Spotted Lanternflies: How to ID and Manage Them in the Garden

Whether you’re already seeing spotted lanternflies at home or anticipate that they may spread to your region soon, you’re probably wondering about these invasive pests. Exactly how detrimental are they to the garden? Are they dangerous? What do they look like, and how do I manage them? Plant biologist Emily Estep will give you all the basics on spotted lanternflies, including how to ID them during their multiple stages and how to manage them in the garden.

The Spotted Lanternfly features a smooth, elongated body with a mottled appearance, characterized by an intricate design of black spots and a pair of strikingly colorful wings.

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Spotted lanternflies (Lycorma delicatula) are invasive, winged insects that are causing significant damage to agricultural crops and fields. So, what does that mean for your backyard garden?

If you’re in Pennsylvania, New Jersey, Delaware, or Maryland, you’re already familiar with this invasive species. If you’re in a neighboring state, unfortunately, it may only be a matter of time before they’re on your doorstep.

Whenever there’s a new invasive pest on the scene, there’s a lot of hubbub and concern among gardeners, and for good reason. Luckily, these insects aren’t that big of a deal on a backyard garden scale, though it’s still important to manage them properly.

These pests have a unique appearance that makes them easy to identify, and the steps you’re meant to take in your backyard if you see them aren’t too complicated, either. We’ve gathered all the information you need to ID and manage spotted lanternflies in the garden.

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What Are They

Close-up of a swarm of pests possessing slender bodies with grayish-brown bases covered in black spots, and their striking wings display vibrant red hues with dark tips when spread.
These pests can damage plants but aren’t harmful to pets.

Before we discuss how to identify and manage spotted lanternflies in the garden, let’s talk a little bit about this insect’s history in the United States, its impact on plants, and the severity of the issue.

While spotted lanternflies are absolutely invasive and problematic, it’s important to note up front that they do not pose a danger to people or pets. Though they can cause significant crop yield loss on an agricultural level, their feeding does not kill plants—besides grapes.

The first detection of these pests in the United States was in 2014 in Berks County, Pennsylvania. They have spread through much of Pennsylvania, all of New Jersey, all of Delaware, most of Maryland, and throughout the neighboring states, as far west as Illinois.

Cornell University is providing an updated map of spotted lanternfly sightings by county. You can use this map to see if these insects are in your neck of the woods or are approaching.

These insects are native to China and Vietnam. Despite an initial quarantine in Pennsylvania, they spread to neighboring states and continue to do so. Individual states are attempting their own quarantines and have different regulations to combat the spread.

For home gardeners, these lanternflies are more of a nuisance than a true problem. They feed on plant phloem (sap), a practice that does not kill plants on its own. However, it can seriously damage plants, stunting their growth and leading to disease.

Both the adults and nymphs suck the sap from plant stems and trunks. They feed on many different types of plants, including varieties of apples, stone fruits, oaks, and pines. The wounds from this process make plants more susceptible to disease and pathogens, and if there is enough damage to the tissue, it can stunt growth.

Additionally, spotted lanternflies produce honeydew, just like aphids. “Honeydew” refers to a sticky, sweet waste that these insects leave behind. It both attracts other pests and leads to sooty mold, a fungal disease that inhibits photosynthesis, also stunting growth.

Honeydew also attracts wasps. If you have a significant infestation of these invasive insects, tread lightly to avoid wasp stings.

Spotted lanternflies love to both eat and reproduce on tree-of-heaven (Ailanthus altissima), which is another invasive species that has already spread across most of the United States. Removing tree-of-heaven from your land is more important than ever since it appears to be a favorite breeding ground for this invasive species. 

Note that while these insects have piercing mouthparts that enable them to access plant sap, they do not bite or sting. They are not venomous, and there is currently no evidence that shows they are poisonous to dogs or cats. 

Though these invasive insects won’t mean certain death in your garden and won’t harm you, your family, or your pets, it’s still crucial that we do what we can to identify and manage them. Invasive species can be harmful to the environment, the economy, and much more if left unchecked.

How to Identify

This pest's body is sleek and slender, exhibiting a mix of dark, grayish tones and unique black spots, while its expansive wings feature a vivid red hue that stands out against its muted exterior.
Identifying this pest requires knowledge of its life stages.

Spotted lanternflies are fairly distinct-looking and easy to identify. However, they have three major life cycle stages (early nymphs, late nymphs, and adults) in which they look different. You need to know what they look like at each stage to be able to identify this invasive pest.

Their common name is not very helpful. Though they’re always spotted, they do not resemble flies. Their large wings are much more similar to the appearance of a moth than a fly. Additionally, they do not light up like a lantern. The word actually refers to their long sap-sucking snouts, which are called “lanterns.”

Upon hatching, these insects are considered early-stage nymphs. The immature nymphs have black bodies with white spots, and they’re about ¼ inch long. This stage is most prevalent in spring and in mid-summer, between April and July.

There are actually multiple sub-stages of early-stage nymphs, but they’re all black with white spots. These early-stage nymphs are often mistaken for ticks due to their somewhat rounded appearance and small size.

Late-stage nymphs change color. They are now mostly red, instead of black, maintaining their white spots. You will most likely find late-stage nymphs in July and throughout the summer, into September. These nymphs are about ¾ inch in length but have not yet reached a full inch in size.

Finally, they evolve into adult lanternflies. You may see this stage as early as July and as late as November. Now about an inch long, the insects have developed two sets of wings. Long outer wings cover their inner wings and bodies. The outer wings are slightly gray or light pink in color, with half covered in black dots and half covered in a brick pattern.

The inner wings have patches of red, white, and black. They have the same shade of red that was present on the bodies of the late-stage nymphs. Their legs and heads are black, while their abdomens are yellow with black stripes.

With so many layers of colors and patterns, they’re very distinctive. Note that, usually, you will see them with their outer wings folded over their backs, covering a lot of the details. If the wings are expanded, they’re about two inches wide.

Additionally, you may also want to keep an eye out for their egg masses. Adult females lay eggs mostly in the fall. The egg masses overwinter, and the next generation hatches in spring. You may find them on any flat surface, from a tree to outdoor furniture.

They lay their eggs in 1-inch rows, and the eggs have a muddy-looking covering that conceals them slightly. Over time, the “mud” dries out and cracks, so you may be able to see the specific eggs underneath. Depending on the color and texture of the surface these egg masses are attached to, they may be obvious or totally camouflaged.

With the knowledge of what they look like at all stages, including their egg masses, you should be able to identify spotted lanternflies easily. If you discover sooty mold on your plants, this could also indicate that the invasive insects are around.

How to Manage

The pest rests on a wet leaf, showcasing a distinctive body with a dark grayish-brown base adorned with prominent black spots and vibrant red hindwings.
Report sightings promptly to help track these pests.

If you see spotted lanternflies on your property, report it. Research how to do so in your specific state. Most states have phone numbers or online resources that make it easy to report these invasive insects. This is an important step that allows local authorities to track the spread.

Next, don’t panic. Remind yourself that these flying bugs can’t hurt you and usually only cause minimal damage to plants. While it’s important that you report and handle them properly, there is no cause for alarm.

In your gardens and within your yard, experts advise that you physically kill any spotted lanternfly populations that you can easily reach. Otherwise, leave them be, and hope that natural predators do their job.

You can step on them with shoes or crush them in your hands, preferably while wearing gloves. If destroying them in this way makes you uncomfortable, you can catch them and put them in a glass of soapy water or rubbing alcohol, which will also kill them.

If you see an egg mass, you can manually crush it. You can also scrape it off the surface and submerge it in a bag of rubbing alcohol, which will kill the eggs.

Do not spray infestations, plants, or outdoor surfaces in your yard with insecticides, chemicals, or home remedies like white vinegar. Simply put, it won’t make a dent in the spotted lanternfly population, but it will harm beneficial insects, including pollinators and potential spotted lanternfly predators.

In fact, biological control is an important tool against these insects. Spiders, praying mantids, birds, and more will eat these pests. It’s important that we don’t harm these natural predators in our attempt to control their prey.

While it may be tempting to take an aggressive approach against this invasive pest, they are simply not important enough to risk the damage to beneficial wildlife. It’s also unlikely to be very effective at stopping such a vigorous insect.

If you discover them on your ornamental plants or edible crops, you can try spraying them with a harsh stream of water. You can also try building a circle trap, as detailed by PennState Extension. You can even use a shop vacuum to suck up the insects and then discard them.

To protect vulnerable garden crops, particularly grapes, cover them with fine mesh netting. Make sure the netting is secured along the edges, otherwise the insects may gain entry. 

Otherwise, do what you can to provide ideal conditions for your plants. Make sure they are getting enough sunlight, water, and nutrients. Stay on top of any other pest and disease issues that emerge. Healthy plants will put up a better fight against the invasive spotted lanternfly.

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