Over the past several weeks, Master Gardeners in the Beaver County program have received lots of questions about Spotted Lanternfly (SLF), Lycorma delicatula.
Chief of all questions, of course, is “what can be done?”
Folks most often want to know what they can do or spray to keep these pesky bugs out of their landscape. Despite the vast amount of information you might find on the internet, much of it ends up being less than helpful. I hope to address a few common questions we get and waylay some fears around the impact these nuisance pests can have.
Generally speaking, it's very unlikely that spotted lanternflies will outright kill a tree or larger landscape plant in your yard.
They can cause some stress to trees such as maples, walnuts, etc., but their preferred tree is their native host plant back in eastern Asia – the Tree of Heaven (Ailanthus altissima), which is an invasive tree here in western Pennsylvania. It’s easy to become alarmed when you see a swarm of SLF crawling up a tree in your yard, but they typically will not be so impactful as to cause lasting or lethal damage to your tree.
The first approach to dealing with spotted lanternflies is physical control. These methods include stomping or smashing SLF whenever possible, trapping them using circle tree traps, or even vacuuming them with a shop vac.
When stomping, approaching them from the front can often be more effective because of the way their eyes are situated on their heads, and that if they jump away, following them for a couple more jumps can often lead to a successful kill because they lose strength and cannot hop indefinitely.
For trapping, see the Penn State Extension website on Spotted Lanternflies for step-by-step instructions to make and install a circle trap around your trees: https://extension.psu.edu/how-to-build-a-spotted-lanternfly-circle-trap.
These traps work with the SLF’s biological tendency to climb up tree trunks and their inability to back down. Sticky traps may be effective, but always use a wildlife barrier made of mesh or screening to prevent birds, butterflies, bees, and other beneficial insects from accidentally flying into the trap and getting stuck.
Vacuuming SLF can be a very effective mechanism for controlling medium to large swarms. Using a shop vac with water in the basin and sucking up as many as possible will cause the SLF to drown – no insecticides are needed in the base.
If you would like help determining whether chemical intervention is warranted in your situation, you are welcome to call or email our Master Gardener hotline at 724-371-2062 or firstname.lastname@example.org. They will ask some questions about your situation and help you weight the pros and cons of different approaches from a scientific point of view.
We also have several resources available on our website to help homeowners decide if they should spray: https://extension.psu.edu/deciding-if-and-when-to-treat-for-spotted-lanternfly-on-ornamentals.
Social media abounds with home remedies for dealing with SLF. One common solution posed is to mix dish soap with vinegar in a spray bottle and squirt the solution onto SLF. Another one I see is to mix Pine Sol with sugar and water and leave it in an open dish on your patio or porch; supposedly SLF will be attracted to the smell and will stumble in and drown.
It’s easy to see the appeal of solutions like this; they’re inexpensive and use products that you probably already have at home, and many believe that since they are commonly used in the home, they must be safe to use in the yard and may even be safer than “toxic pesticides.” However, this is not true. Scientists and researchers (and Master Gardeners!) know that just because a product is safe for use in the home does NOT mean that it is safe to use in the garden.
Pesticides are highly regulated by the EPA and other organizations, and there are strict rules around usage, including how much to use, when to apply it, and the time needed in between applications. Because household products like dish soap, vinegar, and Pine Sol are not regulated by these governing bodies, we have no information about what concentrations, doses, or application rates might be safe or effective. Some of these products, like vinegar, for example, are also very toxic for pollinators like bees and butterflies, and some can cause lasting damage to or even kill your plants.
We recommend only using products that are registered with the EPA as pesticides to fight SLF – all registered insecticides have a registration number listed on the label. If you are concerned about using toxic chemicals in your yard or prefer to garden organically, there are several organic options available that are still effective against SLF but pose a smaller risk to beneficial insects or other wildlife, such as neem oil and horticultural (or insecticidal) soaps.
For organic options, look for the “OMRI” designation on the label – this stamp of approval from the Organic Materials Review Institute means that the product is safe for organic use, but it still has all the information needed about concentration, dosage, application rates, etc. so you can trust that you’re using it in a safe and effective way.
You may have heard success stories of neighbors and friends employing home remedies to address SLF, but just remember that you might not have the whole story if plants or beneficial insects were harmed in the process, and that a few success stories are not a replacement for thorough regulation and official recommendations.
Penn State Extension has much more information about SLF that may be helpful to you; check out our website for help identifying, reporting, and managing SLF: https://extension.psu.edu/spotted-lanternfly.
Remember that soon, SLF will start laying egg masses, and one of the best control methods will be to scrape them off tree trunks, sides of buildings, and outdoor equipment and destroy them – see our website for more information on egg masses.
I’ll leave you with a bit of hope: researchers believe that we will not be overwhelmed with SLF forever.
Eventually, populations will even out as wildlife learn to eat them and as human-implemented control methods are consistently employed. We are already seeing decreases in SLF populations in the eastern part of the state, where they were completely dominating a few years ago.
Here in Beaver County, we may see it get a little bit worse before it gets better, but most likely, nature will eventually take its course and we won’t be plagued forever.
Lyndsay Feather is a horticulture educator and coordinator of the Penn State Master Gardener program in Beaver County
This article originally appeared on Beaver County Times: Over the Garden Gate: Spotted Lanternflies: Solutions, home remedies and a bit of hope