Spotted lanternfly (Lycorma delicatula) or SLF, is an invasive insect pest from Asia that primarily feeds on trees of heaven (Alianthus altissima) but can also feed on a wide variety of plants such as grapevine, hops, maple, walnut, and fruit trees. While the full impacts of SLF are unknown, the insect will negatively impact the agricultural and tourism industries and may impact New York's forests.
In the US, SLF was first discovered in Pennsylvania in 2014 and the first established population in New York State was discovered on Staten Island in August 2020. Visit the Cornell Integrated Pest Management site for an up-to-date map of current infestation locations in the Northeast, including New York.
Description
Nymphs, or newly hatched SLF, are black with white spots and turn red before transitioning into adults. The black nymphs can be seen as early as April through July. The late-stage red nymphs can be seen from July through September.
Adults begin to appear in July and are approximately 1 inch long and ½ inch wide at rest, with eye-catching wings. Their forewings are grayish with black spots. The lower portions of their hindwings are red with black spots and the upper portions are dark with a white stripe.
In the fall, adults lay egg masses on nearly anything from tree trunks and rocks to vehicles and firewood. The egg masses are usually are smooth and brownish-gray with a shiny, waxy coating when first laid. Though it is common to see them with the waxy covering, sometimes SLF will lay eggs without them.
Signs of an Infestation
- Sap oozing or weeping from tiny open wounds on tree trunks, which appears wet and may give off fermented odors.
- One-inch-long egg masses that are brownish-gray, waxy and mud-like when new. Old egg masses are brown and scaly and do not have the waxy coating.
- SLF excrete liquid waste called honeydew that builds up under plants, sometimes encouraging the growth of black sooty mold.
Impacts
SLF pose a significant threat to New York's agricultural industry, negatively impacts outdoor recreation, and may impact forest health.
- Adults and nymphs use their sucking mouthparts to feed on the sap of more than 70 plant species.
- This feeding, sometimes by thousands of SLF, stresses plants, making them vulnerable to disease and attacks from other insects.
- SLF also excrete large amounts of sticky "honeydew", which:
- promotes the growth of sooty molds that interfere with plant photosynthesis, negatively affecting the growth and fruit yield of plants;
- attracts swarms of insects that hinder outdoor activities; and
- results in people getting honeydew on their hair, clothes, and other belongings when going outside.
SLF has the potential to damage multiple agricultural crops in New York. SLF is a pest of apples, grapes, hops, maple, walnut, and others. The full extent of economic damage this insect could cause is unknown at this time.
Spread
SLF spread primarily through human activity. They lay their eggs on vehicles, firewood, outdoor furniture, and stone, which are inadvertently transported to new areas, causing the insect to spread. All mobile stages of SLF are known to “hitchhike” on vehicles and clothing, also contributing to the spread.
Management
DEC is collaborating with the NYS Department of Agriculture and Markets and the US Department of Agriculture in efforts to address SLF. DEC continues to collect information about the location and spread of SLF but does not actively manage infestations because SLF has spread throughout many locations in New York State. However, there are steps landowners can take to manage SLF on their property.
Manage SLF on Your Property
The Cornell Integrated Pest Management program has information on how you can manage SLF if you find it on your property, including how to destroy egg masses, how to prevent them from spreading, and different ways to kill the bugs that you find.
- Learn how to identify SLF.
- Inspect outdoor items such as firewood, vehicles, and furniture for egg masses.
- If you visit places with SLF, be sure to check all equipment and gear before leaving. Scrape off any egg masses.
- Destroy egg masses by scraping them into a bucket of hot, soapy water or a baggie/jar of hand sanitizer.
How You Can Help
Report SLF
SLF is widespread in certain areas of New York State including Long Island, New York City, Hudson Valley, Capital Region, Finger Lakes, and Western New York regions. Check the AGM SLF webpage’s “Take Action” section for locations that SLF reports are needed.
