Spotted lanternflies are back—here's how to keep them out of your yard

Many invasive pests hitchhike to the U.S. on plants, luggage, or in container ships and planes. The biggest issue is that because they have no natural competitors, these invasives can displace native species and multiply unchecked. One relatively recent and worrisome arrival is the spotted lanternfly, also known as SLF. First identified in Pennsylvania in 2014, spotted lanternfly has quickly expanded to neighboring states.

These pests aren’t actually flies. “SLF is a type of plant hopper that will swarm a plant and drain it of its sap using piercing, sucking mouthparts,” says Kelly Oten, PhD, assistant professor and extension specialist at North Carolina State University. “Their favorite plant is the invasive tree of heaven. But they feed on more than 100 species of plants, including agricultural crops such as hops, grapes, fruit trees, and hardwood trees.”

SLFs are great at catching a ride, which makes it easy for them to continue spreading. “While the adults are not great fliers, they’re active jumpers and crawlers and will crawl up something tall, then jump and flutter down, such as onto a vehicle, so that they’re transported elsewhere,” says David Coyle, PhD, associate professor of forest health and invasive species, and extension specialist at Clemson University. “The females also lay egg masses which are very difficult to detect on surfaces such as trees, rocks, grills, firewood, cars, campers, and trailers.”

Ahead, here’s how to ID and manage these nuisance pests.

Are spotted lanternflies dangerous?

Fortunately, SLFs don’t bite people or pets, but they’re extremely annoying when they hop around in large numbers on your deck or patio. In infested areas, they may climb around on you, or you may see them piled up dead on sidewalks or swarming the doors of buildings, says Oten.

SLFs also excrete a sweet, sticky substance called honeydew, the excess sugar and water from their feeding on plants. Honeydew can attract stinging insects, such as wasps, which isn’t what you want in outdoor spaces. Honeydew also contributes to the growth of sooty mold, unsightly black fungi that build up on plants or on surfaces such as picnic tables or kids’ play sets if located under an area where SLFs are feeding, says Coyle.

How to identify spotted lanternfly

SLF produce one generation per year, but the challenge is that each life stage looks totally different. The egg masses, which are laid in the fall, overwinter and resemble a yellowish-brownish smear of mud about an inch long. “They sort of look like dried-up Silly Putty,” says Coyle.

Nymphs hatch in the spring (March to May) and begin feeding on plants. At first, they’re ¼-inch long and black with white spots and leggy, resembling ticks. By late summer, the nymphs are about ¾-inch long with white spots and red patches, says Oten.

You’ll start seeing adults in August. These are the easiest stage to identify and won’t be mistaken for anything else because they’re so distinctive in appearance. They have brown forewings with black spots at the front and a speckled band at the rear. Hind wings are red with black spots at the front and white and black bars at the back. The abdomen is yellow with black bars, says Oten.

How to get rid of spotted lanternflies

Because these pests are spreading, you may eventually find them in your own garden. “If you find a spotted lanternfly in your yard, don't panic,” says Oten. “You probably won't be able to eliminate them entirely, but there are lots of options to manage them to reduce their presence in your yard, impact on your plants and your enjoyment of your backyard.” Here’s what to do.

Target your attack

“Focus efforts where their populations are causing the most issues for you, such as on a high-value shade tree,” says Oten. Your local university coop extension service agent (find yours here) can offer guidance on how to manage them, or you may need to call a certified arborist to assist with large trees. Fortunately, most healthy plants can take some feeding. You also should remove their favorite host plant, tree of heaven, if there’s one on your property.

Report sitings

This pest already is known to have infested parts of the Northeast and Mid-Atlantic. But if you’re in doubt or in an area where SLF is not yet known to occur, report it to your state's agriculture department (find yours here), says Coyle.

Look for egg masses

In the fall and winter, inspect surfaces around your home for egg masses. Scrape them off, then crush them. This can reduce the numbers of SLFs next year, says Oten.

Smash the adults

It can get messy, but it’s fine to go old-school and simply stomp or squash the bugs. Then hose off the area, says Coyle.

Skip DIY concoctions for adults

There’s no solid scientific evidence that any DIY home remedy works to repel or kill SLFs. That includes essential oils, bleach, hot water, hair spray, or any other mixture, says Coyle.

Make a DIY trap for egg masses

Sticky bands are no longer recommended because they can trap non-target creatures such as birds. Circle traps were once suggested, but they’re difficult to set and often ineffective. Instead, make a lampshade trap. “The traps are highly attractive to females for egg laying,” says Oten. “You can set them in July or August, leave them up through the egg-laying season, and remove and destroy them in November. Each egg mass can have 30 to 50 eggs in it. Removing them will greatly reduce the number of babies hatching the next spring.” Learn how to make a lampshade trap here.

Inspect items before moving

Look for egg masses on tarps, trailers, containers, propane tanks, and other items stored outdoors so you don’t accidentally bring them with you to your new home. Also, if you’re traveling through a quarantine area where SLFs are found, check your vehicle, including doors, bumpers, grills and wheel wells, for egg masses and adult hitchhikers.