a time; then it walked a careful semicircle as it traversed the cap. It descended on the other side of the cap, stepped six-leggedly onto the top bar of the next fence section, and continued onward. Spotted lanternflies have a set of hind wings, half of which are bright red, the color of Certainly Red lipstick. When the insect is at rest, the dull brown forewings cover the hind wings, and you can’t see much of the red. As this bug maneuvered itself onto the cap, for a moment the wings flared and the red showed vividly.

Had it ridden here on the train? It might have. Suddenly, spotted lanternflies are all over the place. State agricultural-experiment stations have put out warnings about how they ride on cars and trucks (though the warnings don’t appear to include trains). The bugs even lay eggs in your car’s wheel wells. You may think that an egg patch is just some dried mud that has caked there. Adult insects hold on to vehicle surfaces tenaciously. I think maybe because they have sticky feet.

At a booth at the Nutley, New Jersey, farmers’ market, volunteers from the Rutgers University Master Gardeners program tell people that spotted lanternflies (formally known as Lycorma delicatula) are plant-hoppers and come from Asia. Why they suddenly blew up in population in the New York–New Jersey–Pennsylvania area this year is a mystery; they were first found in Pennsylvania’s southeastern corner in 2014. Since then, they’ve done tens of millions of dollars in damage to the state’s agriculture and forestry; scientists have predicted losses in the hundreds of millions annually if the insects keep spreading. The ailanthus tree (also called the Tree of Heaven), another non-native from Asia, looks like home to them. By sucking nutrients from the tree, and by excreting a sugary excess called honeydew, which attracts a dark mold, the insects sometimes fatally weaken the trees. The ailanthus, the black walnut, and the staghorn sumac are three of their favorite victims. They also destroy an expensive agricultural plant: grapevines.

“I saw a spotted lanternfly on the windshield of my car when I came out of the Barnes & Noble in Clifton Commons,” one of the Rutgers Master Gardeners said. “I ran my wipers and brushed it off. When I got home, it was on the roof of the car!”

“Maybe that was a different spotted lanternfly,” a woman in an Indian-print blouse, who had stopped by with some S.L.F. questions, offered.

“Squash them whenever you see them!” Florence Rollino, who has been a Master Gardener for twenty-five years, said. “They jump really fast, and they jump far. You have to come at them from the front. That’s the direction they jump, like a plane taking off.”

“They’ve only got one real jump in them, so you can usually get them on the second jump,” Susan Ripoll, another Master Gardener, said. “Or so I’m told. I hate to kill anything. These insects are kind of lost. They’re still looking for a good environment.”

“I had the nymphs all over my deck in April,” the lady in the print blouse said. “I thought they were little spiders until I saw they had only six legs.” She added that deer regularly come up a set of steps to get onto her deck to eat her potted plants.

Spotted lanternflies mate in August, and the heightened activity of what the New York Post called the “sex-crazed bugs” likely explains why so many people recently became aware of them. The insects lay eggs from September through December. The eggs hatch into tiny black nymphs with white spots, in the first of four instars, or nymphal stages, each a larger bug than the preceding one. After the fourth instar, the nymphs molt into adults about an inch long. They mate and then lay eggs, often in places where you can’t see them, such as high up in trees. There may have been an abundance of their eggs in trees this year, and they are easy to miss, which is why we had no warning about this S.L.F. upsurge.

My sister Suzan Kwateng, a gardener with the New York City Parks Department, told me, “Spotted lanternflies are the most common insects that I see in the parks where I work in Staten Island. They’re all over Brooklyn Heights, by the new library.” Part of Sue’s job is spraying weed killer. “The honeydew that the bugs excrete makes leaves look kind of glassy when it gets on them,” she said. “Then it’s hard for me to tell if a patch of poison ivy has been sprayed already, because the spray on the leaves also gives them a glassy look.” She added that the bugs had also been seen “on the West Side of Manhattan, in Hudson Yards,” and that “they do seem to be taking over.” Downtown, they have lately been spotted on the sides of high-rise buildings. According to Penn State’s College of Agricultural Sciences, they are drawn to any tall vertical surfaces, and may appreciate the warmth that the glass and concrete in buildings provide. They’re not great fliers, but they can jump off and glide.

Cape May County, at the southernmost tip of New Jersey, got spotted lanternflies late, after every other county in the state. The county grows a lot of grapes, which is one reason that the state agricultural-experiment station in the city of Cape May Court House took an interest. I called Dr. Claudia Gil Arroyo, the agricultural agent for the county, and asked what kind of spotted-lanternfly presence she was seeing. She said the bugs are hard on plants that are already stressed, a category that includes most of what is being grown locally, because the county suffered a drought this year. So far, luckily, the bugs haven’t done any major damage to the grapevines, or to the apple or peach trees or blueberry bushes, which they also have a taste for. Certain insecticides do work on them, when applied directly.

Gil Arroyo said she has seen swarms of spotted lanternflies around lighted doors at night. They don’t bite or sting, but the swarms are gross even when they’re not on plants and trees, raining down honeydew. I remembered watching swallows and bats and bigger insects like dragonflies swooping through swarms of mayflies or moths and gorging themselves, and there have been reports of birds, spiders, and praying mantises attacking the spotted lanternfly, but no predators seem to be keying on them. Gil Arroyo said, “People are doing studies about that. It may be that the red on the hind wings looks like the kind of visual defense signal some animals use to warn a predator about their dangerousness or toxicity. The flash of red when they jump may be scaring off potential predators. So far, that’s just conjecture.” (According to Penn State Extension, to date there aren’t any known toxins in the insects.)

I sometimes see smashed spotted lanternflies on the outdoor track in a nearby park where I run. They make a gaudy mess, with the shambles of wings and the black spots and the bright-red fragments, like McDonald’s Happy Meal toys tossed out a car window and wheel-crushed repeatedly. The corpses are always at a corner of the track where squirrels drop green-and-black husks from the overhanging branches of a black walnut. Now I understand that the bugs are up there, too, doing their patient, slow number on the tree. ♦

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