Spotted lanternflies worsened by higher temperatures. Here’s how to get rid of them 

Spotted lanternfly (SLF) nymphs have started their infestation earlier than usual this year. They are also growing up sooner. On July 12, the New York State Department of Agriculture and Markets (DAM) verified the first SLF within the five boroughs was in Long Island City, Queens. The first sighting of an adult in 2023 was in the same area nearly a week later — which might not sound like a big deal, but it is in SLF time. 

Experts say warmer temperatures earlier this year are responsible for accelerating their development. But growing up sooner does not mean the bugs will also die sooner — they will just have more time to wreak havoc on trees and make next year’s infestation worse. 

Confusion around how to kill them

Many New Yorkers don’t know how to kill spotted lanternflies. Nextdoor and other social media neighborhood groups have constant discussions on what to spray on trees to end infestations.

We asked two experts about the insect, how to get rid of it, and why we should care. The interviews are condensed and lightly edited for clarity. 

We first spoke with Brian C. Eshenaur, senior extension associate of Cornell University’s Integrated Pest Management Program.

Epicenter NYC: New Yorkers have been sharing home remedies ranging from spraying vinegar to Dawn dish soap. What have you found useful that does not kill a tree when you spray it?

Eshenaur: We really have to be concerned about some of those home remedies. And if you’re trying to kill a pest like the spotted lanternfly, it has to have an EPA label for us to do that legally. 

But for practical reasons, often those home remedies are not going to be effective. Something that is very basic, like vinegar, is going to be very acidic, which could harm the bark of the tree and even make its way into the tree. And it could alter the pH of the soil below. We want to avoid that, and some vinegars you can buy can be potentially harmful to us if you get it in your eye or other sensitive skin.

Soaps can be harmful to plant foliage if they are too concentrated or if they accumulate in the soil, the beneficial soil microbes and the roots could be harmed. 

We do have a list, on our Integrated Pest Management website, of products that are labeled and legal to use. But most people are not going to use them. 

Now, if you have a tree in your backyard — arborists can use a systemic product that they can inject into the tree, and then the whole tree is protected. And it’s only going to impact insects that are feeding on the tree, as opposed to just spraying it around. But those are limited to what tree-care professionals can use, so we wouldn’t have access to those as homeowners. 

But if you’re gonna kill them, you can use a vacuum to control them. Some people have seen them on some of their vegetable plants and have used a handheld, battery-powered vacuum and that works.

Epicenter NYC: What do you do with them after?

Eshenaur: Most of the time they don’t make it through the vacuuming process because when the vacuum brings everything through the impeller, it hits the fan and it kills him there. 

But some of them can survive. If you open up the canister, they could fly out. So you can leave them in for about 48 hours. If they don’t feed within about 48 hours, they will die. If you empty that canister a couple days after you’ve done it, then you’ll know that they’re all dead. 

If you have a lot of them in there, you wouldn’t want to wait beyond [48 hours] because the decaying spotted lantern fly, a large mass of it, can smell putrid. 

Epicenter NYC: Spotted lanternflies, as a non-native species, have few predators here. Given this, would you encourage New Yorkers to refrain from killing stink bugs, praying mantis, and other species known to kill spotted lanternflies?

Eshenaur: Absolutely. And if you are fortunate enough to have a garden, keep a little bit of a habitat area —  something that is not manicured to a high degree — for beneficial insects. 

Also, put in native plants that you know beneficial insects are more in tune to. Including some of those natives can be very helpful — things like butterfly milkweed.

Epicenter NYC: Why should people in neighborhoods with fewer trees care about SLFs?

Eshenaur: We know the benefit of having a tree landscaped in urban areas: a better sense of well-being, [protection from extreme heat]. We want to protect our trees as much as we can everywhere, so by stepping on spotted lanternflies as you’re going down the sidewalk, you’re doing your part.

We also spoke with Julie M. Urban, associate research professor in Pennsylvania State University’s Department of Entomology, about how SLFs escape and other ways to get rid of them. 

Epicenter NYC: What makes spotted lanternfly nymphs so fast and so hard to kill?

Urban: This species and their relatives are called planthoppers. Spotted lanternflies’ hind legs have these gear-like structures that allow them to pop. So they’re really specialized jumpers. Adults are larger, so there’s a bit of a trade off — they are able to fly and to glide, so that certainly helps them with any escape, but they’re larger, so their body mass will slow them down a little bit compared to nymphs. 

Epicenter NYC: What is the best trap to use? NYC Parks have expressed concerns about the safety of using traps on trees – for other wildlife and for the trees — especially given the costs of putting up traps. 

Urban: Birds have gotten stuck on sticky band traps. The circle traps’ risk is a little less problematic than the sticky ones. But there are modifications that a person could do to make the sticky traps safe. PennState still doesn’t recommend them, but if you were to look online, there’s the bug barrier trap. 

Epicenter NYC: If you want to try killing SLFs one bug at a time, what’s the best way to do that? 

Urban: Taking something like a Snapple bottle just a little bit above them and they jump up into it. Then, if you were to put [rubbing] alcohol [or hand sanitizer] in there to kill them, that would probably be the quickest and most humane way to do it. They’re never going to jump backwards, so everything is forwards. If it’s on the ground, it just might be easier to stomp them.