The Spotted Lanternfly Is Spreading—Here’s How to Combat the Invasive Pest

The Spotted Lanternfly is decimating trees, orchards, vineyards, and other plants on the East Coast (and beyond). Here’s how to protect your landscape from damage.

By Debbie Wolfe and Teresa Odle | Updated Jul 21, 2022 10:38 AM

Top view of spotted lanternfly, Chester County, Pennsylvania

Photo: istockphoto.com

First detected in the United States in 2014, the Spotted Lanternfly (Lycorma delicatula) has made its way across the East Coast, killing plants and trees, and leaving a sticky residue on porches and patios. It didn’t take long for this Asian bug to be deemed a significant threat to crops by the U.S. Department of Agriculture.

From its initial spread within Pennsylvania to 11 Eastern states, the Spotted Lanternfly is a risk to plants in nearly every state. Isolated reports have cropped up in Ohio, Utah, Kansas, California, and Oregon. Although that seems like a long way to fly (or more accurately, hop), the insect lays eggs on vehicles, firewood, and other objects that travel more freely, helping to speed the spread.

In Pennsylvania alone, the Spotted Lanternfly could lead to a loss of at least 2,800 jobs and $324 million a year from the state’s economy because of its damage to forests and crops. A 2019 grant awarded to Penn State is supporting a collaborative effort to develop strategies to combat the pest. In North Carolina and Oregon, dogs have been trained by the USDA to detect the invasive pests.

What can homeowners without detector dogs do for now to protect themselves from this latest threat to the landscape? The USDA, state extension offices, and Kathy Glassey, director of renewable resources for Monster Tree Service, offer expert tips and advice on how to care for plants in the face of the Spotted Lanternfly.

What is the Spotted Lanternfly?

The Spotted Lanternfly (SLF) is a planthopper that originated in northern China. The adults have four wings. The front wings are grayish and have dark spots, and the back wings are black-tipped, white in the center, and bright red near the body. SLF females are 24 to 27 millimeters long, while males measure 21 to 22 millimeters.

Though it sounds from their description like the SLF would be fairly easy to spot, the insect undergoes five stages of instars, or growth periods, in which they look entirely different. They lay eggs from August to early November, which overwinter and hatch in late spring. The insects are relatively small throughout their instars and are often confused with ticks during their first through third instars.

“You can see these stages from about May through July,” says Glassey, “The fourth instar nymph has the first distinctive red color.” By late summer, the insect has reached its adulthood and congregates on trees. “The adults do not fly in the traditional sense,” explains Glassey, “But rather hop and glide.”

spotted lanternfly

Photo: istockphoto.com

How did the Spotted Lanternfly get here?

The SLF’s native range includes China, India, and Vietnam. It was first reported outside these countries in South Korea in 1932 and has since become abundant in Korea and Japan. The insect arrived in Berks County, Pennsylvania, via an overseas shipment in 2014 and has since spread through other states.

“Global commerce has created transportation opportunities for invasive pests to hitchhike and become introduced to new regions not exposed previously,” says Glassey. “The Spotted Lanternfly is a great hitchhiker and can travel along railroads or on cars, maybe even up to 60 miles per hour!”

Where has the Spotted Lanternfly spread?

In addition to Pennsylvania, the SLF is considered a threat in Connecticut, Delaware, Indiana, Maryland, Massachusetts, New Jersey, New York, Ohio, Virginia, and West Virginia. Although some states’ conditions are less suitable for the insect to take hold, most have at least one area with some risk based on local climate. The risk is highest across the northeast states where it’s already a threat, along with parts of California, Oregon, and Washington. In 2021, the state of California established quarantine measures to prevent the insect from entering the state from infested areas.

Just like how they hitchhike on global transports, these prolific pests can travel throughout the United States on nearly any wood product, vehicle, or commodity. The insect is considered an invasive species in the United States and South Korea.

spotted lanternfly

Photo: istockphoto.com

What type of damage does the pest do?

The Spotted Lanternfly can be found on nearly 100 species of plants, especially trees with smooth bark. They feed on sap in the phloem, the living tissue in vascular plants, which causes the trees stress and eventual decline. As they feed, SLFs excrete honeydew, a sugar-rich sticky liquid. Honeydew buildup promotes fungal, sooty mold to grow on the plant’s surface. The mold grows in black mats, interrupting the host plant’s ability to photosynthesize by blocking sunlight from the leaves’ surfaces. The honeydew also attracts other insects that can damage the plant.

The honeydew also doubles as the SLF’s breeding ground. “Adult females lay egg masses that, on average, can contain 30 to 50 eggs,” explains Glassey, “These egg masses have been found in many places, including trees, tires, patio furniture, decks, fencing, and so much more.”

The pest is particularly detrimental to grapes, apples, oaks, maples, and walnuts. They cause extensive damage to the logging, wine, and orchard industries, to name a few. “It is critical to continue eradicating this pest,” warns Glassey, “as it presents a significant economic impact on our nation’s resources.”

spotted lanternfly

Photo: istockphoto.com

What can homeowners do to stop the Spotted Lanternfly?

Early detection is the best defense. The pest can be destroyed throughout its various instars. “If egg masses are found, they can be scraped with a card and destroyed,” says Glassey. Egg masses can be found on any vertical surface and look like a smear of mud. When doing fall cleanup and winter prep, check all outdoor items for egg masses, scrape them into a ziplock bag, and add hand sanitizer to cover them. Then zip it shut and dispose of the bag.

Regularly checking trees and plants for signs of Spotted Lanternfly eggs or damage is important for anyone living in an area where the pest already is deemed a threat or where the potential exists. Be sure to report your sighting to your local agriculture office as well.

RELATED: Is This $50 Product the Secret Weapon to Getting Rid of Spotted Lanternflies?

The insects tend to gather at dusk or nighttime, and might be easier to spot then. Catching nymph or adult SLFs is challenging because they are mobile. Spraying them with insecticide can be effective if you can catch them gathering. EPA-registered chemicals that work on contact or systemically include dinotefuran, bifenthrin, zeta-cypermethrin, and carbaryl. Less-toxic choices such as oils and soaps also can be effective. Sticky traps might hold them until you can dispose of them. As with any pest control, use prevention first, then the least toxic choice if prevention fails. Research effective biopesticides that can destroy Spotted Lanternflies without harming beneficial insects continues.

Glassey says using common sense and due diligence can help stop the SLF from spreading. “If traveling through or if you live in a confirmed SLF area, be sure you have no hitchhikers traveling with you,” she says. “Follow your state’s quarantine guidelines and consider hiring a professional arborist to evaluate and provide treatment options.”

Further, if you have an Ailanthus altissima (or tree of heaven, an invasive tree and noxious weed) on your property, you may want to replace it. “SLF prefers this invasive tree species,” explains Glassey. Removing these trees from your property may keep the SLF from entering your landscape in the first place. To be on the safe side, have a professional inspect your tree and shrubs yearly to ensure early detection.