Should you still squash spotted lanternflies? Here’s what to know

Scientists and lawmakers alike are looking for ways to combat these invasive insects. But do they still present the same environmental harm as we originally thought?

Late summer is that notorious time of year when spotted lanternflies transform from inconspicuous, polka-dotted nymphs to big, bumblebee-sized insects clinging to tree trunks and fluttering through the air.

These non-native insects in the planthopper family were accidentally introduced to the U.S. in 2014—possibly on an international shipment bound for Berks County in eastern Pennsylvania.

While harmless to humans—and actually rather beautiful to behold, thanks to their crimson and yellow markings—the bugs feed on over 70 different kinds of plants and trees in the U.S. alone, making them an invasive species. They have a taste for certain plants, namely tree of heaven—also an invasive species from Asia—as well as native species, such as black walnut, several species of maple, hops, and grapevines.

The threat posed to American agriculture is why a bipartisan group of lawmakers recently introduced a bill called the Spotted Lanternfly Research and Development Act, which would make competitive grants available for research projects related to the mitigation of the invasive species.

“Across our community, I hear time and again about how devastating these pests can be,” says Pennsylvania Representative Chrissy Houlahan in a press release. “Whether you’re a farmer, a homeowner, or just someone who enjoys the delicious produce grown by our community’s farmers, the invasive Spotted Lanternfly poses a serious problem.”

Here’s what to know about the invasive species, and what’s being done to minimize their harm.

(Inside the race to kill an invasive menace—before it gets to a town near you.)

Why spotted lanternflies are so bad for plants

While lanternflies don’t appear to kill most trees outright, as was initially feared, large aggregations can affect plant health.

As true bugs in the order Hemiptera, spotted lanternflies suck nutrients out of host plants with mouthparts that act like a hypodermic needle.

“It’s really different from what most insects do, which is chew on plants,” says Holly Shugart, an entomologist and postdoctoral researcher at Pennsylvania State University. 

Worst of all, the spotted lanternfly is a skilled hitchhiker, able to cling to surfaces that travel at high speeds, such as cars and trains. Their putty-like egg masses, each of which contain between 30 to 50 eggs, can survive months of extreme weather and cold on a variety of surfaces, such as tree bark or the side of a shipping container.

Where are spotted lanternflies wreaking the most havoc?

Since arriving in the U.S., spotted lanternflies have exploded in number and can now be found from Massachusetts and Virginia to Illinois and Tennessee. Unfortunately, the insects arrived in a new location last year—one long feared by those in the wine industry.

“We’ve always told the growers in the Finger Lakes, it’s not a matter of if they get here. It’s when they’ll get here,” says Hans Walter-Peterson, a viticulture specialist for Cornell University’s Cooperative Extension.

(Invasive spotted lanternflies have a taste for grapes—what does that mean for wine?)

When too many lanternflies siphon nutrients from a grapevine, they can reduce fruit yields, affect fruit quality, and even kill the host plant. They can also transmit nasty pathogens to those plants, such as black sooty mold.

Because of these factors, researchers in one study estimated that in Pennsylvania alone, spotted lanternflies could lead to an economic loss of $554 million annually and almost 5,000 jobs. 

Can we eradicate spotted lanternflies completely?

While people in parts of the Northeast and Midwest are already well aware of the insects, and some have even been smashing them on sight—as many local governments and scientists have suggested—vigilante bug hunters won’t be enough to curb the spread, experts say.

Fortunately, however, there’s evidence that native predators are starting to get a taste for the foreign insect. In lab tests, spined soldier bugs and Carolina mantises have proven to be effective lanternfly predators, and blue jays, cardinals, chickens, spiders, yellowjackets, and ants have all been observed eating lanternflies out in the wild.

Lanternfly-sniffing dogs are also emerging as a promising new avenue in the effort to prevent these spotted insects from popping up in new places. Just as canines have been trained to sniff out explosives, drugs, and even viruses like COVID-19, the animals may also be a critical tool in the fight against invasive species.

(Learn how dogs put their noses to work sniffing out wildlife.)

“Pretty much everything has a smell,” says Sally Dickinson, a doctoral candidate at Virginia Tech.

And that goes for spotted lanternfly egg masses, which the insects produce in the fall and secrete in out-of-the-way hiding spots. In nature, that might mean the underside of a branch, but in human-dominated environments, that includes metal or plastic, like a railroad car, just as well as wood.

Other researchers are working on new pesticide formulations and application methods, but so far, no one has landed on a silver bullet solution to the lanternfly problem. That’s why funding new science on eradication is so critical.

“This invasive pest inflicts severe damage, threatening not only our crops but the livelihoods of hardworking farmers and the very future of our agricultural communities,” says New York Congressman Langworthy in the press release. “This crisis can no longer be ignored.”