Spotted lanternflies are named after flies, look like moths, but are actually planthoppers. They have piercing-sucking mouthparts which allow them to drill into the phloem of a plant to feed directly on the sugary sap—which comes out their other end as sticky, sweet honeydew.
This planthopper is thought to have arrived as egg masses on a stone shipment in 2012. The first infestation was found in Berks County, Pennsylvania in 2014 in a wooded area of Ailanthus altissima, the Tree of Heaven. Despite a quarantine of the townships involved, and efforts to eradicate this pest, the spotted lanternfly has proved difficult to contain and its range now includes infestations in New York.
The name lanternfly is misleading; spotted lanternflies have little in common with any type of fly. Another misconception arises when viewing adults with wings spread, making them look like moths. Spotted lanternflies are planthoppers in the order Hemiptera, or true bugs, and are more closely related to cicadas, brown marmorated stink bugs, aphids, and leafhoppers.
The first instar nymphs are active from May until July and are approximately ¼” long and black with white spots. They are occasionally mistaken for ticks. Second and third instar nymphs are also black with white spots.
Fourth instar nymphs take on a red coloration with white spots and can be up to ¾”. This stage is active from July through mid-August; they then molt and become adults. All nymphal stages and adult spotted lanternflies can use their powerful hind legs to jump impressive distances.
Many photos show adult SLF with their wings open, including the red underwings, but in nature this only occurs when the SLF is startled or is ready to take flight. It is much more common to see the 1" adults at rest with black-spotted, pinkish-tan wings folded over their backs. Both male and female SLF have yellow abdomens with black stripes.
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Spotted lanternflies do not bite or sting. They feed exclusively on plants outdoors and can only survive for about 48 hours without feeding on a plant. In natural and residential areas, they feed on Tree of heaven (Ailanthus), black walnut, maples (they will preferentially feed on silver maple, then red maple), willow, river birch, black cherry, tulip poplar, and other trees. Like agricultural crops (with the exception of grapes), they do not appear to be damaging trees. They can, however, be a nuisance because of their sheer numbers.
Because spotted lanternfly, a phloem feeder, consumes large quantities of a plant's sugary sap to extract nitrogen and amino acids, it expels large quantities of excess sugar-water (honeydew). Honeydew—often misidentified as sap—shows up on outdoor equipment, decking, and vehicles as well as pets and your clothing and hair. Left to accumulate outdoors, honeydew acts as a growth medium for thin, dark layers of sooty mold fungi. Bees and wasps are also attracted to the sweetness, so there can be an increased stinging risk around infested plants.
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Spotted lanternfly has proven to be a serious pest of grapes (both cultivated and wild). They are swarm feeders and up to 400 SLF adults per vine have been reported. Feeding by a population this high has been shown to weaken the vine, leading to loss of winter hardiness, reduced or no return bloom or crop, and even vine death. They don't seem to be causing significant damage to agricultural crops like hops, apples, or peaches, but the issue is still being studied.
Spotted lanternflies are common hitchhikers at all life stages, but adults and egg masses are most commonly moved. Adults will fly into open windows of vehicles, into picking bins, and into the back of trucks while they are being loaded; eggs can be found on almost any outdoor surface. Transportation by human activity is the most common form of movement and the main reason SLF populations have spread significant distances.
Moving an outdoor item that unknowingly has an egg mass to a new location is a common way spotted lanternflies spread to a new location. Common items on which egg masses have been laid include firewood, motor homes, recreational vehicles, building materials, and even kiddie pools. To reduce the risk of these hitchhiking pests, the NYSIPM Program has created a SLF Checklist to use when visiting an area with known populations of SLF.
If it is not known to occur in your area or you're not sure if it does, we want to know about it! Send an email with location information and photos to: firstname.lastname@example.org.
Early detections are especially important to help protect agricultural crops that might be affected.
Traps can be useful to catch the SLF nymphs and adults as they climb the tree trunk. The traps are best set by early May to capture the nymphs as they emerge from the egg masses. Although the traps may catch large numbers of the insects it will not completely prevent SLF's presence on that tree. Many egg masses could have been laid in the tree canopy above the trap, and the adult stage can fly into the higher branches without climbing the trunk.
Sticky Band Traps - These traps encircling the trunk can be effective but they must be accompanied by a barrier to prevent the capture of beneficial insects and animals such as birds. A piece of vinyl window screening secured above the sticky band, secured with push pins at the top and flared out at the bottom several inches below the band can help prevent unintentional catches of other insects and birds.
Circle Traps - These traps consist of screening that encircles the trunk which funnels climbing spotted lanternflies into a container at the top from which they cannot escape. Our friends at Penn State created a detailed guide on how to build a circle trap.
Since spotted lanternflies rarely cause damage to landscape trees, treatment is not necessary for the health of the tree; but if they become a nuisance insecticides can be used. Some people may choose to hire a certified pesticide applicator who is equipped to make a tree injection, bark sprays or soil drenches. There are a few pesticide products labeled for use by residents in New York. They can be found at the bottom of a downloadable table here.
For safe and legal applications, it is always important to read and follow the product label before applying any pesticide.
Scraping Egg Masses - Late fall, after spotted lanternflies are killed by freezing temperatures and before they hatch in May, is a good time to look for and remove egg masses. Check for the egg masses on tree trunks, branches, rocks, lawn furniture, and really anything that's outside. The egg masses are often found on the underside of branches or objects and vary in size but typically are about 1 1/2" long and and 3/4" wide and look like grayish splotches of mud or putty. Scrape these egg masses into a re-sealable bag which contains rubbing alcohol or hand sanitizer and dispose of them in the solution to be assured they will not hatch.
Because spotted lanterflies lay many egg masses high up in tree canopies, removing egg masses within reach will not eliminate them, but because each egg mass contains up to 50 eggs, it can reduce the numbers, especially early in the season.