By: Amy Hopf, Digital Content Associate

An “invasive” insect is a bug that is not native to the United States. Usually, these species spread quickly and are harmful to local plants and wildlife.

The spotted lanternfly (SLF) is an invasive insect. It is known for destroying fruit trees, maples, and other members of our urban forest.

The USDA has confirmed populations of spotted lanternfly in four locations:

  • The Horticulture Center in West Fairmount Park
  • The north end of Wissahickon Valley Park
  • The south end of Wissahickon Valley Park
  • Along Valley Green Road in Wissahickon Valley Park

What does a spotted lanternfly look like?


Photo credit: Pennsylvania Department of Agriculture

The image on the top left shows an adult that is displaying its red hind wings. You can see the bug’s red hind wings when it is startled, or when it flies. Most of the time, the adults sit with their wings folded over their backs (as shown in the image on the right, above).

What does the spotted lanternfly do?

The spotted lanternfly is a plant-hopper with piercing-sucking mouthparts. It inserts these mouthparts like a straw to feed on the sap flowing through the trunk, stems, and leaves of host plants.

This process leaves damage to the tree. Trees with high numbers of SLF feeding on them become stressed and more vulnerable to attack by other insects and diseases. A number of tree species have died due to the spotted lanternfly.

SLF feeds on a wide range of plants, including:

  • Ailanthus (Tree of heaven): preferred host species
  • Grape
  • Apple
  • Maple
  • Birch
  • sycamore
  • Willow
  • Staghorn sumac

Females lay eggs in rows, starting in October, with 30-50 eggs per egg mass. One female may lay 2 egg masses before the end of the season.

What is being done about this?

The bugs cause damage to many trees and plants in our area. Because of this, there are Integrated Pest Management (IPM) strategies in place to target these pests. IPM uses environmentally sensitive practices to target a pest with the least toxic but most effective practices.

IPM practices for SLF include:

  • Avoid moving them around
  • Scrape eggs and sticky bands mechanically
  • Remove/reduce Ailanthus altissima trees
  • Use pesticides carefully
  • Encourage beneficial insects

There is a quarantine order to try to contain the invasive bug. The order states that no one may willfully move any viable life stages of the SLF from within the quarantined area to outside. Residents should inspect any items for SLF or egg masses before moving those items to outside the quarantined area.

What can I do to help?

If you see a spotted lanternfly or its eggs, there are a few things to do to help:

There are various ways to destroy the SLF or its eggs, including scraping into a container of rubbing alcohol, smashing the eggs, or using insecticides. Please make sure the insecticide is labelled as appropriate for the site you intend to use it on.

Volunteers have reported destroying about 1.5 million SLF through egg mass scraping. It is important to know that SLF does not bite people.

Read more information on the spotted lanternfly, how to properly destroy the insects, and what else you can do to help.