The Spotted Lanternfly (SLF), Lycorma delicatula, is an invasive planthopper native to Asia, first detected in the United States in Pennsylvania in 2014. It has since spread across multiple states, causing concern due to its wide-ranging appetite for various plants. The definitive answer is that the Spotted Lanternfly is not dangerous to humans or pets through biting, stinging, or toxicity.
Assessing Immediate Danger to Humans and Pets
The Spotted Lanternfly poses no direct physical threat to people or household animals. It lacks a stinger and the mouthparts necessary to bite humans or pets. As a planthopper, its mouth is adapted only for piercing plant tissue to suck out sap. Furthermore, there is no evidence that the SLF transmits any known human or animal pathogens.
Concerns about toxicity, particularly if a pet or child were to ingest one, are generally low. While the SLF is not poisonous, its bright coloration (red and black on its hindwings and nymphs) is a form of aposematism. This warning signal suggests to predators that the insect may be unpalatable, likely due to compounds sequestered from its preferred host plant, the invasive tree-of-heaven (Ailanthus altissima). Although ingestion is not recommended, the risk of serious poisoning is minimal for pets and children.
The main nuisance the SLF creates for people is indirect, stemming from its waste product, “honeydew.” When large numbers feed, they excrete copious amounts of this sticky, sugary liquid that coats decks, outdoor furniture, and play equipment. This honeydew becomes a medium for the growth of black, sooty mold. While the sooty mold is harmless to most people, the fermenting honeydew attracts other nuisance insects, such as wasps and bees, which increases the stinging risk near infested plants.
The Actual Threat to Ecosystems and Commerce
The true danger of the Spotted Lanternfly is its devastating impact on agriculture and native ecosystems, particularly high-value crops and trees. The insect is a generalist feeder, consuming sap from over 70 different plant species, including valuable trees and fruit trees. While its preferred host is the invasive tree-of-heaven, it also targets economically significant plants like grapevines, hops, and stone fruits.
Feeding damage occurs when the SLF uses its straw-like mouthpart to penetrate the bark and siphon sugary sap from the plant’s vascular system. This constant draining weakens the host plant, leading to reduced photosynthesis, wilting, leaf curling, and branch dieback. In vineyards, massive swarms severely stress grapevines, reducing their winter hardiness and impacting fruit production. This poses a significant threat to the multi-billion dollar grape and wine industry.
The sheer volume of honeydew creates a secondary problem that harms plants and makes outdoor areas unusable. As the sooty mold grows on the honeydew-coated leaves and stems, it blocks sunlight. This inhibits the plant’s ability to photosynthesize, reducing crop viability and overall plant health. The economic impact of this pest has been estimated to cost hundreds of millions of dollars annually in lost crops and damages if its spread is not controlled.
Safe Identification and Eradication Methods
Controlling the Spotted Lanternfly requires understanding its life cycle: egg, nymph, and adult. Egg masses are laid in the late fall, typically containing 30 to 50 eggs. They appear as a gray, putty-like smear about an inch long on any smooth surface, including tree bark, outdoor equipment, or vehicles. Nymphs hatch in the spring and progress through four instars. Early stages are small and black with white spots, while the fourth instar is larger, about a half-inch long, and brightly colored red with black and white spots.
The most direct method for eradicating nymphs and adults is the “stomp and squish” technique. Adults are relatively poor flyers and mostly jump, making them easier to crush, especially if approached from the front. For egg masses, present from fall to spring, the recommended method is scraping them off the surface using a plastic card or putty knife. The scraped mass must then be immediately placed into a sealed bag or container filled with rubbing alcohol or hand sanitizer to ensure egg destruction before disposal.
It is important to inspect all outdoor items, such as vehicles, grills, and firewood, for egg masses and live insects before moving them. This is particularly crucial when traveling outside of an infested area to prevent the insect from hitchhiking to new locations. Reporting sightings to local agricultural or extension services is encouraged, especially if the insect is found in a new, uninfested area, as this information tracks the pest’s spread and informs official control measures.