pest-control

Spotted Lanternfly in Maryland: What Homeowners Should Do Before the Egg-Laying Season

Spotted lanternfly in Maryland: how to identify adults and egg masses, protect trees and decks, remove tree of heaven, and what the state quarantine requires.

Spotted Lanternfly in Maryland: What Homeowners Should Do Before the Egg-Laying Season

The insects clustered on your maple trunk in late August are adult spotted lanternflies, roughly an inch long, with gray forewings dotted in black and bright red hindwings that flash when they jump. They arrived in Maryland in Cecil County in 2018 and have spread across most of the state since.

August into September is the stretch that decides how many you see next summer. Adults are feeding, mating, and about to start laying egg masses on anything with a flat surface, and each mass holds somewhere around 30 to 50 eggs.

Eradication is off the table at this point. What a homeowner can realistically do is cut the population on their own property, protect the plants that are genuinely at risk, and avoid the treatments that cause more harm than the insect does.

What You Are Looking At Right Now

Adults are the stage most people notice, partly because they are large and partly because they gather in numbers on trunks at dusk. Earlier in the season the same insect looked entirely different, moving through black nymphs with white spots in late spring, then bright red nymphs with white spots by midsummer.

They are poor fliers and strong jumpers. A lanternfly startled off a trunk launches sideways rather than taking flight, which is why swatting one usually sends it to another part of the same tree. They do not bite, they do not sting, and they carry no disease.

Feeding happens through a straw-like mouthpart that taps the phloem under the bark. Nothing chews leaves, so ragged foliage on your dogwood is a different problem. What lanternflies leave behind is sap loss and a steady drip of sugary waste.

Numbers swing hard year to year in any given yard. A property that was covered in 2025 can be quiet the following August and heavy again the year after, which makes single season judgments about what worked unreliable.

What They Harm and What They Leave Alone

Grapevines take the worst of it. Maryland's vineyards in Frederick, Carroll, and Washington counties treat this insect as a production threat, because sustained feeding on vines cuts winter hardiness and can kill a planting outright. Backyard grape arbors face the same risk.

Young saplings and nursery stock are the second real casualty. A tree with a trunk under about three inches has limited reserves, and a heavy feeding load two summers running can finish it.

Mature shade trees are a different story. Established maples, willows, river birch, and black walnut host large populations and look terrible doing it, yet outright death from lanternfly feeding alone is uncommon. The realistic outcome is a stressed tree that handles drought, Chesapeake humidity, and root damage worse than it otherwise would.

Your house is not on the menu. They do not bore into siding, they do not nest in walls, and they do not damage structural wood. Adults will crawl on a Baltimore row home's brick face and lay eggs there, which is a nuisance and a transport risk rather than a building problem.

Honeydew and the Mess Under the Tree

Honeydew is the part that pushes people to call a pest control company. A maple carrying a few thousand insects drips sugar water all day, and anything under the canopy gets coated: decks, patio furniture, grills, cars, pool covers, and the shrubs planted below.

Black sooty mold grows on that residue within days. It shows up as a dark film on deck boards, hostas, and boxwood, and while it does not infect the plant directly, a thick layer blocks enough light to weaken it over a season.

Yellowjackets, hornets, and ants follow the sugar. Late summer wasp activity around a deck in a lanternfly year is often a honeydew problem wearing a different costume, and treating the wasps without addressing the source buys a week.

Cleanup is manageable if you get to it early. Washing a deck before mold sets in is a hose and a stiff brush, while a season of buildup usually means a professional pressure wash at roughly $200 to $600 and sometimes a resealing job on top of that.

Protecting Cars, Decks, and Pools

Move what you can out from under the drip line. A car parked under an infested silver maple in Towson for a week comes back with a film that takes more than a standard wash to remove, and the residue can dull clear coat if it bakes on.

Covering a pool at night helps less than people hope, since the insects fall in during the day. Skimming daily through late August and September is the practical answer, along with checking the filter basket more often than usual.

Tree of Heaven Sits at the Center of the Problem

Ailanthus altissima, better known as tree of heaven, is the lanternfly's preferred host and the single biggest driver of a heavy yard population. It grows fast in alleys, fence lines, highway edges, and behind garages, and Maryland has an enormous amount of it.

Identifying it takes thirty seconds. Look for long compound leaves with 11 to 41 leaflets, a small bump with a gland on the underside near each leaflet base, and a strong smell like rancid peanut butter when you crush a leaf. Sumac looks similar and has toothed leaflets, so check the edges.

Cutting one down without treating the stump makes the situation worse. The root system responds by sending up dozens of suckers across a wide area, and within two years you have a thicket where you had one tree. Removal with a cut-stump herbicide application at the time of cutting is the method that holds, and it typically runs $400 to $1,500 depending on size and access.

Some property managers keep one male tree of heaven, treat it with a systemic insecticide, and let it work as a trap. That approach takes commitment and correct timing, and it is worth discussing with an arborist rather than improvising.

Steps Worth Taking on Your Own Property

Scraping egg masses is the highest value hour a homeowner spends on this insect. From mid September into spring, look for masses that resemble a smear of gray putty about an inch long, sometimes covered and sometimes exposed and looking like rows of tiny seeds.

Check the surfaces people forget. Egg masses show up far from trees, and a fall walk around the property with a plastic card and a bag of rubbing alcohol or hand sanitizer covers most of it:

• Trunks and undersides of large limbs, especially on the smooth bark of maple and birch
• Grills, patio furniture, umbrella bases, and stacked firewood
• Trailers, boats, campers, and the wheel wells of vehicles parked outside
• Stone walls, retaining blocks, fence posts, and the backs of shed doors
• Nursery pots, landscape stone pallets, and anything delivered from an infested area

Scrape into the bag rather than onto the ground. Masses knocked loose and left on soil can still hatch, so the point of the alcohol is to finish them.

Killing adults by hand is satisfying and close to meaningless at the population level. Do it if you like, but do not confuse it with control, and do not let it substitute for removing tree of heaven and scraping eggs.

Treatments and Traps People Get Wrong

Sticky bands wrapped around a trunk catch lanternflies and also catch birds, squirrels, and bats. Maryland naturalists have documented enough of that to make plain sticky tape a poor choice. If you band a tree, cage the band in wire mesh, or use a circle trap that funnels insects into a collection bag instead.

Home remedies cause most of the plant damage attributed to this insect. Dish soap sprays, vinegar, gasoline, and homemade oil mixes burn foliage, kill beneficial insects, and in a few cases have killed the tree the homeowner was trying to save. There is no household mixture that solves this.

Contact insecticides labeled for the pest do knock down adults on contact, and the effect lasts days rather than weeks because new insects walk in from next door. Anything applied to a flowering plant risks pollinators, so keep applications off blooms and off anything bees are working.

When Hiring a Professional Makes Sense

Bring in a licensed applicator when you have high value trees, a vineyard or orchard planting, or a population dense enough that honeydew is damaging property. A basic property treatment for adults generally runs $150 to $400 per visit, and repeat visits through late summer are typical.

Systemic trunk injections or soil drenches on specific trees cost more, often $200 to $600 per tree depending on diameter, and they last a full season. Talk through pollinator exposure before agreeing to a soil applied systemic near flowering plants. Getting quotes from two or three licensed pest control companies serving your county on the same scope keeps the comparison honest.

Maryland's Quarantine and Reporting

The Maryland Department of Agriculture maintains a spotted lanternfly quarantine that has expanded steadily since the first Cecil County find, and it now covers a large share of the state. Businesses that move regulated articles such as landscaping material, nursery stock, firewood, and construction equipment out of the quarantine zone must hold a permit issued by the department.

Homeowners carry a lighter version of the same responsibility. Before hauling firewood, potted plants, or outdoor furniture to a property outside the zone, walk the load and check for egg masses and adults. Moving firewood is how this insect covered ground faster than it could ever fly.

Reporting still helps in parts of western Maryland and the lower Eastern Shore where populations are thinner. The department accepts online reports with photos, and a confirmed sighting in a new county shapes where survey crews work the following season. Our seasonal home maintenance guides for Maryland cover the fall yard checklist this scraping work belongs in.

Frequently Asked Questions

Will spotted lanternflies kill the maple tree in my yard?

An established maple usually survives, though a heavy population for consecutive summers leaves it stressed and slower to recover from drought. Trees under about three inches in trunk diameter face real risk and are worth protecting with a targeted treatment.

Are spotted lanternflies dangerous to people or pets?

No. They have no biting or stinging mouthparts and carry no known disease. A dog that eats a few will generally be fine, though any insect eaten off a recently treated plant is a reason to call your veterinarian.

What do the egg masses look like and when do they appear?

Laying starts around mid September in most of Maryland and continues until hard frost. A fresh mass looks like a one inch smear of gray putty, and once the coating wears away it looks like four to seven neat rows of brown seeds pressed against the bark.

Should I still be squishing them in August?

Hand killing adults has almost no effect on next year's numbers, since the insects on your tree today are a fraction of the local population. Time spent finding and removing tree of heaven does far more.

Do I have to report a sighting to the state?

Reporting is voluntary for homeowners and most useful in counties where the insect has not been confirmed. If you live inside the quarantine area, the department already knows, and your effort is better spent on egg scraping and host removal.