The spotted lanternfly (Lycorma delicatula) is an invasive insect that arrived in the United States from Asia. This planthopper poses a significant threat to agriculture and forestry.
Are They Dangerous to People or Pets?
Spotted lanternflies are not dangerous to humans or pets. They do not bite, sting, or carry diseases that can be transmitted to people or animals. Their mouthparts are designed for piercing plants to feed on sap, meaning they cannot penetrate human or animal skin.
While no confirmed toxins have been found in spotted lanternflies, veterinarians have occasionally reported mild, temporary symptoms like upset stomachs, drooling, or loss of appetite in pets that have ingested them, similar to reactions from eating other non-food items. The primary nuisance to humans comes from the sticky honeydew they excrete, which can cover outdoor surfaces.
The True Threat: Damage to Plants
Spotted lanternflies primarily damage plants through their feeding habits. They use piercing-sucking mouthparts to extract sap from stems and trunks, weakening the host plant. This can lead to reduced vigor, oozing sap, wilting, and dieback of branches.
They feed on over 70 plant species, including economically important crops and trees. Grapevines, hops, fruit trees (like apple and peach), and hardwood trees (such as maple, oak, and willow) are particularly susceptible. Their preferred host is the invasive tree-of-heaven (Ailanthus altissima), but they feed on many others.
A major issue is the sugary liquid, “honeydew,” they excrete while feeding. This honeydew creates a sticky mess on plants and surfaces, promoting the growth of black sooty mold. Sooty mold interferes with photosynthesis, further stressing the plant and impacting fruit quality, which can make crops unmarketable. The combination of feeding damage and sooty mold growth can lead to significant economic losses for agricultural industries. For example, projected annual losses could reach hundreds of millions of dollars across agriculture and forestry in affected regions.
Identifying and Reporting Spotted Lanternflies
Recognizing spotted lanternflies at different life stages aids in management. Egg masses, laid from September through December, are about one inch and covered with a grayish, mud-like coating that dries to resemble cracked mud. These masses can be found on tree trunks, rocks, outdoor furniture, vehicles, and other hard surfaces.
Nymphs hatch in spring, appearing black with white spots in early stages. Fourth instars become distinctively red with black and white spots. Adult spotted lanternflies, emerging around July, are about an inch long with light grey-brown forewings covered in black spots and striking red hindwings visible when spread.
Reporting sightings to state agricultural departments or extension offices is important for tracking their spread and informing control efforts. Take a clear picture of the insect and note the location. If possible, kill the insect by squashing it or scraping egg masses into a sealed bag with hand sanitizer or rubbing alcohol before disposal.
Understanding Their Spread
The spotted lanternfly is native to China and Vietnam, first detected in the United States in Pennsylvania in 2014. It likely arrived via imported goods, such as egg masses on stone shipments. Since its initial detection, the insect has rapidly spread across multiple states.
Human activity is the main factor in their long-distance spread. Egg masses can be inadvertently transported on vehicles, outdoor equipment, firewood, and other items moved between locations. Adult and nymph lanternflies can also hitchhike on cars, trucks, and trains. This “hitchhiking” ability makes containment challenging and highlights the need for public awareness and inspection, especially when traveling from infested areas.