10 Key Insights About the Spotted Lanternfly

You’re likely familiar with Lycorma delicatula, commonly referred to as the spotted lanternfly (abbreviated as “SLF”). This vibrant planthopper, closely related to cicadas, originates from China and various regions in Asia. Over the last ten years, it has migrated across the globe, establishing itself as one of the most infamous invasive species in the U.S. Its feeding habits pose a significant threat to agriculture and vineyards, endangering industries valued at hundreds of millions of dollars. Here’s what you need to know about these striking yet troublesome insects. 

1. Imported stone shipments may have introduced the spotted lanternfly to the U.S.  

The first U.S. sighting of the SLF occurred in Berks County, Pennsylvania, in 2014. Experts believe the insects likely emerged from eggs transported in a consignment of Chinese stones two years prior. Regrettably, their presence has since expanded far beyond that initial location.

2. Over a dozen states are now dealing with infestations.

The New York State Integrated Pest Management Program (NYSIPM) provides an interactive map tracking the spotted lanternfly’s expansion. As of June 2023, SLFs have been found in regions of Pennsylvania, New York, New Jersey, Connecticut, Rhode Island, Massachusetts, Maryland, Delaware, Virginia, North Carolina, Ohio, Indiana, Michigan, and Iowa. Reports have also surfaced in Vermont and New Hampshire.  

3. Mature spotted lanternflies feature pinkish-tan wings adorned with black spots.  

Lycorma delicatula undergoes multiple life stages. Adult females lay one or two egg masses, each containing up to 60 eggs, between September and November. They coat these eggs with a sticky substance that hardens into a gray or tan camouflage. By late May or June, small instar nymphs—black with white spots and about a quarter-inch long—emerge.

The first instar nymphs grow to triple their initial size, transitioning to a bright red color (the fourth instar) between July and September. Eventually, they mature into inch-long adults with pinkish-tan wings dotted in black, and their hindwings display striking red, black, and white patterns.

4. Grapevines are particularly at risk from spotted lanternflies.   

As stated by the New York State Department of Environmental Conservation, both nymph and adult spotted lanternflies consume over 70 plant species using their “piercing mouthparts … This feeding, often by thousands of SLF, weakens plants, leaving them susceptible to disease and other insect infestations.”

Grapevines are especially threatened by spotted lanternflies. In Pennsylvania, some commercial growers have reported losing up to 90 percent of their grape harvests due to these pests, which can damage or destroy vines. Wineries in the northeastern U.S. are increasingly worried, and experts warn of potential devastation if the lanternflies reach California, home to its renowned $170.5 billion wine industry. Other crops, including apples and walnuts, are also at risk.

5. Lanternfly waste poses an additional challenge.  

The sugary liquid excrement, known as “honeydew,” is excreted by spotted lanternflies and other insects after feeding. It’s extremely sticky and sugar-rich, prompting bees to produce honey from it during seasons when nectar is scarce. (Erik Diemer, co-owner of Pocono Apiaries—which bottles and sells this honey—told Lehigh Valley Live, “I can’t sell lanternfly honey as regular honey because customers might think it tastes burnt.”) While this is nature’s way of turning waste into something useful, honeydew has drawbacks: it encourages mold growth that harms crops and attracts stinging insects, including bees. 

6. Spotted lanternflies do not sting or bite humans.

There’s no evidence indicating that SLFs are harmful to humans or pets. However, pet owners should remain cautious; the bugs’ hard exoskeletons could lead to digestive issues if ingested by dogs or cats. 

7. They can spread to new areas by clinging to cars and personal items.    

Spotted lanternfly egg masses are typically found on rocks or tree branches, but as Penn State entomologist Julie Urban explained in a 2022 WNYC Radio interview, “They lay eggs on almost anything, not just surfaces their offspring can feed on but also on man-made objects.” This includes items like kiddie pools, rusty metal, firewood stacks—and even vehicles. Unknowing drivers can inadvertently transport SLFs to new areas. “If you’ve been in a spotted lanternfly-infested zone, thoroughly inspect your vehicle for egg masses, adults, and nymphs,” advises a brochure from Cornell University and the NYSIPM. Travelers should also examine their belongings, such as camping equipment, outdoor tools, and construction materials.

8. Multiple methods exist to eliminate spotted lanternflies.

In their native habitat, SLFs are kept in check by natural predators, preventing significant issues. However, in North America, humans must step in to manage the infestation. Egg masses can be eliminated by crushing them with a plastic card or similar tool and scraping them into a bag filled with alcohol or hand sanitizer.

Insecticides can be used to target adult spotted lanternflies, though consulting a certified applicator is advisable. Alternatively, the traditional method of stomping on the bugs works too. Some communities have turned this into a fun activity: On August 28, 2021, approximately 80 people in Bordentown, New Jersey, participated in a “Lanternfly Murder Pub Crawl.” Attendees visited local bars while crushing around 6000 SLFs along the way, with prizes awarded for the highest number of kills.

For those uncomfortable with stomping, spotted lanternflies can be trapped using a water bottle. As Smithsonian explains, “when threatened, the bugs instinctively jump away. … You can exploit this behavior by holding an open water bottle above them. The lanternflies will leap inside, allowing for easy capture. (Be sure to cap the bottle between catches to prevent escapes.) Once the bottle is full, placing it in the freezer humanely kills the insects.” 

9. Spotted lanternflies struggle to survive indoors. 

Homeowners need not fret over spotted lanternflies entering their homes: Studies indicate they cannot survive more than 48 hours at room temperature. Similar to stinkbugs, crushing them indoors is ill-advised, as the honeydew from smashed lanternflies can stain fabrics or draw stinging insects. As reported by S.I. Live, “it’s better to leave them be … and sweep them up after a day or two.”

10. Some native insects resemble spotted lanternflies.

While it’s tempting to stomp on any insect resembling an SLF, consult a reliable field guide first: Native species like the figured tiger moth or the large milkweed bug [PDF] can easily be mistaken for invasive lanternflies.