Spotted Lanternfly FAQs for Connecticut

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What’s red, black and white and coming to Connecticut? Lycorma delicatula, the Spotted Lanternfly (SLF).

You may not have heard of it yet, but the Spotted Lanternfly is an extremely destructive planthopper native to Southeast Asia. The insect most likely arrived in the U.S. hidden in cargo, and now it’s spreading rapidly throughout the northeast and Atlantic states.

SLF damages or destroys trees, crops, and your garden plants by feeding on them, and adult insect swarms are a nuisance to people and property.

Spotted lanternflies on a plant in Connecticut

SLF has been documented in Pennsylvania since 2014, and is now found in New Jersey, Virginia, and Delaware. A single insect was found in Southbury, Connecticut in late 2019 and it’s likely that we can expect more to arrive this year.

Since the insect is poisonous and there are no natural predators here for this pest, controlling SLF populations is difficult. Keeping its numbers low and slowing its spread are the two methods being used, along with quarantine areas in PA and NJ.

Connecticut residents are urged to look for SLF and report any sightings to the state’s agricultural station at ReportSLF@ct.gov. Recording the location of an insect sighting is a key measure that helps state agricultural staff to document and predict the spread of this pest, and to more accurately plan control measures.

You can read more about SLF from Connecticut’s Environmental Protection Department here.

Why is the Spotted Lanternfly a Problem?

The Spotted Lanternfly damages and kills trees and plants by piercing their leaf, stem, and bark surfaces and sucking out sap. Depending on the plant and the infestation severity, plants are damaged, disfigured, or even killed.

Similar to aphids, SLF excretes honeydew which causes sooty mold to grow on bark and stems. Black or dark grey sooty mold is not only unattractive, it can also damage a tree’s health.

Grapes, hops, and tree fruits (including important Connecticut crops like apples, cherries, and peaches) are particularly susceptible to sooty mold, making SLF-infested fruits not commercially viable. As a result, the Connecticut Department of Energy and Environmental Protection warns that much of Connecticut’s agricultural industry could be devastated if SLF gains a foothold in our state.

What are the signs and symptoms of Spotted Lanternfly damage?

The most obvious indication that SLF is present is large clusters of them in trees and/or flying about. They tend to group together and feed on the same plants.

A group of spotted lanternflies on a tree's trunk

Spotted lanternflies congregate on the trunk of a tree

Wounds on trunks and branches made by SLF feeding often continue to weep or ooze sap. It may smell like it’s fermenting and will attract other insects, such as ants, bees, and wasps.

Spotted Lanternflies excrete honeydew when they feed, so look for sticky leaves and stems, as well as sticky surfaces beneath trees.

Black sooty mold often appears on surfaces covered in honeydew, so large amounts of it may be an sign that SLF is present. However, other insects, such as aphids, also produce honeydew so this alone shouldn’t be used as an indicator.

Over time, trees damaged by Spotted Lanternfly may have wilting and curling leaves, and show general decline.

What does the spotted lanternfly look like?

Photo of a spotted lanternfly from above, with its wings outstretched. Red and grey spotted areas are observable

Spotted Lanternflies can be easy to spot once you know what they look like

The adult-stage insect is easily identifiable by its colorful abdomen and wings. It is also the most important stage of the insect’s life, as it’s highly mobile and can reproduce.

Adult Spotted Lanternflies appear in late July. They’re about one inch long and ½-inch wide with large, colorful wings. The front wings of are light brown with black spots in the center, while the hind wings have contrasting patches of red and black with a white band in between. The adult SLF has a black head and legs; the abdomen is yellow with broad black bands.

Because they tend to congregate in huge swarms, adult SLFs are easy to spot. In areas with large populations, it can be difficult to avoid them while outdoors; they’re likely to get tangled in your hair and even fly into your mouth!

Before maturity, the SLF grows through 4 stages (or instars) and is referred to as a nymph (immature insect). In these immature stages, SLF is spotted but has no wings and does not fly. During the first three stages, nymphs are black with white spots. During the fourth and final immature stage, the developing insect adds red patches.

When should I be on the lookout for SLF?

Female lanternflies lay masses of 30 to 50 eggs in autumn (usually in September, depending on weather conditions). Individual eggs are yellowish-brown but the egg mass itself is covered by a gray, waxy coating that makes it difficult to spot. Check on smooth surfaces, including leaves, stones, decking, and even cars. You’ll also find egg masses on tree trunks, dead plants, picnic tables, and more.

spotted lanternfly on wood pallets

Spotted lanternfly egg masses hitch rides on vehicles and stacks of wood, like this wood pallet

Eggs hatch in the spring and early summer (late April / early May), and nymphs begin feeding on a wide range of host plants (see the list below). You’ll find active nymphs throughout the summer and early fall.

Adults appear in late July and tend to focus their feeding on tree of heaven (Ailanthus altissima) and grapevine (Vitus vinifera), although you’ll find them on a wide range of plants.

How does SLF spread?

While the Spotted Lanternfly can crawl, hop and even fly short distances, it mostly spreads by hitching a ride.

The adult SLF lays eggs on almost any surface, including vehicles, trailers, outdoor equipment, firewood, and patio furniture, and can be spread long distances when people move infested material.

spotted lanternfly egg mass on blue metal object, possibly a dumpster

SLF egg masses can be on almost any object, so be sure to check for them before transporting anything

Never move firewood from areas with active SLF populations, and carefully check for egg masses on all surfaces (including the underside!) of any objects that have been outdoors.

Which trees does the Spotted Lanternfly attack in CT?

Plenty! The destructive SLF has a taste for a wide range of Connecticut trees.

Although the SLF’s preferred tree is the weedy, invasive Tree of Heaven (Ailanthus altissima), the insect also attacks valuable tree species, including fruit and nut trees and almost 50% of Connecticut’s forest trees.

Forest tree species attacked by SLF include:

  • Red maple (Acer rubrum)
  • Sweet birch (Betula lenta)
  • Sugar maple (Acer saccharum)
  • American beech (Fagus grandifolia)
  • Eastern hemlock (Tsuga canadensis)
  • Eastern white pine (Pinus strobus)
  • Northern red oak (Quercus rubra)
  • American hornbeam (Carpinus betulus)
  • Yellow Birch (Betula alleghaniensis or B. lutea)
  • White oak (Quercus alba)
spotted lanterflies on plant stems

Spotted lanternflies can cause damage to many woody plants and trees

The Spotted Lanternfly also feeds on other tree species, including:

  • Paper birch (Betula papyrifera)
  • Black gum (Nyssa sylvatica)
  • Dogwood (Cornus)
  • Elm (Ulmus)
  • Linden (Tilia)
  • Pignut and shagbark hickory (Carya species)
  • Poplar (Populus)
  • Sassafras
  • Serviceberry (Amelanchier)
  • Sycamore (Platanus)
  • Tulip poplar (Liriodendron)
  • White ash (Fraxinus americana)
  • Willow (Salix)
a spotted lanternfly with its wings open on a tree trunk

It may look pretty, but the Spotted Lanternfly is a destructive nuisance that could decimate Connecticut’s agricultural sector and kill our trees

Vulnerable fruit and nut species include:

  • Almond
  • Apple
  • Apricot
  • Cherry
  • Nectarine
  • Peach
  • Plum
  • Walnut

Other valuable non-tree, commercial crops whose fruits can be ruined by SLF include:

  • Grapes
  • Hops

Where has the Spotted Lanternfly Been Found in Connecticut?

In Connecticut, one insect sighting was reported late in 2019 (a dead adult was also found near Farmington in 2018). This suggests that SLF is expanding its documented range but has not yet established itself in our state.

It is also the best reason for all of us to look out for SLF and to report any sightings! The earlier this destructive pest can be controlled, the less of a chance it has to reproduce, spread, and damage valuable forest, crop, and landscape trees.

What should I do if I find SLF in Connecticut?

Close up of a shoe, about to stomp on several spotted lanternflies

Stomping on Spotted Lanternflies is encouraged!

  • If you think you have found a Spotted Lanternfly, document it with your camera and submit your photo and location (very important) to ReportSLF@ct.gov.
  • Then capture and discard it in a plastic bag, or just stomp on it. Since there are no natural predators to kill this insect it’s up to us to control it. Killing any that we find is the best method to prevent SLF from reproducing. Stomping on beneficial or harmless insects is frowned on but stomping on SLF is encouraged!

The USDA’s Animal and Plant Health Inspection Service (APHIS) also provides the following resources to help you identify and fight SLF in Connecticut.

If I have Tree of Heaven in my yard, should I remove it?

Removing any Ailanthus altissima from your garden or neighborhood is an important control measure. Because this is SLF’s preferred tree, reducing the number and location of Tree of Heaven specimens helps to slow and concentrate SLF spread. In Pennsylvania and New Jersey, the Tree of Heaven is used as a “trap tree” by injecting it with a pesticide that kills SLF as it feeds.

A tree of heaven tree

Tree of Heaven is the spotted lanternfly’s favorite snack

If you’re not sure whether you have Tree of Heaven on your property, check this visual identification guide.

What’s Being Done in Connecticut to stop SLF?

In states with Spotted Lanternfly infestations, chemical and biological controls are being tested and used to control this invasive pest.

Currently, pesticide injections and sprays that kill SLF can be applied only by a CT Licensed Arborist. Spraying any tree for SLF should be done by a professional, as the canopies of large trees can only be reached and effectively sprayed using professional-scale equipment.

Other control measures include destroying egg masses and using sticky wraps around tree trunks to prevent nymph-stage insects from crawling up into tree canopies.

You Can Help Us

All Connecticut residents are asked to keep an eye out for this highly destructive insect. Citizen reporting is an extremely valuable resource for combating the potential destruction of our trees.

…And We Can Help You

As Tree of Heaven is the most common host tree for SLF, these trees need to be examined and treated before being removed. Since the Tree of Heaven can grow to 100’, treating and then removing them should be left to professionals. Our staff is experienced and trained in proper tree removal and can safely (and quickly) remove these trees, while also checking other tree species for any evidence of SLF.

If you’re concerned about Spotted Lanternfly and would like us to examine or remove any of your trees, just give us a call at 203-418-7491 to set up an Arborist consultation.

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