The spotted lanternfly (Lycorma delicatula) is an invasive insect species, originally from Asia, first detected in the United States in Pennsylvania in 2014. It has since become established across the eastern United States. Adults are about an inch long, with gray, black-spotted forewings and red hindwings visible in flight. Their spread is often accidental, as they lay egg masses on surfaces like vehicles and outdoor furniture, which can be transported.
Interaction with Humans
Spotted lanternflies do not bite or sting humans. Their mouthparts are designed for piercing and sucking sap from plants, functioning like a tiny straw to extract nutrients. They cannot penetrate human or animal skin.
There is no evidence they are venomous or transmit diseases to humans or pets. While their legs have fine hairs that might cause mild, temporary skin irritation upon contact, this is not a bite. The primary nuisance to humans comes from their large populations and the sticky substance they excrete, not direct physical harm.
Impact on Plants and Environment
While not a direct threat to humans, spotted lanternflies cause considerable harm to plants and the environment. They feed by inserting their mouthparts into plants to suck out sap. This feeding weakens the host plant, draining its energy and making it susceptible to other stressors like disease.
As they feed, spotted lanternflies excrete a sugary, sticky liquid called “honeydew.” This honeydew accumulates on plant surfaces and objects below, attracting other insects like ants and wasps. It also promotes the growth of black sooty mold, which covers leaves and branches. Sooty mold reduces a plant’s ability to photosynthesize by blocking sunlight, compromising its health.
Spotted lanternflies infest over 70 plant species, including economically important crops and native trees. They threaten agricultural industries, especially vineyards, fruit trees (like apple and cherry), and hops farms. Native trees such as maple, walnut, and willow are also affected, with heavy infestations sometimes leading to reduced yield or plant death, particularly for grapevines.
Taking Action Against Them
If spotted lanternflies are observed, especially in areas where they are not yet widely established, reporting sightings to local agricultural departments or extension offices helps track their spread. Some states, however, no longer require reports once populations are detected throughout.
For direct management, several simple methods can be employed:
- Crush or stomp individual lanternflies.
- Spray larger numbers with a mixture of water and dish soap, vinegar, or rubbing alcohol.
- Use sticky traps on tree trunks to capture nymphs and adults. Add a barrier like screening to prevent non-target animals from getting caught.
- Scrape off egg masses, found on various surfaces, and dispose of them in alcohol or hand sanitizer to reduce future populations.