Spotted lanternfly (Lycorma delicatula) is a non-native, invasive insect first seen in September 2014 in Berks County, PA, when a shipment of stone arrived from China with the eggs attached. The insect is native to China, India, Japan, Korea, and Vietnam. By 2017, the insect moved to 13 Pennsylvania counties and a single county in both Delaware and New York. It is highly invasive, has a wide host range, and lacks natural, native enemies. To date, spotted lanternfly, also known as SLF, has been identified in 11 states: New York, Maryland, Virginia, West Virginia, Pennsylvania, Massachusetts, Ohio, Connecticut, Delaware, Indiana, and New Jersey.
“It is only a matter of time until we see an infestation but now we see the hitchhikers,” said Adria Bordas, Fairfax County’s Virginia Cooperative Extension (VCE) agent for horticulture.
SLF is a sap eater. The insect punctures the plant, sucks the plant sap, and excretes a sugary substance called honeydew. Honeydew attracts other insects and creates a sweet substrate for sooty mold. The dark, sooty mold is not harmful but coats the leaf surface, reduces photosynthesis, and discolors the plant. Plants are weakened from lack of sap but also from coated leaves.
SLF can significantly damage agricultural crops such as grapes, hops, and fruit trees and the logging industry. Because they are heavy sap feeders, they are not as attracted to homeowners’ garden annuals, perennials, and vegetables. However, SLF can infest homeowners’ properties, damage ornamental trees, and attract other unwanted pests.
“This is a piercing, sucking insect,” said Mark Sutphin, VCE agent for horticulture in Frederick County, VA. The SLF is well established in Frederick County. “A tree trunk could be covered by many insects, each creating so many puncture wounds that the tree oozes. You may see a white yeasty growth. Also, the honeydew attracts stinging wasps and hornets, which you would not want near a play area.”
The insect itself cannot hurt a person, it cannot bite or sting. It only has one life cycle and although eggs remain through winter, the adults die with frost. “Unlike stink bugs, the SLF adults do not try to come into the house to overwinter,” said Mark. “However, they may be attracted to chimneys and come in the house via the flue.”
SLF feeds on more than 100 known host plants and particularly likes the tree of heaven (Ailanthus altissima), which is an invasive weed species. Homeowners are encouraged to remove the tree but may have to use herbicides. Tree of heaven sprouts again from the root so just chopping it down may not eliminate it.
One of the pest management challenges is that the SLF goes through several stages of growth, each of which looks dramatically different. Adults are about an inch long and half inch wide, almost like a gray moth. It has four wings, but it is not a strong flyer. The forewings are two-toned gray. The part closer to the head is a light gray with dark spots and there is a band of dark gray toward the wing tips. The hind wings are red, white, and black. The body is yellow and black. Because they are poor flyers, they hop or run, flashing their bright red hind wings to ward off predators. Adults appear in July and as they die in the fall with frost, they fall to the ground or stay stuck on tree trunks.
By the time the adults have died, the females have laid an egg mass of about 30 to 50 eggs, which are covered with a gray, waxy coating. These appear on vertical surfaces that do not have to be plant material, could be part of the house or deck.
In the spring, the eggs hatch to reveal young nymphs that are black with white spots, which later molt to have bright red coloring with black markings and white spots. In the summer, they molt to become the adult.
There are no pesticides on the market and there are no known native predators. So what can a homeowner do to prevent this insect from becoming an infestation? Plenty and everyone, from children to adults, can get involved and learn more in order to prevent the spread of this insect. Here are some ideas:
- Learn what the SLF looks like in all stages of growth
- Remove tree of heaven trees or put a sticky band around the trunk to trap the nymphs. If using sticky bands, cover with wire mesh or screening to minimize catching birds and other small vertebrates.
- Report sightings to the local extension agent or the state department of agriculture
- Remove or kill the SLF. If it is the egg mass, smash or scrape and put in a bag with a little bit of rubbing alcohol or hand sanitizer.
- If not sure what the insect is or if the tree is a tree of heaven, bring a sample or take a photo and show the extension agent
- Examine the trees, decks, sides of houses, picnic tables, grills, trailers, campers, etc. to identify SLF. If planning to move an item such as the camper, look before travel so don’t bring the SLF to another county or state.
- Ask a master gardener or extension agent to give a presentation about SLF at local gardening clubs, youth groups, naturalist groups, scout troops, schools, camping organizations, etc. to increase awareness and spread the word.
Before COVID-19, when we had in person events, I saw tables at events where master gardeners and extension agents distributed brochures, coasters, and posters about SLF. People even got dressed up in an adult SLF costume to demonstrate how one looks. “We have distributed so many wallet cards,” said Mark. “People are on the lookout, so that is good,” said Adria.
States that have been impacted by this insect have developed a SLF specific website with information, resources, and the reporting process. The New York State Integrated Pest Management maintains a map of northeastern states with SLF sightings, as well as resources. For more information on SLF in your state, either contact the local extension agent or the state agriculture department. Here are links to state agricultural departments for the immediate area.
All photos courtesy of Mark Sutphin, Virginia Cooperative Extension