Spotted lanternflies have established themselves in the Pittsburgh area as part of their westward spread across Pennsylvania. Allegheny County is among the Pennsylvania counties under the state’s official spotted lanternfly quarantine, meaning these invasive pests are confirmed present and residents have a role to play in slowing their spread. If you’re seeing them on your property, in your backyard, or swarming trees along city streets, here’s what you need to know.
Why Pittsburgh Is in the Quarantine Zone
Pennsylvania’s Department of Agriculture maintains an expanding quarantine order for spotted lanternfly, and Allegheny County is on the 2025 list. Being inside the quarantine zone means these insects are breeding locally, not just passing through. It also means there are legal guidelines about moving outdoor items that could carry egg masses, like firewood, outdoor furniture, or landscaping materials, out of the quarantine area without inspection.
The quarantine exists because spotted lanternfly threatens nearly $18 billion worth of Pennsylvania’s agricultural economy, including grape, tree fruit, hardwood, and nursery industries. Pittsburgh residents may not run vineyards, but the insects feed on more than 70 species of plants and trees, making residential yards, parks, and urban tree canopy all fair game.
What They Look Like Through the Year
Spotted lanternflies produce one generation per year. Adults die off in winter, but before they do, females lay egg masses containing 30 to 50 eggs each. These egg masses overwinter on trees, rocks, outdoor furniture, vehicles, and nearly any flat surface. They look like smears of dried mud, roughly an inch long, and are easy to miss.
Eggs hatch in spring, releasing small black nymphs with white spots. As they grow through summer, older nymphs develop red patches. By late summer and into fall, they reach their adult stage: roughly an inch long, with gray wings dotted in black spots and vivid red hindwings visible in flight. This is when Pittsburgh residents notice them most, as adults swarm trees and gather in large numbers on trunks and outdoor surfaces.
Their Favorite Trees in Your Yard
The tree of heaven is their preferred host. This fast-growing invasive tree is common throughout Pittsburgh’s hillsides, vacant lots, and urban corridors. It has long compound leaves and a distinctive sour smell when cut. If you have tree of heaven on or near your property, expect spotted lanternflies to congregate there heavily.
But they don’t stop at tree of heaven. Spotted lanternflies feed on maples, black walnut, birch, willow, and many ornamental plants. They feed by piercing bark and stems to drink sap, then excrete a sticky substance called honeydew that coats surfaces below and promotes the growth of sooty mold. You’ll notice it as a black, sticky residue on decks, cars, patio furniture, and lower plants beneath infested trees.
What You Can Do on Your Property
The simplest and most effective step is destroying egg masses from fall through early spring. Scrape them off any surface you find them on using a credit card, putty knife, or similar flat edge, and drop them into a bag or container with rubbing alcohol or hand sanitizer to kill them. Each egg mass you destroy eliminates 30 to 50 potential lanternflies.
During nymph and adult season, stomping them is genuinely encouraged by the state. Pennsylvania’s official guidance is blunt: squash them, smash them, just get rid of them. Circle traps wrapped around tree trunks can also catch large numbers of nymphs as they climb upward to feed. These traps use a funnel design that directs the insects into a collection container and are widely available at garden centers.
If you have tree of heaven on your property, consider removing female trees (the ones that produce seed clusters) while keeping one or two males as “trap trees” that attract lanternflies to a single location where they can be treated. Penn State Extension recommends this strategy to concentrate the population rather than scatter it across your yard.
When and How to Use Insecticides
For properties with heavy infestations, chemical treatment is an option, but timing matters significantly. Systemic insecticides, the kind that are absorbed by the tree and ingested when the insect feeds, work best against adults from July through September. Applying them too early means their effectiveness fades before the critical fall egg-laying period. These can be applied as a soil drench around the tree’s base or directly to the trunk.
Contact insecticides, which kill on direct application, work against both nymphs and adults but tend to have poor residual effect, meaning they don’t keep working after they dry. Organic-friendly options like neem oil, insecticidal soaps, and horticultural oils fall into this category. They require good activity but need reapplication.
One critical rule: never spray any insecticide on plants that are blooming. Systemic insecticides should only go on trees after flowering is completely finished, to protect bees and other pollinators. Only treat trees that spotted lanternflies actually feed on, since the insects need to ingest the chemical for it to work. Spraying a tree they ignore wastes product and kills beneficial insects for no reason.
Native Predators Are Starting to Help
There’s some encouraging news for Pittsburgh residents tired of fighting alone. Research from Penn State found that several native predators effectively feed on spotted lanternflies. Spined soldier bugs, a predatory stink bug native to North America, were the standout performers. In controlled tests, a group of eight spined soldier bugs consumed every lanternfly in an enclosure within three to four days, regardless of life stage. Carolina and Chinese mantises were also effective predators.
These findings came partly from a community science project that collected nearly 2,000 reports from Pennsylvania residents who photographed birds and insects feeding on spotted lanternflies between 2020 and 2022. The predators ate lanternflies no matter what host plant the lanternflies had been feeding on, which matters because some researchers had wondered whether chemicals from tree of heaven might make them unpalatable.
In their native range in Southeast Asia, parasitic wasps keep spotted lanternfly populations in check. Importing those wasps to the U.S. requires extensive environmental impact studies, which are currently underway through the USDA and university researchers, but no releases have been approved yet.
How to Report Sightings
If you spot lanternflies outside the known quarantine zone, reporting is especially important. You can file a report online through the Pennsylvania Department of Agriculture’s website or call 1-888-4BADFLY (1-888-422-3359). Even within Allegheny County, reporting helps the state track population density and spread patterns. The state’s interactive quarantine map lets you check whether your specific location falls inside the current quarantine boundary.
For Pittsburgh residents, the practical reality is that spotted lanternflies are here and established. The combination of scraping egg masses in winter, killing nymphs and adults through spring and summer, and targeted insecticide use on heavily infested trees is the current best approach to keeping populations manageable on your property.