The spotted lanternfly, Lycorma delicatula, is an invasive insect first detected in the United States in Pennsylvania in 2014. Native to parts of China, India, and Vietnam, this planthopper likely arrived as egg masses on imported goods. Since its discovery, it has rapidly spread across several states, posing a significant threat to agricultural and natural ecosystems.
Danger to Humans and Pets
Spotted lanternflies do not pose a direct threat to human health or domestic animals. They do not bite or sting people or pets. Their mouthparts are designed for piercing and sucking sap from plants and cannot penetrate human or animal skin.
While these insects do not transmit diseases to humans or pets, some veterinarians report that pets consuming them might experience an upset stomach, drooling, or loss of appetite.
Impact on Plants and Agriculture
The primary concern with spotted lanternflies stems from their feeding habits and the extensive damage they inflict on plants, especially those of agricultural importance. Both nymphs and adults feed by inserting their piercing-sucking mouthparts into plant phloem to extract large quantities of sap. This feeding weakens plants, stunts growth, reduces crop yields, and can contribute to plant death.
Spotted lanternflies infest a wide range of host plants, with over 70 species documented globally and at least 56 in North America. They are particularly damaging to economically important crops like grapevines, fruit trees (including apple, peach, and plum), and hops. Hardwood trees such as maple, walnut, oak, and willow are also vulnerable.
A significant consequence of their feeding is the excretion of “honeydew,” a sticky, sugary substance. This honeydew accumulates on the host plant and anything beneath it, attracting other insects like wasps, ants, and flies. It also promotes the growth of black sooty mold, which covers leaves, branches, and fruit. This mold reduces the plant’s ability to photosynthesize, impacting overall health and fruit quality, and leading to significant economic losses for agricultural industries.
Identifying Spotted Lanternflies
Adult spotted lanternflies are approximately one inch long and half an inch wide. Their forewings are light brown or gray with distinct black spots and a speckled band on the wing tips. When wings are open, bright red hind wings with black spots and white and black bars become visible. The abdomen is typically yellow with black bands.
Nymphs, or juvenile stages, undergo several changes in appearance. Early nymphs (first through third instars) are black with white spots and are wingless. As they develop into the fourth instar, they become noticeably larger, acquiring red patches in addition to the white spots, while remaining black. Nymphs are active from May through September.
Spotted lanternflies lay egg masses, usually containing 30 to 50 eggs, on various hard surfaces. These masses are about one inch long and are typically covered with a gray, putty-like, waxy coating when freshly laid. This covering dries over time, resembling a smear of cracked mud, which camouflages them. Egg masses can be found on tree trunks, branches, rocks, outdoor furniture, vehicles, and other smooth surfaces from fall through spring.
What to Do if You See Them
If you see an adult or nymph, kill it immediately, often called “squash on sight.” This can be done by crushing them with your foot or a suitable object.
Destroying egg masses is particularly impactful as it prevents future generations. Scrape egg masses off surfaces using a credit card, putty knife, or similar tool. Place the scraped eggs into a sealable plastic bag containing rubbing alcohol or hand sanitizer to ensure they are killed, then dispose of the sealed bag in the trash.
Reporting sightings to your state’s agricultural department or extension office is important, especially if you are outside a known quarantine zone. Provide the location, date, and, if possible, photographs of the insect or egg mass. This information helps authorities track the spread and implement control measures. Also, check vehicles, outdoor equipment, and any items stored outdoors for egg masses or live insects before traveling to prevent accidental spread.