The spotted lanternfly (Lycorma delicatula) is an invasive insect known for its rapid spread and potential impact. This planthopper, originally from Asia, was first detected in the United States in Pennsylvania in 2014 and has since spread to numerous states. Many people are curious about whether this pest poses a threat to humans, animals, or the environment. Understanding its true nature is important for effective management.
Threat to Humans and Animals
The spotted lanternfly does not pose a direct threat to the health of humans or animals. These insects do not bite or sting, nor do they transmit diseases to people or pets. Their mouthparts are designed for piercing plants and sucking sap, and they are not capable of penetrating human or animal skin.
While the insects themselves are not poisonous if ingested by pets, there is currently no definitive evidence to support claims of toxicity. However, consuming large quantities of any insect with a tough exoskeleton can be difficult for animals to digest. The primary nuisance to humans and animals comes from the sticky, sugary substance they excrete, known as honeydew. This honeydew can accumulate on surfaces, making them messy and attracting other insects like ants, bees, and wasps.
Impact on Plants and Ecosystems
The spotted lanternfly presents a major threat to plants and agricultural industries. This insect feeds by piercing plant stems and trunks with its mouthparts to extract sap, which weakens the host plant. They feed on a wide variety of plants, with over 70 species documented as hosts, including economically important crops and trees.
Key host plants include grapevines, fruit trees (such as apple, peach, and plum), hops, and hardwoods like maple, black walnut, willow, and birch. Their feeding leads to large amounts of honeydew, which promotes black sooty mold growth on affected plants. This mold blocks photosynthesis and reduces plant vigor.
Damage to plants can include reduced growth, stunted development, and decreased crop yields. In vineyards, heavy infestations can weaken grapevines, leading to reduced or no fruit production and even vine death. The presence of sooty mold can also make agricultural products unmarketable. The annual economic impact on agriculture and forestry in affected states, such as Pennsylvania, can be tens of millions of dollars.
Identifying and Preventing Spread
Recognizing the spotted lanternfly in its different life stages is important for managing its spread. Egg masses, laid in fall, are typically covered with a grayish, mud-like coating and contain 30-50 eggs. They can be found on various surfaces, including tree trunks, rocks, outdoor furniture, and vehicles.
Nymphs, hatching in spring, are initially black with white spots, developing red patches before maturing into adults. Adults are about an inch long, with gray forewings covered in black spots and distinctive red hindwings visible when spread.
This insect primarily spreads over long distances through human activity. Egg masses, nymphs, and adults can hitchhike on vehicles, outdoor equipment, firewood, and other items. To prevent accidental transport, inspect vehicles, outdoor equipment, and any items moved from an infested area.
Reporting and Management
If a spotted lanternfly is sighted, especially outside known infested areas, report it to local agricultural departments or extension offices. This helps authorities track spread and implement control measures. For individual insects, the general advice is often to “squash on sight.”
Management efforts include removing Tree of Heaven (Ailanthus altissima), a preferred host plant and an invasive species itself. While its removal helps, the spotted lanternfly feeds on many other plant species. Other strategies involve destroying egg masses by scraping and crushing them, or placing them in a container with rubbing alcohol or hand sanitizer. Integrated pest management (IPM) strategies, including physical traps or targeted insecticide applications, are used to manage populations.