In 2014, the spotted lanternfly made its first appearance in Pennsylvania in Berks County, located in the southeast region of the state. Now the invasive pest can be found in 45 of Pennsylvania’s 67 counties, including Allegheny, Beaver, Washington and Westmoreland counties.
Unfortunately, with that small insect comes big trouble—Penn State economists estimate that if not contained, the spotted lanternfly could potentially drain Pennsylvania’s economy of at least $324 million annually.
Originally from Southeast Asia, the insect has spread across the state as well as through New Jersey, New York, Ohio, Connecticut, Maryland, Delaware, Virginia, and West Virginia by hitching rides on ground transportation.
“The spotted lanternfly is a really avid hitchhiker,” said Chris VandenBosche, Penn State Extension educator and Master Gardener volunteer coordinator of the pest that is thought to have entered the U.S. on a shipment of landscaping rock. “They are very poor fliers, so they don’t fly long distances. The bugs lay their egg masses on trains, trucks, RVs or other vehicles traveling between counties, and those eggs hatch when they’ve matured.”
Checking for egg masses on your vehicle, camping equipment or any other items stored outdoors can help prevent you from accidentally bringing them to your favorite places or back to your own yard.
According to VandenBosche, the spotted lanternflies’ biggest impact on the state is as an agricultural pest that impacts fruit production—most critically grapevines, but also fruit trees. The pest feeds on sap from over 70 different plant species, including other economically important plants such as maple trees, black walnut, birch, and willow. The feeding damage significantly stresses the plants, which can lead to decreased health and potentially death.
“They don’t normally kill plants like trees and shrubs, except for brand new saplings,” said VandenBosche. “They do take out Tree of Heaven, another invasive species, which comes from the same region in Southeast Asia. It’s a familiar meal to them.”
As the insects feed, they excrete a sugary substance known as honeydew, which attracts bees, wasps, and other insects. The honeydew also promotes the growth of fungi.
“This dark, grayish black, sooty mold occurs pretty much anywhere the waste falls,” said VandenBosche. “If it grows on pachysandra, for example, the plant can struggle to photosynthesize, because it obscures the surface of the leaves from getting sunlight.”
While most homeowners and gardeners find the spotted lanternfly to simply be a nuisance—it does not bite, is not venomous, and has not shown to be poisonous to household pets—it’s still important to try to get rid of the insects before they cause too much damage.
Spotting the Spotted Lanternfly
While it can be difficult to spot a spotted lanternfly in the nymph stage when they are no bigger than a pencil eraser, it’s pretty easy to identify them as adults.
“Because they are very poor fliers, they mostly jump—and they’re very clumsy,” said VandenBosche. “A lot of times that means they’re bumping into you.”
The adult spotted lanternfly is about an inch long and has grey wings with black spots. When it opens its wings, it reveals a bright red underwing. And there’s a good chance that if you see one….there will be more.
“They are even in downtown Pittsburgh, with an especially heavy population around the rivers,” said VandenBosche.
Depending on the size of an infestation, the Penn State Extension office is happy to provide advice on whether to wait out the pest to see if the population decreases or to use eradication measures. VandenBosche said that homeowners who find egg masses should scrape them off of trees and submerge them in rubbing alcohol or hand sanitizer—if they are just thrown in the garbage, they will still hatch.
She added that while there are direct contact pesticides approved for eradicating the spotted lanternfly, it needs to be sprayed directly on the insect, which is quite labor intensive—especially if they’re located on the top of a 40-foot oak. Systemic pesticides, which are absorbed by a tree and enter the insect during their feeding, are available, but small quantities such as a homeowner needs may be difficult to purchase.
“If you have a high value tree, you can speak to an arborist about possible approaches,” said VandenBosche, adding that the Penn State Extension office does offer demos on how to build a spotted lanternfly trap that can funnel the pests into a bottle or bag as they climb trees for easier disposal.
“It’s really important to not use sticky traps at all costs,” she added, noting that this was originally recommended as a disposal method. “We’ve found far too much bycatch in these traps, including critical populations of endangered insects, small birds and bats.”
The extension office also asks that people report spotted lanternfly sightings to Penn State when they are first spotted in an area, especially in a county where they have not been seen before. Reach Penn State by calling 1-888-4BAD-FLY or 1-888-422-3359 or visit the website at www.extension.psu.edu/SLF.
If you have questions or concerns about the spotted lanternfly or other garden issues, you can talk to a master gardener by calling the hotline staffed by volunteers at 412-482-3476, or you can email firstname.lastname@example.org.
On July 29, the master gardeners will also be holding Garden in the Park, a free event for the public at North Park from 9 a.m. to 1 p.m. “We’ll have tons of master gardeners there who will be answering a wide variety of questions and will also be providing information on the spotted lanternfly,” said VandenBosche.