Spotted Lanternfly

Plants at risk  
Identification  
Life cycle and behavior 
Spread and response  
How to help  
Resources

Adult spotted lanternfly.

Spotted lanternfly fourth nymphal stage.  

The spotted lanternfly (Lycorma delicatula) is a non-native plant pest that poses a threat to Connecticut’s environment, residential areas, and agricultural interests. The spotted lanternfly (SLF) poses a considerable threat to agricultural plants, such as apples and grapes, and a mild threat to native hardwood trees in Connecticut. Both nymphs and adults of the SLF feed by sucking sap from the stems and leaves of host plants. Depending on the severity, this can weaken and damage the plant by reducing photosynthesis.

Spotted lanternfly (SLF) likely arrived in North America on goods imported from Asia. SLF is native to China, India, and Vietnam. The first detection in the United States was in Berks County, Pennsylvania in September 2014, and it has since spread to multiple states. In 2020, two small established populations of spotted lanternfly were found in Fairfield County, Connecticut. Since then, SLF has spread to multiple counties in Connecticut.  

Plants at risk 

Tree-of-heaven (Ailanthus altissima), an invasive tree that is the preferred host of the spotted lanternfly. 

The invasive tree-of-heaven (Ailanthus altissima) is the preferred host plant for SLF, but the insect also feeds on a wide range of crops and plants, including grapes, apples, hops, walnuts, and hardwood trees. Altogether, about 60 plant genera are known to be attacked by SLF in North America. Approximately 47% of Connecticut’s forest trees are considered potentially susceptible to SLF. This potential range of hosts is one of the reasons why SLF is of such great concern and may be so difficult to combat.    

To date, SLF has only killed sapling trees, sumac, grapevines, and tree-of-heaven during infestations. Healthy, established ornamental trees have no recorded mortality from SLF, though canopy dieback and plant health decline have been observed. A 2023 study from Penn State University showed that hardwood trees, including silver maple, river birch, and willow, survived with slowed growth rates after four years of direct SLF exposure.

Although SLF’s potential impact on Connecticut’s hardwood forests is manageable, its potential impact on Connecticut’s agricultural industry could be devastating.

The following are some of the SLF host species that can be found in Connecticut:

• Almond 
• Apple 
• Apricot 
• Beech
• Black and paper birch
• Black gum
• Cherry
• Dogwood
• Elm
• Grape
• Hop
• Linden
• Maple
• Nectarine
• Oak
• Peach
• Pignut and shagbark hickory
• Pine
• Plum
• Poplar
• Sassafras
• Serviceberry
• Sycamore
• Tree-of-heaven
• Tulip poplar
• Walnut
• White ash
• Willow

Identification 

The spotted lanternfly is a planthopper in the family Fulgoridae, known for its bright colors and pronounced snout-like head.

The adult is approximately 1 inch long and 1/2 inch wide with large, colorful wings. The front wings of the spotted lanternfly are light brown with black spots in the center. Their hind wings have contrasting red and black patches with a white band between them. The legs and head are black; the abdomen is yellow with broad black bands.

The three immature stages, called nymphs, are black with white spots. During the fourth and final nymphal stage, the developing insect has red patches and small wing pads. Only the adult stage has wings.

Adult and immature spotted lanternflies are easy to detect due to their relatively large size and bright coloration; however, visual evidence can also be used to identify an infestation. Evidence includes:

• Oozing: Plants ooze or weep with a fermented odor. This comes from the wounds inflicted by the extensive feeding of the SLF.
• Honeydew buildup: SLF feeding creates a sticky residue called "honeydew". SLFs group in large numbers to feed, resulting in significant honeydew excretion. Look for large amounts of honeydew on plants and on the ground beneath infested plants (note that this honeydew attracts other insects, and other insects, such as aphids, also excrete honeydew). The honeydew is sticky, unsightly, and hard to get rid of, which is why SLF poses such a problem to fruit farmers. The presence of honeydew can destroy the value of the crop.
• Sooty mold: Honeydew promotes the growth of a black mold called "sooty mold", which can further damage the plant by blocking photosynthesis.
• Egg mass: Masses are gray and clay-like at first and later become brown and cracked. They can be found on trees and other smooth surfaces, including bricks, stones, and dead plants.  

SLF egg masses on tree bark.

A walnut tree affected by SLF.

Sap trail from SLF feeding. 

Life cycle and behavior  

Spotted lanternfly life cycle. 

The life cycle of SLF includes eggs, nymphs, and adults. Depending on the time of year, a different life stage of the spotted lanternfly will be present.

SLF lays its eggs in the fall. Yellowish-brown eggs are laid in masses of 30 to 50. The egg masses are covered with a waxy, indistinct gray coating. Eggs hatch in the spring and early summer, and nymphs begin feeding on a wide range of host plants by sucking sap from young stems and leaves. Adults appear in late July and tend to focus their feeding on tree-of-heaven (Ailanthus altissima) and grapevine (Vitus vinifera).

Spread and response

As a nymph, SLF can walk or jump. As an adult, it can fly short distances. However, SLF is primarily a hitchhiking insect. SLF lays eggs on almost any surface, including vehicles, trailers, outdoor equipment, and patio furniture, and can be spread long distances when people move infested material.

USDA APHIS has developed a strategy to reduce the spread of SLF and warns that the spotted lanternfly can survive year-round in farmlands, forests, and urban areas in the northeastern United States.

Spotted lanternfly quarantine in Connecticut

The Connecticut Agricultural Experiment Station (CAES) has issued a Quarantine Order with defined restricted areas for the spotted lanternfly. The purpose of this quarantine is to slow the spread of SLF within the state. It provides Connecticut businesses with certification to transport regulated articles out of state and helps protect the state’s agricultural industries by suppressing, controlling, or eradicating spotted lanternfly infestations in regulated areas. The quarantine also uses inspection or compliance agreements to permit the movement of regulated articles that are not infested with spotted lanternfly.

How to help  

• Do not move any wood or other potentially infested material from the site if you think you have observed spotted lanternflies.
• Report potential sightings of this invasive pest. If you suspect you have found SLF, snap a picture of it and complete this SLF Reporting Form from the Connecticut Agricultural Experiment Station.
• Immediately kill any adult or immature spotted lanternflies you find.
• Check your vehicles for stowaways. Inspect your vehicles, trailers, and other items for SLF adults and egg masses when traveling through areas with known or suspected SLF populations. These insects are known to hitchhike on vehicles and even clothing.

For forests, the best defense against insect pests like the spotted lanternfly is resilient forest management that supports diverse species, age classes, and forest composition. For more information about the overall health of your forested land, contact your Service Forester.

Resources

Spotted Lanternfly | Animal and Plant Health Inspection Service

Connecticut Agricultural Experiment Station SLF Page

New York State Integrated Pest Management SLF Page

PennState Extension Spotted Lanternfly Page

Content last updated April 2026.