Every county in New Jersey is now under a spotted lanternfly quarantine. The invasive pest, first detected in the U.S. in 2014, has spread across the entire state, feeding on more than 70 plant species and threatening agriculture, hardwood trees, and backyard gardens alike. Here’s what you need to know to identify them, understand the damage, and fight back on your own property.
How to Identify Spotted Lanternflies
Spotted lanternflies look different depending on their life stage, and knowing what to look for at each phase helps you catch them earlier in the season.
The earliest nymphs, active from May through July, are small (a few millimeters up to about a quarter inch), black with white spots, and wingless. They’re strong jumpers and will hop away quickly if disturbed. Starting in July, the later-stage nymphs shift to a striking bright red with black stripes and white spots, roughly half an inch long. These are the ones most people notice first because the color is hard to miss.
Adults appear from July all the way through December. At rest, they display gray forewings covered in black spots of varying sizes, with the wingtips showing black spots outlined in gray. The real giveaway is underneath: the hind wings have bold patches of red and black separated by a white band. The body has black legs and head with a yellow abdomen banded in black. Adults prefer to hop and glide rather than fly, so you’ll often see those colorful hind wings flash open when they jump or feel threatened.
Egg Masses: What to Look For
Egg masses are the overwintering stage, visible from September through June. Adults don’t survive the winter, but their eggs do. Each female can lay up to two egg masses, and each mass contains 30 to 50 eggs packed into a patch about one inch across.
Fresh egg masses look like a smear of gray mud. As they age over the winter, the covering dries to a light tan and starts to crack, resembling dried mud. Hatched egg masses lose the coating entirely, revealing rows of tiny seed-like individual eggs. You’ll find them on tree trunks, fence posts, outdoor furniture, vehicles, stone walls, and almost any flat outdoor surface. Checking for and destroying egg masses between fall and early spring is one of the most effective things a homeowner can do.
Why They’re a Problem in New Jersey
Spotted lanternflies feed by piercing plant tissue and sucking out sap. They have a strong preference for economically important plants, including grapevines, maples, and black walnut trees. Heavy feeding significantly stresses plants, weakening them over time and potentially killing them. For New Jersey’s grape growers and the broader agricultural industry, the threat is serious.
The damage goes beyond the plants themselves. As they feed, spotted lanternflies excrete a sugary waste called honeydew. This sticky residue coats leaves, branches, patio furniture, cars, decks, and anything else beneath a feeding site. Honeydew attracts bees, wasps, and other insects, and it promotes the growth of sooty mold, a dark fungus that can blanket plants and outdoor surfaces. Homeowners near heavily infested trees often describe their yards as sticky and covered in black mold.
Their Favorite Host Plant
The spotted lanternfly’s preferred host is the Tree of Heaven, an invasive tree from Asia that’s common across New Jersey. If you have one on your property, it’s essentially a magnet for the pest. The New Jersey Department of Agriculture recommends removing Tree of Heaven when practical, using an herbicide to ensure the roots don’t resprout. Simply cutting it down without treating it often causes aggressive suckering, which can make the problem worse.
Beyond Tree of Heaven, home gardeners have reported spotted lanternflies feeding on cucumbers, basil, roses, peonies, Russian sage, and many other backyard plants. Removing wild grape and oriental bittersweet from your property can also help reduce local populations, since these are preferred food sources.
What Homeowners Can Do
Scrape Egg Masses
From September through the following spring, check trees, fences, and outdoor surfaces for egg masses. Scrape them off with a flat tool (a putty knife or old credit card works well) into a container of rubbing alcohol or hand sanitizer, and leave them in the solution permanently. You can also smash them thoroughly. This is free, takes minutes, and can eliminate 30 to 50 lanternflies per mass before they ever hatch.
Use Circle Traps
Funnel-style “circle traps” are the recommended trapping method. They wrap around a tree trunk and funnel climbing nymphs and adults into a collection container. You can build one yourself with online guides from Penn State Extension. Sticky bands are another option but come with a significant downside: they catch birds, squirrels, butterflies, and pollinators indiscriminately. If you do use sticky bands, always install a wildlife barrier around them and check the bands daily.
Low-Toxicity Sprays
Several reduced-toxicity insecticides work well against spotted lanternflies, and some carry organic labels:
- Neem oil: Good effectiveness on contact, poor residual activity
- Natural pyrethrins: Excellent on contact, poor residual activity
- Insecticidal soaps: Good on contact, poor residual activity
- Horticultural spray oil: Good on contact, poor residual activity
The tradeoff with all of these is that they work well when sprayed directly on the insects but don’t linger on surfaces to kill lanternflies that arrive later. For heavily infested trees, systemic treatments applied to the soil or trunk can provide longer-lasting protection during the peak feeding months of July through September. These are stronger chemicals, so reading the label carefully and following application instructions matters.
The Statewide Quarantine
All 21 New Jersey counties are under a spotted lanternfly quarantine. For homeowners, this is mostly informational, but it has real implications for businesses. Any company or organization that moves goods, vehicles, or equipment within or out of the quarantine zone during the course of their work must obtain a permit from the New Jersey Department of Agriculture. The quarantine exists because spotted lanternflies spread primarily as hitchhikers, riding on vehicles, lumber, stone, and outdoor equipment to new areas.
Before driving out of state or moving outdoor items, it’s worth doing a quick check of your vehicle and belongings for egg masses or adult lanternflies. A single overlooked egg mass on a trailer or pallet can establish a new population hundreds of miles away.
Seasonal Calendar for New Jersey
Knowing when each life stage appears helps you time your control efforts:
- September through June: Egg masses present on surfaces. Best window for scraping is fall through early spring before hatching begins.
- Late April through June: Eggs hatch. Early nymphs (black with white spots) begin emerging.
- May through July: Early-stage nymphs are active and feeding.
- July through September: Red nymphs appear. Adults begin emerging in July.
- July through December: Adults are active, feeding, mating, and eventually laying eggs.
- September through December: Egg-laying season. Females deposit masses on nearly any outdoor surface.
The heaviest feeding pressure, and the most visible infestations, occur from July through October. That’s when honeydew, sooty mold, and swarms of adults on trees are most noticeable. By December, the adults die off, but the next generation is already secured in egg masses waiting out the winter.