Beware of Hitchhiking Pests: Stop the Spread of Spotted Lanternflies

A Pretty Pest with a Bad Reputation

Native to China, Vietnam, and Taiwan, the SLF likely arrived in the United States as egg masses on a shipment of stone from China sometime in 2012.

Once established in their new environment, they revealed a striking appearance that belies their destructive nature: adults sport tan forewings dotted by black spots and red hindwings marked in black and white. Nymphs begin black with white spots and turn red as they mature.

From September through December, females lay egg masses that resemble gray, mud-like smears. Each holds 30 to 50 eggs that hatch in spring, producing nymphs that pass through four stages before adulthood in midsummer. After hatching, the young nymphs quickly disperse in search of food, climbing and hopping across plants as they feed and grow. By midsummer, they mature into adults and begin their most destructive phase.

Feeding Frenzy: A Nightmare for Grapes and Gardens

Though SLFs don’t bite or sting, their feeding habits can devastate plants. Using piercing-sucking mouthparts, they draw sap from stems and leaves, excreting a sticky waste called honeydew. This sugary coating attracts pests and fosters black sooty mold, a fungus that blocks sunlight and disrupts photosynthesis.

This frenzied feeding affects many plants including hardwood, fruit, and ornamental trees, as well as grapes and hops. The insects’ habits weaken plants, reduce fruit and flower yields, and can lead to death.

For grape growers, the threat is especially severe. Researchers at Cornell University have observed infestations exceeding 400 adults on a single vine, leading to die-off and economic loss. In Pennsylvania, damage and control efforts are estimated to cost up to $324 million annually.

The SLF’s preferred host, the invasive Tree of Heaven, helps them thrive in disturbed landscapes such as highway edges and city lots, displacing native species and altering habitats. In doing so, they indirectly harm the birds, bats, and reptiles that rely on those trees for food and shelter.

How They Hitch a Ride

SLFs are strong jumpers but weak fliers. Long-distance spread occurs when humans unknowingly move SLF eggs laid on vehicles, firewood, or even patio furniture.

To slow the spread, many states have established quarantine zones restricting the movement of potentially infested materials. Because most new outbreaks occur near transportation corridors, public awareness and vigilance are essential.

Small Actions, Big Impact

You can also play a role in helping to control the invasion. If you see one, kill it. Each insect destroyed helps slow the population growth.

Report sightings outside known zones to your local cooperative extension or state agriculture department. Before traveling, inspect vehicles, camping gear, and outdoor items for egg masses hidden in crevices. Cornell University’s “Stop the Spread” checklist offers practical guidance for travelers and homeowners.

Penn State Extension also provides plans for an easy “circle trap” made from mesh and recycled materials that targets SLFs without harming beneficial insects.

Cracking the Code to Contain the Swarm

Researchers across universities and federal agencies are testing biological control methods to curb SLF populations. Promising candidates include parasitic wasps such as Anastatus orientalis and Dryinus sinicus, which naturally attack SLF eggs and nymphs in Asia. These species are being evaluated in containment facilities to confirm they will not harm native ecosystems before any release occurs.

Scientists are also using environmental DNA (eDNA) sampling to detect SLF genetic traces in soil and water, allowing early identification of new infestations. Data from these efforts feed into the U.S. Department of Agriculture’s National Agricultural Pest Information System and its publicly available quarantine map, which help guide management and public reporting efforts.