(2/1) Lycorma delicatula, commonly known as the Spotted Lanternfly (SLF), is a new invasive insect that has spread throughout southeastern Pennsylvania since its discovery in Berks County in 2014. Although the insect has not yet been found in this part of the state, it’s very close - Lancaster County is the closest quarantined county - and it is just a matter of time before they are seen in south central PA and northern MD. The quarantine regulates or limits the movement of plants, plant-based materials and outdoor household items out of the quarantine area unless certain conditions are met. SLF presents a significant threat to Pennsylvania agriculture, including the grape, tree-fruit, hardwood and nursery industries, which collectively are worth nearly $18 billion to the state's economy. Homeowners also could sustain damage to high-value ornamentals in their landscape.

Native to China, India, Japan and Vietnam, the spotted lanternfly does not attack fruit or foliage. Rather, it uses its piercing-sucking mouthparts to feed on the woody parts of plants — such as tree trunks or branches and grape vines — where it excretes a substance known as honeydew and inflicts wounds that weep with sap. The honeydew and sap can attract other insects and provide a medium for growth of fungi, such as sooty mold, which covers leaf surfaces and can stunt growth. Plants with heavy infestations may not survive.

SLF eggs hatch in May. There are four instars (immature stages) of this insect. In the first three instars the insect nymphs are black with white spots. In the fourth instar, the nymphs are red and black with white spots, and the adult has wings, with red underwings that only show when the insect is in flight. These adults appear in July and, although winged, they are not strong flyers, but great jumpers.

Are there any natural enemies of the spotted lanternfly?

Birds don't seem to like to eat them, and researchers have not found predatory or parasitic insects that are making a great impact on the population yet. Over time, natural enemies often do find invasive insect species, but for now this does not seem to be happening on a level that is making a difference.

Things to consider before you purchase an insecticide

In some infested properties there are thousands of spotted lanternflies and many of them are very high up in trees. It will be difficult to reach the insects with a small can of spray or even a backpack sprayer. In this case you might consider hiring a professional tree care service to do the application.

Also, when the canopy of a tree is sprayed, the insecticide can come into contact with beneficial insects including pollinators and other creatures. People are looking for more specific approaches to pest management to minimize off-target exposure. This type of strategy is known as Integrated Pest Management (IPM). The PDA has been using an IPM strategy for spotted lanternfly infestations, and landowners may consider using the same IPM strategy on their properties, or hiring a professional service to do it.

IPM strategy for the Spotted Lanternfly

Locate Ailanthus altissima (Tree of Heaven) trees on the site. For reasons not understood, spotted lanternfly seem to prefer some individual tree-of-heavens to others. Try to identify the specific trees that are most attractive to the insects, based on how many are feeding on them.

Destroy approximately 90% of these trees, leaving only a few that are most attractive to the insect. They will serve as "trap" trees. It is recommended that you try to kill all the female tree-of-heavens, because they produce seed and contribute to the spread of this invasive tree. Be careful handling tree-of-heaven wood, leaves and branches. Chemicals in the sap of this tree can cause headaches, nausea and possible heart problems. Wear gloves and protect yourself from exposure.

When you cut down tree-of-heavens, they will sprout profusely from the stumps and can grow back in a few years. Because they regenerate so easily, it is recommended that you treat the stumps with an herbicide to kill them and prevent them from sprouting new shoots.

Herbicides that are labelled for this use usually contain one of the following active ingredients triclopyr, dicamba, imazpyr or glyphoshate. Use the herbicide carefully and according to directions on the label. Alternative methods for using herbicides to kill tree-of-heaven include foliar sprays, basal bark applications and a method called frill application or "hack and squirt." The Penn State Extension publication, Herbicides and Forest Vegetation Management, has more information about these methods. Whichever method you choose, remember that you will have dead trees, which may eventually have to be removed.

Treat the remaining tree-of-heavens with a systemic insecticide that will move throughout the tree. The insecticide must be applied according to the label and at the right time of year for the trees to absorb it. When spotted lanternflies feed on correctly treated trees, they will die. Systemic insecticides that are labelled to treat ornamental trees usually contain the active ingredients dinotefuran or imidacloprid. The PDA is using dinotefuran in their IPM strategy.

Treating only a few trap trees with a systemic product can reduce the amount of insecticide released into the environment and may help conserve beneficial insects.

Avoid spreading the spotted lanternfly

It is important for landowners in the affected area to avoid spreading the spotted lanternfly. Avoid parking or storing things under trees in infested areas.

The female SLF often lays eggs on objects that are under the trees she is feeding on. You should try to change your habits about where you park. Park vehicles in open fields, away from tree lines, or in a closed garage if possible. You should not store things that you might need to move to outside of the quarantined area under infested trees. These things include firewood, tools, construction supplies, equipment, or any other solid object.

If you visit a quarantined area, inspect all items that will be leaving with you from the quarantined area.

You should remove and destroy any SLF that you find before you move the item. Also check all vehicles, trailers, campers and equipment including around windshield wipers, grills, wheel wells, and truck beds. Inspect plant material, woody debris, lawn furniture, construction supplies, tools, and all solid objects. Remove SLF manually or use a pressure washer. You can destroy mobile stages of SLF mechanically by crushing them. Destroy eggs by smashing them or scraping them into a container of rubbing alcohol.

If you find a spotted lanternfly in a municipality where it is not known to exist

You should try to capture it and put it into a vial filled with alcohol to kill and preserve it, or at least take a good picture of it. Report it to the Pennsylvania Department of Agriculture (PDA) by emailing to: badbug@pa.gov or call the Invasive Species Hotline at 1-866-253-7189. Your discovery could add additional municipalities to the quarantined area.

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