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 was found in New York in 2020.
The first New York State infestation was discovered in Staten Island in August 2020. Visit Cornell's Integrated Pest Management site for an up-to-date map of current infestation locations in the Northeast, including New York.
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 and until July. Red nymphs can be seen from July until 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 1-inch-long egg masses on nearly anything from tree trunks and rocks to vehicles and firewood. They are smooth and brownish-gray with a shiny, waxy coating when first laid.
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.
- SLF excrete liquid waste called honeydew that builds up under plants, sometimes encouraging the growth of black sooty mold.
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, stressed 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.
New York's annual yield of apples and grapes has a combined value of more than $350 million, which could be greatly impacted by SLF. The full extent of economic damage this insect could cause is unknown at this time.
SLF spread primarily through human activity. They lay their eggs on vehicles, firewood, outdoor furniture, stone, and which are inadvertently transported to new areas, causing the insect to spread.
DEC is working with the Department of Agriculture and Markets (AGM) and the US Department of Agriculture (USDA) to address SLF. Since it is less expensive and easier to deal with a pest before it becomes widespread, the goal is to find and treat SLF infestations early.
A plan has been developed that describes how the agencies will detect and prevent further spread of SLF in New York. Extensive trapping surveys are being conducted in high-risk areas throughout the state as well as inspections of nursery stock, stone shipments, commercial transports, etc. DEC and partner organizations encourage everyone to be on the lookout for this pest.
To slow the spread of SLF, AGM issued a quarantine that restricts the movement of goods brought into New York from quarantined areas in Delaware, New Jersey, Pennsylvania, Maryland, and Virginia. The quarantine requires regulated articles, such as packing materials, landscaping and construction equipment, and nursery stock to have certificates of inspection issued from the impacted states. Inspections are being conducted across New York by AGM and its partners to check for SLF and compliance with the regulations. For more information and for a list of regulated articles, see AGM's website.
In an effort to detect SLF early and respond in a timely manner, DEC has established a Protective Zone encompassing 20 counties located near the PA and NJ infestations. Protective Zones allow DEC and its partners to conduct activities such as surveying, monitoring, and management to find and prevent the spread of SLF. Protective Zones are established in the following counties: Bronx, Broome, Chemung, Chenango, Delaware, Dutchess, Greene, Kings, Nassau, Orange, Otsego, Putnam, Queens, Richmond, Rockland, Suffolk, Sullivan, Tioga, Ulster and Westchester.
How You Can Help
- Learn how to identify SLF.
- Inspect outdoor items such as firewood, vehicles, and furniture for egg masses.
- If you visit other states 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.
If you live outside New York City, Westchester, Nassau or Rockland county, you can help by reporting SLF immediately after it is found. Follow these steps:
- Take pictures of the insect, egg masses and/or infestation signs as described above (include something for scale such as a coin or ruler) and email to [email protected].
- Note the location (address, intersecting roads, landmarks or GPS coordinates).
After you have reported SLF in your area and collected a sample, you should kill any additional SLF you see by stepping on it or crushing it.