Yes, you should kill spotted lanternflies whenever you see them. Multiple state agriculture departments across the eastern United States actively encourage residents to stomp, squash, or otherwise destroy this invasive pest on sight. The spotted lanternfly feeds on more than 65 plant species, poses a threat worth hundreds of millions of dollars to U.S. agriculture, and has no natural predators in North America to keep its population in check.
Why “Kill on Sight” Exists
The spotted lanternfly is native to Asia and was first detected in Pennsylvania in 2014. It’s a sap-feeding insect that targets grapevines, maple trees, black walnut, fruit trees, hardwoods, and dozens of other plants. When populations build up on a host plant, the feeding drains stored starches and sugars so aggressively that it can weaken the plant’s ability to survive winter, reduce or eliminate the next season’s crop, and eventually kill the plant outright.
Grapes are especially vulnerable. Heavy infestations on vineyard vines have been shown to cause vine death. But the damage goes beyond direct feeding. Spotted lanternflies consume so much sap that they excrete large amounts of a sticky sugar-water waste called honeydew. This honeydew coats leaves, fruit, outdoor furniture, vehicles, pets, and anything else beneath an infested tree. It then becomes a growth medium for sooty mold, a dark fungus that can make fruit unmarketable and block sunlight from reaching leaves. The honeydew also ferments, producing an odor that attracts bees and wasps, increasing the risk of stings around infested areas.
Pennsylvania alone could lose hundreds of millions of dollars and thousands of jobs if the pest spreads unchecked. The grape, orchard, nursery, and logging industries are all at risk. Because no single control method can contain an insect this prolific, agencies rely partly on the public to kill individual insects and destroy egg masses wherever they’re found.
How to Identify Them by Season
Spotted lanternflies look different depending on the time of year, and knowing what to look for means you can destroy them at every life stage.
Egg masses (September through June): Freshly laid egg masses are about one inch long and covered in a white, putty-like substance. They’re deposited on nearly any hard outdoor surface: tree trunks, stones, patio furniture, vehicle bumpers, shipping containers. As the coating ages, it cracks and looks like dried mud. Eventually it wears off completely, revealing rows of small, seed-like eggs underneath. These are easy to miss if you’re not looking carefully.
Early nymphs (May through July): First through third instar nymphs are tiny, starting at just a few millimeters and growing to about a quarter inch. They’re black with bright white spots and are strong jumpers. You’ll often find them on young shoots of plants and trees.
Late nymphs (July through mid-August): Fourth instar nymphs are about half an inch long and shift to bright red with black stripes and white spots. They’re also strong jumpers and tend to feed on older, woodier plant tissue.
Adults (July through December): Adults are roughly one inch long with gray forewings dotted in black spots. When they fly or feel threatened, they flash their hind wings, which are bright red, black, and white. Adults prefer to jump and glide rather than fly long distances. Egg laying occurs from September through November or until the first hard freeze.
How to Kill Spotted Lanternflies
Stomping and Squashing
The simplest method. Nymphs and adults are relatively slow compared to other insects, especially when resting on tree trunks or flat surfaces. Nymphs will jump when startled, so approach carefully. Adults can fly short distances but often don’t react quickly enough to escape a shoe.
Destroying Egg Masses
This is one of the highest-impact things you can do, since a single egg mass can contain 30 to 50 eggs. Use a plastic card, putty knife, or any hard flat edge to scrape the mass off the surface. Scrape it directly into a resealable bag containing rubbing alcohol or hand sanitizer, then seal the bag. Leave the eggs submerged permanently. Simply scraping eggs onto the ground won’t reliably kill them. You can also smash egg masses thoroughly against the surface where they’re laid, but the alcohol method is more certain.
Sprays That Work
Both nymphs and adults are fairly easy to kill with insecticides. For homeowners who prefer lower-toxicity options, insecticidal soap, neem oil, and horticultural spray oil all provide good results when sprayed directly on the insect. These require thorough coverage to work and don’t remain active after drying. Natural pyrethrins offer excellent kill rates with similarly short residual activity. For longer-lasting protection on heavily infested trees, products containing bifenthrin provide excellent activity and stay effective for days after application.
The Tree of Heaven Connection
Spotted lanternflies feed on many species, but their overwhelming favorite is the tree of heaven, another invasive species from Asia that grows aggressively across the eastern U.S. The abundance of this tree provides a ready food source that helps spotted lanternfly populations multiply and expand their range.
If you have tree of heaven on your property, removing most of them while leaving one or two standing creates what’s called a trap tree. The remaining trees concentrate the insects in one location, where they can be treated with insecticide more effectively. Simply cutting tree of heaven to the ground doesn’t work on its own, because the tree sends up vigorous sprouts from the stump and roots. Chemical treatment of the stump or trunk is needed to fully kill it.
Reporting and Preventing Spread
If you spot a lanternfly outside a known infestation area, report it to your state’s department of agriculture immediately. The USDA’s Animal and Plant Health Inspection Service maintains state-by-state contact information for reporting. Early detection of new populations is one of the most effective tools for containment.
Several states have established quarantine zones where spotted lanternfly is established. If you live in or travel through one of these areas, check your vehicle, outdoor gear, and clothing before heading to a new location. Egg masses cling to almost any surface and are easily transported on cars, trailers, firewood, and shipping pallets. Businesses that move goods through quarantine zones should inspect containers, propane tanks, and anything stored outdoors before shipping. Quarantine boundaries are regularly expanded as new infestations appear, so check your state’s current map if you’re near a known population.
What Happens if You Do Nothing
A single property with a few spotted lanternflies might not seem like a crisis, but the insects reproduce quickly and spread efficiently. In residential areas, heavy infestations turn backyards into sticky, mold-covered, wasp-attracting messes. Honeydew coats decks, outdoor furniture, and anything left outside. For anyone growing backyard grapes, fruit trees, or ornamental maples, even a moderate population can cause visible wilting, reduced fruit quality, and branch dieback. Killing every one you see, destroying every egg mass you find, and reporting new sightings all contribute to slowing a pest that has no biological controls keeping it in check.