As summer begins, Lebanon is starting to have sightings of spotted lanternfly nymphs across the county.
LebTown spoke with Casey Clauser, Lebanon Master Gardener Coordinator of PennState Extension, and Olivia Bingeman of the Lebanon County Conservation District to find out more about these pests, and how to deal with them.
To jump to a specific section, follow the links below.
- What are spotted lanternflies?
- What problems do they cause?
- What can be done to control the population?
- What resources are available to help deal with spotted lanternflies?
What are spotted lanternflies?
Spotted lanternflies (SLF) are an invasive planthopper species, first noticed in Pennsylvania in 2014. Since then, a total of 26 Pennsylvania counties have confirmed spotted lanternfly sightings.
The pests hatch in spring and reach adulthood in July, remaining active until winter.
Spotted lanternfly nymphs, upon hatching, are small (around an eighth of an inch in length) and black in color. During this time, they may reside on certain trees or on small plants and flowers, such as roses and grape vines.
Later in their adolescence, nymphs take on a red-black pattern and reach around a half inch in length.
In their adulthood, spotted lanternflies grow to over an inch in size, with black spots on their wings and distinct red coloring. Adult spotted lanternflies typically reside and feed on trees, such as Willow, Sumac, River Birch, Silver or Red Maple, and the invasive Tree-of-heaven.
What problems do they cause?
First and foremost, spotted lanternflies generally do not kill trees. However, after feeding on various types of plant matter, they secrete honeydew, a substance capable of interrupting photosynthesis of plants if it covers them.
“If you have plants under trees that that honeydew is falling on, it could create what’s called ‘sooty mold,’ which would reduce photosynthesis so then the plants might not do as well,” explained Clauser. “In trees, we don’t see a huge issue with the life of the tree, but quality of life around that tree could be an issue.”
Honeydew is known to reduce the yields of produce-bearing plants, particularly grape vines (on which spotted lanternflies can live their entire lives) and fruit trees. This is particularly the case when large amounts of the pest take residence on a plant.
“If [spotted lanternflies are] on grape vines or fruit trees, any stress on those plants will limit any sort of production,” said Bingeman. “That’s an important issue.”
There have also been some reports of pets having negative reactions to consuming spotted lanternflies. While no toxins have been found in the insects, according to Penn State Extension, this is not conclusive.
“It appears that more studies would need to be done to completely rule out the possibility [of SLF being poisonous to animals],” said Bingeman. “If your pet becomes ill, contact your veterinarian right away.”
What can be done to control the population?
As an invasive species, there are not many natural checks on the population of spotted lanternflies. However, there are a variety of methods humans can use to curb the population.
Trapping
One can equip a tree with a sticky trap or the more recently popularized circle trap to collect and kill large amounts of the pests. This is particularly effective during the nymph stage, as spotted lanternfly nymphs are less able to escape traps and more likely to climb the trunk of the tree, where traps are located.
“We are at the best time to control spotted lanternfly,” said Bingeman. “Because at this point, they’re small and they’re relatively easy to catch. What happens is, they fall off the tree because they’re weak, and then they have to climb back up, and that’s when the sticky tape is really useful.”
A sticky trap is essentially a large piece of sticky tape, wrapped around the trunk of a tree. These are effective at capturing and killing spotted lanternflies, but also pose a risk to other bugs, birds, and even mammals like squirrels. One can wrap mesh around the trap to avoid most bycatch.
“The sticky traps, if people do want to use them, we really highly recommend that they use some type of protective covering,” explained Clauser. “In the past a lot of people used chicken wire, and really that’s not enough. It should be an insect screening you would use for your window, that way it really reduces the amount of opportunity for beneficial insects, for birds, other things that may get stuck to those sticky bands.”
The circle trap is a recent innovation that avoids the bycatch issue of sticky traps, though it is also more complicated to use and more expensive to purchase. However, it can also be made from scratch, as this PennState Extension guide describes.
“The really big benefit of the circle trap is it’s not gonna get bycatch; it’s not gonna get squirrels, it’s not gonna get birds,” said Bingeman. “It’s a little more difficult to use though. It takes a few videos to figure out how to put it up.”
Clauser recommends circle traps over sticky traps, both because of reduced bycatch and increased effectiveness for adult spotted lanternflies.
Both types of traps work best on trees with smooth bark. Those who set up the traps are advised to check them semi-frequently to remove trapped insects. Sticky tape typically lasts a few weeks, whereas circle traps last the whole season but need emptied occasionally.
Pesticides
When large amounts of spotted lanternflies are in one location, pesticides can be used to reduce their populations. However, pesticides should not be used for small amounts of the pest, or when their use also puts beneficial insects at risk, such as on flowering plants that bees are likely to visit.
“Insecticides are always good to use as long as you read the label and understand what they’re meant for,” said Bingeman. “Make sure we’re never applying on flowering plants, because that’s something bees are attracted to and we kill bees that way.”
Different pesticides have different effects on the environment and spotted lanternflies. Bingeman recommends pesticides with active ingredient Carbaryl, Bifenthrin, or Beta cyfluthrin for spotted lanternflies.
While spraying plants does typically kill the nymphs currently on that plant, it may not prevent more from covering the plant in the future.
Clauser noted that while a variety of home remedies have been used to spray spotted lanternflies, these methods have generally not been studied extensively for environmental impact or effectiveness on pests.
“Penn State Extension’s stance for any home remedy is essentially that any of those methods are not tested to be used as an insecticide to kill insects,” he said. “So although it may kill insects, we always recommend that people use an EPA labeled insecticide because they’ve been studied to be used as an insecticide.
“Technically, if you’re spraying something as an insecticide that’s not designed as that or not following the label correctly of an insecticide, it’s technically illegal to spray something that’s not designed,” Clauser continued. “We always say, if you’re going to use them, follow the instructions.”
Another method of chemical control is systemic insecticides. Essentially, this method puts insecticide into a tree’s sap so that bugs that consume it—such as spotted lanternflies—consume the insecticide and die as a result. Generally, this method is used later in the spotted lanternfly season (as nymphs often cannot get through their bark to feed) and is administered by a professional to a particularly infested tree.
“Probably the best way to control them when they’re adults is through systemic insecticides,” explained Bingeman. “You have to call a professional out to spray a tree that will suck up that pesticide, and then when the spotted lanternfly feed on it it’ll kill them. That’s something that most tree care companies can do.”
Other methods
Sometimes, particularly during the nymph stages, spotted lanternflies will take up residence on blooming flowers or other plants that rule out the options of pesticides and tree trapping. In these cases, there are a few remaining options.
One is to manually pick the nymphs off of affected plants. Nicole Welch, a Lancaster resident, has been brushing nymphs off her plants and into jars of water so that they cannot survive to adulthood. She does this twice a week or more.
“At my house they don’t climb our trees, instead they prefer the roses and other plants that have longer stems, things we can’t use the tree tape on,” Welch explained in an email to LebTown. “We also have a lot of edible plants in our garden, so we don’t use many pesticides. I take a mason jar half full of plain water and use my hand to ‘herd’ them into the jar.
“They drown within 48 hours, and can be dumped anywhere since it is just water and dead bugs. It takes time to do this, but I find it easier than trying to follow where they jump to squish them.”
For an easy deterrent, Clauser recommends using a hose to spray nymphs off of plants. While it will not kill the nymphs, it will drain their energy and could discourage them from returning.
“Knocking them off, they may crawl back up, but they’re going to be taking energy going back and forth, and that may limit them on trying to come back to the plant,” said Clauser. “That’s something you can easily do as you’re watering your plants.”
Individuals are also advised to keep an eye out for Tree-of-heaven plants. The invasive species serves as a perfect home and food for spotted lanternflies, in addition to being generally detrimental to the local ecosystem.
“The spotted lanternflies prefer these trees and breed better, and live better, and grow better when they have access to these trees,” said Bingeman.
Due to that, the trees should be cut down and killed using herbicides. If herbicides are not used, the roots will stay alive and create more trees down the line.
“We encourage people to remove it from their property regardless of the spotted lanternfly,” urged Clauser.
What resources are available to help deal with spotted lanternflies?
Spotted lanternfly sightings can be reported at PennState Extension, which keeps track of where across the state the pest has been spotted.
While last year the Lebanon Valley Conservation District received state funds for control projects, it and other conservation districts across the state do not have that funding this year. However, the Pennsylvania Department of Agriculture is still undergoing control projects.
“We don’t know what reasoning was behind this, but no conservation districts got funding to do their own projects,” said Bingeman. “The Department of Ag is still doing projects, but the individual counties are not.”
Bingeman advised that individuals concerned about spotted lanternflies on publicly owned property, such as parks, first contact their municipality to see if circle or sticky traps could be put out, then report the infestation to the Department of Agriculture.
For more information on the species and how to handle it, visit PennState Extension’s Spotted Lanternfly Guide, which was heavily consulted in the development of this article.
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